Ducati ST2 : Amateur Restoration Take 2

[Simon Davey]

This is all very methodical, and you seem to have incredible patience.

At least we all know where to bring our bikes when the need tuning.

[Hairsy]

Very kind of you to say so Simon but my patience just ran a bit thin!

 

I had a little moment of panic and thought that maybe the dab of loctite on the bleed screw might not have been such a good idea. Sure enough, the screw wouldn't move. My lack of patience led to me over doing it with a flathead screwdriver and I gouged out the end of the bleed screw.

 

Immediate reaction was to torch the bike. Next, slightly more measured reaction, was that I'd now set the bleed screw to the standard setting so maybe I shouldn't worry about it.

 

This was followed by my realisation that 'of course I'm going to worry about it because that's what I do'. So I spent half an hour with plus gas, some drill bits, some Torx bits and a hammer and I've now extracted the screw.

 

Given that I now need to source a new one, I thought it would be a good idea to pull the other one out so that I can take a picture / measurements / etc.

 

Then I noticed something odd - the good one has a little O ring on the end of it. It's at the end where you use the screwdriver, not the end that lets the air in. So the (now) dodgy one was actually defective anyway. In practice, given that it's on the 'other' end of the thread to where the bleed screw is doing its bleeding, I doubt this affects what it does. But perhaps that O ring is there to provide some friction and stop it coming loose. That would certainly explain how I got into this mess. Regardless of what it's for, it does appear to be evidence that someone has previously tampered in this area.

 

Anyway, I'm now on the search for a Throttle Body Air Bleed Screw for a 1998 Ducati ST2. It's not listed as a separate part by Ducati and my initial brief search online has come up with nothing. So guess what I'm googling this evening ...

 

And just in case seeing a picture prompts someone into saying "oh I know where that part is used on something else" ...

 

[Simon Davey]

I'd be inclined to pop that in a vise, and cut a slot in the top, and pop an o-ring on it. 

You haven't damaged the working part of the screw. 

Or, bodge it with PTFE tape at the top of the thread, that'll stop it winding itself in. 

Edited December 21, 2024 by Simon Davey

[Hairsy]

4 minutes ago, Simon Davey said:

I'd be inclined to pop that in a vise, and cut a slot in the top, and pop an o-ring on it. 

You haven't damaged the working part of the screw. 

Or, bodge it with PTFE tape at the top of the thread, that'll stop it winding itself in. 

That is most definitely plan B!

[Hairsy]

More progress but also more challenges. This project is well and truly testing me.

 

I decided that my desire for a perfect air bleed screw was silly and took Simon's advice. I've cut a slot in the mashed up screw and ordered some O rings - I have loads of sizes already but, of course, not the right one. Thank you Simon.

 

So I then moved on to the setup. I linked to the document I'm using a few posts ago so I won't bore you with the full process - just the high/lowlights.

 

First of all I made sure that I could open the ports in the manifold that I'll need to use for throttle body balancing. These felt super solid so I used a little more patience than yesterday and applied some Plusgas. 20 minutes later and I was able to loosen the plugs from both ports. Good news.

 

I then started the job of loosening off all the throttle stops / balance adjusters / TPS - these all need to be completely off to set the baseline for the TPS. These adjusters are a combination of Torx heads (nice), flathead screwdriver slots (acceptable) and 2.5mm Allen heads (nightmare). After 26 years, these could all be expected to be well and truly set into their threads - but Ducati decided to play safe and applied some very hard paint to all of the heads. I guess this helped to stop them coming loose - but it also helped to stop you getting a tool into the heads. A 2.5mm Allen key is already a rubbish tool for loosening something with 26 years of aging but when the head is full of paint it's even more stupid. I truly hate small Allen heads. Of course most of the screws were also in ridiculously difficult places to get to, including one of the Allen heads being completely impossible to actually see.

 

 

So I spent the best part of an hour painstakingly scratching the yellow paint away from the heads and applying lots of Plusgas. Every screw gave me stress as I tried to loosen it but the 2.5mm Allen heads were horrible.  However ... I'm delighted to report that I'm getting better at this and I did manage to get everything loose without destruction.

 

The guide I'm using for this job suggested that I'd need to unwind the balance screw between the two throttle bodies about 2 turns for it to release the link between the two cylinders. However it took over 4 turns to get to that stage. This does suggest a possible balancing issue but, like other suspicions I've head, there is evidence (the yellow paint) that the bike hasn't been tampered with in this area. So I'm not convinced it's a problem.

 

Before I loosened the TPS, I checked its output with everything loosened. The guide said I should expect this to be in the range 90 - 170 mV. It was 0. And reporting a negative throttle position.

 

 

I then loosened the TPS and tried to set it to the correct base setting of 150mV. Theoretically you simply rotate the sensor to read 150mV and then tighten it in that position. However, the lowest reading I could get out of it was 176mV and any further rotation gives me 0. This leads me to be suspicious of the TPS but, in practice, it will never be at the bottom of the range because once idle has been set the reading will be higher. The sensor does seem to provide a reasonable increase in voltage as the throttle's applied so I'm not throwing it in the bin yet - but it's on a final written warning. I did take it off the bike to try to clean it but it's a sealed unit. I sprayed contact cleaner everywhere that looked as though it might leak a bit inside but it didn't make any difference to this lack of low voltages.

 

I ended up setting it up at the point where the reading jumps from 0 to 150mV. I then set the throttle stop to give me the correct baseline voltage for the TPS (404 mV) and that seemed to occur where I'd expect it. So it might be OK.

 

I wound in the balance screw to roughly where it was before so that I could use this as a baseline for balancing the throttle bodies.

 

And then of course I hit my problem for the day - that lovely gold chassis that is part of the Ducati signature look is designed in a way that means I can't screw in the adapters for the balance ports - these are needed to connect the little hoses up to the borrowed Carbtune unit I'm using. The chassis is right in the way and the adapters are too long and interfere with the chassis so they can't screw in. If it were my own kit then I could easily just cut the adapters down but as it's borrowed I can't.

 

That's a problem I can't solve today so I thought I'd just try and start the bike and see if there's anything different. On initial start up it was making a weird putt putt noise which I quickly realised was the missing air bleed screw that's awaiting its O ring. I decided to refit it just for the test ... only I dropped it into an incredibly cunningly designed bit of engine that's almost impossible to retrieve air bleed screws from. 20 minutes later I did manage to get it out and finally was able to complete the test and ...

 

Exactly the same - runs OK but after dropping back to idle after revving it sometimes stalls.

 

I'm really not sure whether today has actually taken me any further forward but I guess, by definition, I'm one day nearer the end.

 

So I now need to source some shorter adapters for the Carbtune and then do the balancing and complete the setup.

 

If that's not successful (and I'm no longer pinning great hopes on anything being successful) then I think I'll probably need to get hold of a new TPS. I've had a quick check and the prices online range from £5.61 from AliExpress to £303.19 from Ducati. Heaven knows what I'll do - I've previously bought parts from AliExpress that have arrived in identical packaging to much more expensive UK sourced parts and been fine. But if I don't use an official part and it doesn't solve the problem then I'll never know. Maybe I just get a cheap one anyway and if it doesn't work then I've only wasted a few quid and I get a slightly more official one.

 

I suspect this might be it for work this side of Christmas - so if anyone is still reading then I wish you a Happy Christmas!

[Old-codger]

This is really testing your patience a lot of people would have thrown in the towel and stuck it in the shed and forgot about it or flogged off as a project. Thankfully ive never had to muck about with fuel injection on a bike just old fashioned carbs but I feel your pain. Have a break and come back fresh in the new year im sure you will get to the bottom of it. Happy xmas and a proper running ducati in the new year.

[RideWithStyles]

Well I’d agree - If the ally express is only that much I’d do it anyway, one thing for sure you’ll be one step closer to knowing if it is potentially the tps for extremely nothings assuming of course that ally part is correct and working?

 

If it changes anything , even if doesn’t work fully but does something different for you then you know something either wholely or partially to do with it prior and after in the system to that part! so one step closer. 

Plus it might take a while to get to you over the season.

[Hairsy]

This really IS the last update for now! I had a bit of time yesterday so I had a go at tuning the bike.

 

A bit of a nerdy update and I don't know how interesting this level of detail is, but it's nice to have a record of what I've done for my future reference.

 

Firstly one for the detail people - the TPS readings that I was getting at the bottom of its range were on my mind so I wanted to see whether it was reading consistently across the rest of the range. I produced this graph using the diagnostics

 

 

The green line is the mV reading coming from the sensor (scale is from 0 to 5v). The purple line is the degrees of throttle opening that the ECU is interpreting from that mV reading.

 

I attempted to slowly and smoothly open the throttle to give a nice consistent line. You can see that on the second time I sped up a bit at the top but the graph still works.

 

There is a 'knee' in the green line. This is entirely expected - the TPS on this bike is a Non Linear model and operates on two different scales depending how far open the throttle is.

 

What's important is that, as the throttle opens, the purple line should be smooth and there should be no glitches or points at which it drops out or spikes. As you can see, it all looks perfect. The ECU is expecting the knee in the green line and is accurately interpreting it and producing a smooth purple line.

 

So this leaves me feeling that the TPS should be OK. However, it doesn't satisfy me completely because when I was resetting the position for the bottom of the range, the reading just didn't seem quite right. And, of course, the problem I'm having with the bike is stalling when it drops to idle - which is right at the bottom of the range.

 

I'd hoped that this test might show something bad because it would give me a source of a problem. I think it points to the TPA probably being OK but it's probably inconclusive.

 

Anyway, on to the tuning.

 

My very good friend who owns the carbtune gave me permission to butcher the adapters so I got the dremmel out and adapted them to fit my bike. I initially hooked everything up to the carbtune unit but actually the rods in it were a bit sticky so I reverted to some vacuum gauges. I'll give the carbtune a service for him as a thank you!

 

I spent a good half hour getting the balance to a reasonable state. It was definitely out but, at least to some degree, that could have been caused by me as I was setting the TPS. 

Everything I've read says that balance on these bikes is very much a compromise - if you get it good at one rpm then it will go out on another. However I was reasonably comfortable with where I ended up.

 

I then moved on to setting the mixture by adjusting the air bleed screws and ECU mixture trim to get as stable as possible idle. This is beery difficult when I don't have any way to monitor exhaust gas. I had to keep adjusting them to achieve the smoothest possible idle. Of course as soon as you adjust one, it then has an impact on others. In the absence of the right equipment, I only have this option of trial and error.

 

Once I'd finished, the outcome was a definite improvement and I could regularly give the bike a rev and have it settle back down to an idle - it hasn't done this before. However, the fundamental problem of it dying after revving remains.

 

 

And then, finally, I noticed that there was a weird pressure build up in the tank causing fuel to be pushed up the drain hose (the one that's intended to pick up any fuel if you slightly overfill the tank) so I drained the tank off. After doing this, I noticed that a hose had come off near the pump - annoyingly I don't know whether this was the actual problem or whether I'd caused this when I was using my jiggle syphon to empty the tank. The hose in question is one that's normally just a friction fit. I opened up the tank again (I'm getting quite quick at that) and the only problem I could see was that loose hose. I refitted it but also added jubilee clips to that and one other hose that is just a friction fit.

 

I then put everything together again and put fuel back in the tank. As has been the case every time I've worked on the bike, it took quite a long time to get it started again. Once started, it runs fine even if I've left it for a while. I've always put this down to a design issue with priming the pump when it's been completely empty. But I'm starting to wonder - could it be that this is a sign that the pump isn't very good?

 

So I'm left with a number of thoughts:

 

- A number of things I've done have improved matters - particularly cleaning the injectors, replacing the fuel filter and balancing the throttle bodies

- However, I still haven't solved my problem. I think this is likely the result of working on a bike that's been left for a long time unused - more than one problem has developed of the 13 years of sitting doing nothing

- I don't have confidence in my mixture settings

- The TPS looks good in the range it's operating but still behaved oddly in the initial setup so remains a niggle in the back of my mind

- I still don't have full confidence in the fuel supply - was my weird problem today caused by the hose that I've now replaced or did I dislodge that hose while investigating? And is the priming 'issue' and issue? Or just normal?

- If I didn't care about money I'd be putting in a new TPS along with a new fuel pump & inlet filter (which is separate to the main fuel filter). But I can't just throw parts at the bike. 

 

All a little unsatisfactory.

 

As I'm now taking a bit of a break for Christmas, I've ordered a couple of things:

 

1) A cheap TPS - got to be worth a try. As RideWithStyles pointed out, it will be useful to see whether it changes anything.

2) A fuel pressure tester - this should help me to understand whether I do have a problem with fuel pump etc.

 

And that really is it for now - Happy Christmas.

[Hairsy]

Back to the bike today. My latest AliExpress order arrived this morning including a new Throttle Position Sensor and a fuel pressure tester. Both very cheap and of dubious quality. As you'll read about in a moment ...

 

First job was to test the TPS and make sure it had the dual rate resistance that the original has - and it did. In fact it behaved identically to the original. My concern with the original was that its lowest voltage reading is a touch higher than expected but the new one has exactly the same lowest reading. My conclusion here is that perhaps the reference voltage is slightly high on this bike (we're talking 176 mv instead of 150mv). 

 

I installed the new TPS but while setting it up I realised that when the throttle is opened and closed, it's not landing on exactly the same voltage every time. Again, tiny fluctuations but the original didn't do this. I concluded that trying the replacement has shown that the original is actually working OK - and in fact it's slightly better. So I decided to revert back to the original and refitted it.

 

Having disturbed everything to reset the TPS, I then needed to repeat the setup of the throttle bodies. This went OK initially but when I tried to balance them it proved impossible. If I adjusted the balance enough for the right throttle body, it was causing the linkage to increase the left throttle body idle. I'm not going to try to describe what was happening but I knew it had to be something mechanical in the linkage that wasn't behaving.

 

There was no choice but to remove the throttle bodies and inspect the linkage. I disconnected throttle and fast idle cables, fuel and electrical supplies to the injectors and the electrical connection to the TPS. I could then loosen a couple of jubilee clips and remove the throttle bodies.

 

 

On initial inspection, I could see that the right butterfly wasn't closing properly - it was only a tiny bit more open than the left but that's enough to throw out the balance. What I couldn't figure out was what was stopping it close. As an initial starter-for-10 I cleaned up all of the moving parts because some of them had a layer of dirt and grease on them. There really wasn't very much but a little bit. And that proved to be enough to resolve the problem - there must have been a bit of friction somewhere. I still don't really know what exactly was happening but after the cleaning I was able to adjust the balance on the bench to be visually good.

 

I then put everything back together and started the bike - and the balance was great - it could perhaps benefit from a very tiny tweak but it's certainly close enough that it isn't going to be causing a running problem. The downside is that although it was running a little better, it was still dying sometimes when settling back to idle after revving.

 

On to the fuel pressure testing. I drained the tank and have temporarily fitted some quick release connectors into the fuel return hose to the tank. This enables me to easily attach and remove the pressure tester. When I eventually am happy then I'll remove the quick release connectors.

 

 

At this point, I should say that I'm quite nervous about using cheap tools like pressure testers from AliExpress. I certainly can't expect them to be super accurate but my hope is that they'll give me enough of an indication of what's happening that I can take decisions.

 

So I connected the pressure tester and put a couple of litres of fuel into the tank. Every time I've previously emptied the tank and then re-added fuel, small amounts of fuel have been insufficient to get the bike to start. Sure enough, the pressure reading was showing around 1-2 psi and the bike wouldn't start.

 

I added another 5 litres and tried again. Once again, 1-2 psi and no starting. I've no idea, at this stage, whether the pressure tester is even working. On previous occasions, leaving the bike for a while has sorted out starting issues so I went and did a domestic job for an hour and tried again.

 

This time, after 2 more primes, the pressure shot to an indicated 100 psi. Small panic ensued (I was hoping for around 60 psi) but nothing seemed to be leaking so my thought at this stage was that the cheap gauge was reporting some decent pressure but was over-reading.

 

I then started the bike and monitored fuel pressure. Remember - this is indicated levels but I very much doubt they're accurate. What's interesting is the changes to the pressure as the bike warmed up. I'm no fuel injection expert but I was expecting pressure to be fairly constant if everything was working OK. What I got was:

 

Engine Cold : 100 psi at idle (1,100 rpm) - slightly higher when revving

150 degrees F : 92 psi at idle (didn't take a reading while revving - idiot!)

170 degrees F : 90 psi at idle, 95 psi at 2,000 rpm

207 degrees F : 88 psi at idle, 95 psi at 2,000 rpm

 

When the bike cut out, the pressure would drop away quickly but I really can't tell whether the pressure is dropping to cause the stall or the stall is causing the pressure to drop.

 

For now, I'm ignoring that actual reading of 100psi - I think that's inaccurate but I'm interested in the relative levels

 

So advice needed please if anyone is familiar with working with fuel injection pumps : is it normal for fuel pressure at idle to reduce by just over 10% from cold to fully warmed? I don't know whether it's temperature that's causing this or just the amount of time the pump has been running but it's definitely reducing.

 

I have one more test that I want to do tomorrow - I want to add more fuel to the tank. That should make the pump's job a bit easier. I'm not optimistic that it will make a difference but if it did get rid of the problem then I would feel more confident that the pump is the issue.

 

If that doesn't work then I'm really not sure what to do. I still have a gut feel that the fuel supply is my issue but the previous owner told me that they'd replace the pump recently. The biggest reason to suspect the pump is that it doesn't seem to manage to prime itself when I first put fuel in there - it needs to be left a while. I can only assume that fuel is working it's way through the pump while it sits but I really don't think it should need this.

 

If I did decide to replace the pump then there's quite a range of prices - Ducati is around £203. Unbranded alternatives range from around £30 to £100 but I've no idea on the quality - my guess would be that they all come from the same place in China and its just the seller's markup that varies. The Bosch equivalent pump is a 69238 model and I could do some research to see if I can get one of those for a reasonable price.

 

I have to admit to being a little confused about what to do next - and a bit fed up. If I knew for certain that the pump was my issue then I'd bite the bullet and do it - but I'm far from certain. I can't throw parts at the bike in the hope of finding the problem - I haven't got the money to throw away.

 

So I'll see how it goes tomorrow with more fuel in the tank and then give it some more thought.

[Simon Davey]

Wow, that was quite a day. 

You might not feel so positive, but you're one day closer to the fix!

[Mickly]

13 hours ago, Hairsy said:

Back to the bike today. My latest AliExpress order arrived this morning including a new Throttle Position Sensor and a fuel pressure tester. Both very cheap and of dubious quality. As you'll read about in a moment ...

 

First job was to test the TPS and make sure it had the dual rate resistance that the original has - and it did. In fact it behaved identically to the original. My concern with the original was that its lowest voltage reading is a touch higher than expected but the new one has exactly the same lowest reading. My conclusion here is that perhaps the reference voltage is slightly high on this bike (we're talking 176 mv instead of 150mv). 

 

I installed the new TPS but while setting it up I realised that when the throttle is opened and closed, it's not landing on exactly the same voltage every time. Again, tiny fluctuations but the original didn't do this. I concluded that trying the replacement has shown that the original is actually working OK - and in fact it's slightly better. So I decided to revert back to the original and refitted it.

 

Having disturbed everything to reset the TPS, I then needed to repeat the setup of the throttle bodies. This went OK initially but when I tried to balance them it proved impossible. If I adjusted the balance enough for the right throttle body, it was causing the linkage to increase the left throttle body idle. I'm not going to try to describe what was happening but I knew it had to be something mechanical in the linkage that wasn't behaving.

 

There was no choice but to remove the throttle bodies and inspect the linkage. I disconnected throttle and fast idle cables, fuel and electrical supplies to the injectors and the electrical connection to the TPS. I could then loosen a couple of jubilee clips and remove the throttle bodies.

 

 

On initial inspection, I could see that the right butterfly wasn't closing properly - it was only a tiny bit more open than the left but that's enough to throw out the balance. What I couldn't figure out was what was stopping it close. As an initial starter-for-10 I cleaned up all of the moving parts because some of them had a layer of dirt and grease on them. There really wasn't very much but a little bit. And that proved to be enough to resolve the problem - there must have been a bit of friction somewhere. I still don't really know what exactly was happening but after the cleaning I was able to adjust the balance on the bench to be visually good.

 

I then put everything back together and started the bike - and the balance was great - it could perhaps benefit from a very tiny tweak but it's certainly close enough that it isn't going to be causing a running problem. The downside is that although it was running a little better, it was still dying sometimes when settling back to idle after revving.

 

On to the fuel pressure testing. I drained the tank and have temporarily fitted some quick release connectors into the fuel return hose to the tank. This enables me to easily attach and remove the pressure tester. When I eventually am happy then I'll remove the quick release connectors.

 

 

At this point, I should say that I'm quite nervous about using cheap tools like pressure testers from AliExpress. I certainly can't expect them to be super accurate but my hope is that they'll give me enough of an indication of what's happening that I can take decisions.

 

So I connected the pressure tester and put a couple of litres of fuel into the tank. Every time I've previously emptied the tank and then re-added fuel, small amounts of fuel have been insufficient to get the bike to start. Sure enough, the pressure reading was showing around 1-2 psi and the bike wouldn't start.

 

I added another 5 litres and tried again. Once again, 1-2 psi and no starting. I've no idea, at this stage, whether the pressure tester is even working. On previous occasions, leaving the bike for a while has sorted out starting issues so I went and did a domestic job for an hour and tried again.

 

This time, after 2 more primes, the pressure shot to an indicated 100 psi. Small panic ensued (I was hoping for around 60 psi) but nothing seemed to be leaking so my thought at this stage was that the cheap gauge was reporting some decent pressure but was over-reading.

 

I then started the bike and monitored fuel pressure. Remember - this is indicated levels but I very much doubt they're accurate. What's interesting is the changes to the pressure as the bike warmed up. I'm no fuel injection expert but I was expecting pressure to be fairly constant if everything was working OK. What I got was:

 

Engine Cold : 100 psi at idle (1,100 rpm) - slightly higher when revving

150 degrees F : 92 psi at idle (didn't take a reading while revving - idiot!)

170 degrees F : 90 psi at idle, 95 psi at 2,000 rpm

207 degrees F : 88 psi at idle, 95 psi at 2,000 rpm

 

When the bike cut out, the pressure would drop away quickly but I really can't tell whether the pressure is dropping to cause the stall or the stall is causing the pressure to drop.

 

For now, I'm ignoring that actual reading of 100psi - I think that's inaccurate but I'm interested in the relative levels

 

So advice needed please if anyone is familiar with working with fuel injection pumps : is it normal for fuel pressure at idle to reduce by just over 10% from cold to fully warmed? I don't know whether it's temperature that's causing this or just the amount of time the pump has been running but it's definitely reducing.

 

I have one more test that I want to do tomorrow - I want to add more fuel to the tank. That should make the pump's job a bit easier. I'm not optimistic that it will make a difference but if it did get rid of the problem then I would feel more confident that the pump is the issue.

 

If that doesn't work then I'm really not sure what to do. I still have a gut feel that the fuel supply is my issue but the previous owner told me that they'd replace the pump recently. The biggest reason to suspect the pump is that it doesn't seem to manage to prime itself when I first put fuel in there - it needs to be left a while. I can only assume that fuel is working it's way through the pump while it sits but I really don't think it should need this.

 

If I did decide to replace the pump then there's quite a range of prices - Ducati is around £203. Unbranded alternatives range from around £30 to £100 but I've no idea on the quality - my guess would be that they all come from the same place in China and its just the seller's markup that varies. The Bosch equivalent pump is a 69238 model and I could do some research to see if I can get one of those for a reasonable price.

 

I have to admit to being a little confused about what to do next - and a bit fed up. If I knew for certain that the pump was my issue then I'd bite the bullet and do it - but I'm far from certain. I can't throw parts at the bike in the hope of finding the problem - I haven't got the money to throw away.

 

So I'll see how it goes tomorrow with more fuel in the tank and then give it some more thought.

Having recently had issues with the fuel pump on my FI KTM ( the pressure was intermittent due to it and its strainer being totally bunged up with rust & sludge ), I learned a couple of things… one test is to remove the whole pump assembly from the bike drop it into a bucket of petrol, plug it in ( or provide a power source - dodgy because of potential sparks) and ensure it’s all working as it should - i.e it primes, there are no splits or cracks in the the pipework or inline filter (if it has one) also that the fuel filters are clean. 
On my bike the fuel pump should kick out about 100psi, however there is a fuel pressure regulator that bleeds off a lot of this to bring it down to around 48-52 PSI, so it might be worth checking out the values for your bike & see if that fuel regulator is working.

 

[Hairsy]

Well today was eventful.

 

I spent some time yesterday evening looking at fuel pump options. I was feeling fed up and was almost ready to just order one out of desperation if I could find something of decent quality for a decent price. But I couldn't so I didn't.

 

I started today by filling the tank with fuel to give the pump an easier job. This, I theorised, might convince me to order a new pump with confidence that it was my problem. The outcome - it made no difference at all to fuel pressure readings or to the stalling-after-revving problem.

 

So I then revisited the fuel pressure readings. The readings yesterday just seemed odd. I know that a cheap tool isn't going to be 100% accurate but readings of 100psi are double what I'd expect and my experience with these sorts of tools is that they're not perfect but they're not terrible. I lifted the tank ...and immediately spotted a problem. As a result of squeezing in the additional hoses and T piece for plumbing in the fuel pressure sensor, the final hose in the system that returns fuel to the tank (and the pressure regulator) was being squashed. Total schoolboy error - I immediately tried a quick prime of the fuel pump (with the tank still up and the hose not squashed) and the pressure went directly to around 50 psi and stayed there.

 

 

It was too early to work out whether this might result in good, bad or indifferent news but at least it gave me an incentive to move forward - and I really needed one. I reworked the hose routing so that I could put the tank back down without crushing any hoses. I then started the bike and found that the reading was a solid 51 psi. Revving the bike didn't change it at all - it was solid all the way from idle to high revs. I let the bike warm up fully and by the time it was hot the pressure had dropped to 50 psi. I checked the manual and that says 3 bar (44 psi) so the readings are now within 'expected inaccuracy tolerance' of the cheap pressure tester.

 

Not surprisingly though, this didn't make any difference to how the bike ran. However an interesting observation is that is was running just as well as it did yesterday when it was getting c.100psi at the injectors. I guess the injectors themselves have a limited flow rate and so the increased pressure yesterday wasn't actually having a significant impact.

 

So my conclusion at this stage is that I definitely have a solid fuel delivery system - with the added benefit of knowing that the pump is capable of sustaining almost double the required pressure.

 

So good news - I don't need to buy a fuel pump.

 

But bad news - I'm back to square one and don't have a clue what the problem can be.

 

Upon this realisation that I've run out of suspected problems, I was close to breaking point. But I decided to have one more go at running the bike with the diagnostics, vacuum gauges and fuel pressure gauge all attached and to try to watch what's happening as if I was seeing the bike for the first time. Forget all my previous ideas and just observe and be patient.

 

So that's what I did - I tried different rates of revving the bike, fast & slow idle, letting off the throttle quickly, letting it off slowly, holding revs for a bit before dropping - everything I could think of. As before, it would sometimes settles to an idle Ok but more often would stall. All the diagnostic parameters looked completely normal, the vacuum gauges gave no hint of a leak, fuel pressure was consistent.

 

And then I spotted something. Occasionally, the stall would happen at slightly higher revs and when it did I could see that the rev counter would drop to 0 faster than the revs were dropping. The revs might take half a second to drop from 3,000 to 0 but the gauge went to 0 in an instant. I repeated it a few times and it did it every time.

 

The Crank Position Sensor on this bike is used by the ECU to determine fuelling AND is also used for the rev counter. Could it be that the sensor is failing, telling the ECU that the engine has stopped and cutting fuel. I was encouraged to have a new theory - but at the same time I wasn't yet convinced because I wasn't getting any fault readings from the sensor. And that should happen with a failing sensor.

 

I then remembered reading that that this engine can be very sensitive to the position of the Crank Position Sensor and that there are shims available to adjust it. In fact, when I first got the bike home, I'd actually tried to remove the plug from the engine that allows the gap between the sensor and flywheel to be checked. I'd found that plug had an allen head and it was very tight. I'd decided not to pursue it for fear of creating a problem I didn't need. However, I'd given it a spray of Plusgas a few times since then, just in case I might one day need to access it.

 

So, while the engine was still hot from running, I gave it another spray of Plusgas and then got an allen wrench on it again and this time it released. This was followed by 15 minutes of creative language as I fought with the tiny amount of access to the allen head which made it impossible to get a wrench turned 1/6th of a turn - along with a previous person's healthy application of loctite.

 

Eventually I got the plug out - only to find that the hole that it left was too small to get my feeler gauges into. However, I remembered that I have a set of needle gauges in the house (that I use to set up guitars) so they got promoted to bike duties. The air gap that I needed is 0.6mm to 0.8mm - and I actually had 1.4mm.

 

Now I'm starting to get excited. If the gap's too big then that would likely cause an irregular reading but this could potentially happen without the ECU finding any fault with the sensor. It would just think that the engine had stopped.

 

So I removed the sensor, along with yet more loctite and a load of hardened sealant stuff that someone had applied. This part shouldn't need any sealant as it has an O ring - but that was also caked in sealant. So the first thing was to clean up the sensor, the shim that was already fitted and to fit a new O ring.

 

 

I then refitted the sensor in the misguided hope that cleaning it might have given me the extra reach I needed - sadly the cleaning had given me only 0.1mm of the 0.7mm I needed. I then removed it again and checked the thickness of the shim - 0.6mm! So removing the shim would take me to a gap 0.7mm - exactly in the middle of the range I need.

 

Now I'm really getting excited.

 

So back on with the sensor, reconnect everything, start the bike up and ...

 

 

I cannot tell you how happy this makes me. Weeks of chasing fuelling issues, including solving some genuine issues along the way but finding that none of those issues were my main problem. And finally it comes down to a 0.7mm air gap.

 

So I was right that it was a fuelling issue but I never thought that it was a 'mechanical issue with an electronic sensor'. With the benefit of hindsight, the one thing I probably should have done was to spend more time just watching all of the parameters while the bike ran and try to spot something odd. However, that's easy to say when you've been this far down the road - I suspect that I had actually observed that weird rev counter behaviour but it just hadn't occurred to me that it was significant.

 

Anyway - I'm now in a good mood as I can start work on the chassis mechanicals. The wheels and brakes will be coming off so that I can deal with any issues there and to give me good access to clean everything up and check the chassis. New tyres are essential as the current ones are ancient. She'll probably get a set of Pirellis in honour of the Italian heritage.

 

And then there needs to be a decision on bodywork - I think I'll leave paint marks & chips initially and get the bike running and on the road so that I know my final costs. I can then consider whether to just apply touch up paint to the body work or get a quote for some professional intervention. That will all depend on whether it can be done within the final value of the bike.

 

But, for now, I have a really important job - I'm having a beer.

[Mickly]

[Simon Davey]

I hate to admit to being a big softie, but I've literally got tears in my eyes.....

That is so darned good to read, and she sounds so sweet in the video. 

 

That's @Hairsy & @Mickly have scored 100% in getting bikes running.

Nice work boys, and a lesson or two for the rest of us.

 

[Old-codger]

Great news you got to the bottom of it congratulations have another beer. 

[Shepherd]

Most of what you did went right over my head, but man, I enjoyed the reading of this.

Great result, and well deserved just for the perseverance alone. I'm with OC - have another beer.

Edited January 3 by Shepherd
Spellchecker

[Hairsy]

1 hour ago, Shepherd said:

Most of what you did went right over my head

 

Honestly, nothing I did was clever. The reason I document these projects is so that, hopefully, others will give it a go. I have to say that this one has stretched my patience to breaking point but if you choose the right bike then it's just a case of being methodical - and not being afraid to ask silly questions and / or mess up.

 

We should have more resto threads on here - they're great fun and I feel sure that there's loads of people who can do it. You just need to be careful with the choice of bike. It took me months to find one that was realistically priced for the amount of work that was required - most are grossly overpriced but there are good ones out there.

There's still loads more work to do so this thread has plenty of life left in it yet - I just hope that the rest of it goes more smoothly than the first few weeks did.

Edited January 3 by Hairsy

[Hairsy]

After weeks of angst, a nice easy day. Not completely successful but still easy.

 

First job was to remove the front brake calipers so that I could give them a clean. I first wanted to check whether the pistons were corroded in which case I'd disconnect the brake lines and work on them on the bench. However, the pistons are all in excellent condition - I can't see a mark on them and all 8 can be pushed in with just finger pressure. I think that's the first time I've seen brakes in this good condition on a project. So the calipers got a clean in-situ, just hanging from a bit of bungee. It's not quite a good a job as they'd have got on the bench but I'll give them another going over once everything is bolted up.

 

 

I then gave all the brake hardware a clean - bolts, pins, split pins, pad springs and pads. All had a layer of brake dust but were in great condition underneath. The pads have a decent amount of life left in them and the friction material is in great condition so they just got a spray with brake cleaner.

 

My next plan was to remove the front wheel - where I met my first hitch. The front wheel needs a 28mm socket and I don't have one. Looking at local places, no-one has one available and it seems to be an uncommon size. There are lots of socket sets available going up to 30mm but none of them include 28mm. So I now have one on order.

 

So a slight change of plan and I moved my attention to the headlight. These bikes are not known for the brightness of the headlights and the headlight was looking a bit dull. So I removed it, took it apart and cleaned the reflectors and the lens itself. The difference afterwards was striking and should deliver a significant improvement.

 

 

Next was a simple bit of cleaning of the instruments and they came up nicely. However, a previous owner has had the clocks off before, I suspect to try to replace the LED for the alarm - which they failed at. And I'm starting to see a clear pattern emerging - whenever I find something that's been worked on, I find evidence of someone who is paranoid about things coming loose. This time I didn't find loctite (a pleasant change) but I did find that a rubber bolt thingy had been overtightened and had been broken. This part is just there to absorb vibration for the instruments and it isn't under great stress. So I'm hoping that an epoxy repair of the rubber will save me having to source a replacement - I'll see tomorrow how strong my repair is.

 

 

And finally for today, I wanted to try to deal with the corrosion on the aluminium surface of the brake and clutch levers. I suspect this is caused by poor quality anodising. I initially tried cleaning them up but although there was a small improvement, I wasn't particularly happy. I then made the discovery that the underside of both levers was in much better condition than the top surface - and that the brake and clutch levers are identical.

 

So I swapped them over and now have the poor anodising underneath, where it can't be seen. The picture shows the clutch lever now being located on the brake side and the previous brake lever for comparison. These are the kinds of discoveries that really help when working on a budget.

 

 

And finally for today, I've removed the caps for the brake and clutch master cylinders and have stripped back their chipped paint. I'm half way through priming and then spraying them matt black. Before and after pictures to come tomorrow.

 

So overall a nice simple day - I like days like this.

[Mickly]

Poor anodising can be removed (carefully) with caustic soda, leaving a great surface for painting, lacquering or re-anodising depending upon your ability.

[Hairsy]

5 minutes ago, Mickly said:

Poor anodising can be removed (carefully) with caustic soda, leaving a great surface for painting, lacquering or re-anodising depending upon your ability.

 

I didn't know that - thanks.

 

Although I had a quick look on YouTube and suspect that it could be a dramatic effect!

 

 

[Mickly]

1 minute ago, Hairsy said:

 

I didn't know that - thanks.

 

Although I had a quick look on YouTube and suspect that it could be a dramatic effect!

 

 

Yep, but starting with a relatively weak solution would probably be advisable

[Hairsy]

Master cylinder caps done.

 

[V650]

Making great progress there

Well done

[Hairsy]

Not much progress today due to a silly schoolboy error.

 

My plan was to bolt the instruments back in place with my newly repaired rubber mount and then refit the gleaming headlight. The rubber mount repair was successful and the mount now appears really strong. I started to put it back in and then just thought to myself "If the guy did his gorilla thing when tightening this mount, I should probably check the other two". Sure enough, although they hadn't actually broken completely apart, they'd been overtightened and the rubber was coming away from the metal. They definitely wouldn't last much longer as they were.

 

So it was out with those other two mounts and the epoxy and now it's another 24 hour wait for the new repairs to dry. Not a big problem but a bit silly of me not to check yesterday when I found the first problem.

 

One other little thing today. I wasn't completely happy with my cleanup of the calipers yesterday. As I often do, I woke in the night thinking about the project and remembered that I've had great results in the past cleaning calipers with neat MucOff and a soft brush. So this morning I gave that a go and now they're much better. First picture below is how they looked yeterday after using brake cleaner and metal polish. Second picture is after today's MucOff. It's really brought the colour out. Much better.

 

[Simon Davey]

Quite a difference considering your already cleaned them. I have an unopened can/bottle of MucOff, not for long.