Lack of power from idle - around 2.5K RPM.

[Guest]

On Sunday I am looking to get to the bottom of this and just compiling a checklist of most likely causes before I give up and spend a few hundred putting it into a garage...

It's absolutely fine once I'm moving, just when I'm going slow - filtering is a bit annoying as is going round slow corners. There is also a slightly rough idle, starting the bike always takes a good 5 seconds or so before it's at a point where it won't cut out & I have noticed a bit of backfire upon declaration. I appreciate these symptoms may not relate to each other, I'm just listing what I feel could be helpful to know.

So far I've checked;

Air filter - fine.

Carb sync - fine (see video below for result).

Fuel tank vent hose - fine and connected.

Vacuum test video (sorry - I give up posting from youtube to here!)

http://youtu.be/nwgHVJZG_a8

Valve clearance

Spark plugs

Manifold for any leaks

...Is there anything you would add to the likely causes whilst I'm making the list???

Current mileage; 25K

Bike; 1999 R6

Cheers,

Phil.

[Mr Fro]

Sounds like you're on the right track. Those symptoms could well be linked.

Asking decent power from 2.5k on an R6 is expecting a bit much to be honest!

From your vid - what is your idle speed? Sounds a bit high to me - might be worth setting it a bit lower (~1k) and see what it's like then.

2.5k is pilot jet territory so I'd be stripping the carbs down and giving them a good clean and squirt with some carb cleaner, making sure you make a note of all the current carb screw settings and then setting them back to the manufacturer specs when you're done (POs are great at buggering things up).

Let us know how you get on!

[Tango]

How's the exhaust? Any leaks around that? Check headers.

Are you sure that there's no leaks on the inlet stubs? Have a spray around with WD40 with the engine idling and see if the revs rise.

And, as Mr Fro says, the carbs may need a clean.

[Guest]

Idle is around 1400, this is close to what the manufacturer manual suggests...

Had a look in the haynes and actually don't fancy the valve job - that looks cumbersome. If I can't find it by other means it will go for a full service, someome else can do that ball ache.

The thing is, sometimes there's just no response, it chugs away and after a couple of seconds the power kicks in so it's not that I'm asking a lot from it some it kicks in...

So jobs to do that may find the problem but won't be such a nuisance...

-Check for leaks in exhaust.

-Plugs.

-???

[Guest]

This is a nightmare situation...

I took the tank off, air box out, then trying to get to the spark plugs was so difficult I only managed to see 2

After spending 3 hours on it i gave up. Put it back together and now the bike won't start

The fuel pump doesn't come on anymore like it used to when the bike is turned on... I have a sneaky suspicion the wores have been damaged.

[Tango]

Nightmare....

Whip the tank off again and make sure the connections to the fuel pump are good and there's no trapped or cut wires.....

[Guest]

Just to update;

Last night there was a fuse that had blown. Replaced it but no joy, still cranking and not starting.

Today, everything came out and back in again, went to start, battery went flat.

I gave it a few mins, switxhed on, saw the lights were on... that's strange... no hope at this stage, pushed the start button and I could hear it wanted to go. Gave it some throttle and bang! It started!!!

Not only did it start, but I went out for a ride and my 1st gear low RPM problem was solved!?

I wish I knew what I did so I could update the thread and help someone else but I don't! The only thing I could think of, why the bike wouldn't start last night is that when the carbs were lifted it created an air pocket somewhere, or maybe there was no fuel anywhere to ignite maybe and it needed to be pumped in...

Anyway, I have no idea why or how but the bike is running 100% fine now.

How bizarre is that?!

[Stu]

Sounds a lot like fouled plugs to me

They can have the same affect and take a while to clear

[Guest]

Update:

Well... the day I got it going, I had no problems. The next day it was back to it's annoying self

I did manage to find something out though... Took a look at the dipstick - oil was over the maximum level, probably been like this since I "topped it up" around 600 miles ago. There's no visible oil leaks but I believe some has got into the combustion chamber and caused the spark plugs to get a bit grubby - pictures below, what do you think? ...Maybe they're just not in the best condition...?

So today I drained the oil and made sure it is now at the right level. I will order some new plugs, clean the wells and have high hopes of that solving the hesitation issue.

[Chrissb6]

The plugs look fine by me Mate. Always measure out the oil on a oil change check the manual. Make sure the bike is upright and level and not on it's side stand. Initial fill, fill until you see oil in the sight glass. Then fire her up for a minute or 2 no need to rev it, this will fill up the oil filter and charge the system. Then stop let the motor let it rest. Then recheck your levels and check for leaks, never over fill between the high and low markers on the sight glass is fine. And as said, always make sure the bike is upright and level when you check the levels. Stay safe

[Stu]

pretty sure the R6 doesn't have a sight glass I'm sure they are a dipstick

[Chrissb6]

pretty sure the R6 doesn't have a sight glass I'm sure they are a dipstick

Stick or glass Stu same rules apply.

[Stu]

this is true chris

just thought I would clear it up rather then him looking for a sight glass if there isn't one

[Guest]

Yeah there's no sight glass.

Plugs look ok?? What about the white bits? Isn't that fouling???

[Stu]

fouling is black sooty/oily deposits

this stops the plugs sparking properly

I would replace the plugs while they are out if you havent already done so or at least clean them up

[Guest]

And the trophy goes to........

Mr Fro (well sort of).

All these weeks I've been struggling with the low rpm power and you know what gave it life again?!

A bit of radex!!!

Fuel filter is on the way and getting changed as well be yeah... looks like the problem was crud in the fuel system. I thought of it the other night when I saw how long sparks last for before needing a change and mine were last changed around 10k miles ago...so probably good for another 50k!

Poored in last night, instantly better for my ride home.

This morning when cold it went back to being around 50% better but once it was warmed up and the radex was flowing, 100% better for 100% of the time.

[Guest]

Remember this problem!? I never fixed it - just didn't update until I knew what the problem was.

UPDATE:

Turns out to be 1 of the ignition coils being faulty. It went to the mechanics to have that diagnosis. Of course they also cleaned the Carb but I'm not convinced of that being the any kind of problem since both the air and fuel filter were clean and in perfect working order!).

Anyway, they reckon I'll have it back tomorrow so will be able to test over the weekend.

[Guest]

Problem solved!

The technicians report listed 3 things as what they did to solve it:

1: Cleaned and synced the carburetor. This apparently made the mid range better but there was still a miss-fire at idle.

2: Replaced no.3 ignition coil.

3: Balanced carbs (which I find strange based on my testing...)

Engine is now smooth as my pet ferret's coat!

[Stu]

why do you find 3 strange?

the thing that stands out to me is syncing and balancing the carbs are the same thing

balancing the carbs does help a lot low down in the rev range especially off idle but if you had a dodgy coil then this will be most of your cause

[Guest]

I find it strange that I tested it and they were all in sync.

Maybe they got out of sync as the ignition coil progressed to fail?