New Motorcycle Shaped Object..

[Tinkicker]

I will be picking up my next victim on Saturday.  99% complete 1977 Yam DT100 in good original, unsullied condition and a runner.  Less than 2800 miles on the clock.

Needs battery, indicators, exhaust baffle, mirrors and front sprocket cover.

 

Back in the day when I worked at a large motorcycle project, we had 8 RT100s on fleet, running 7 days a week off road.  RT100s are identical to the DT100 apart from no road electrics and different bodywork. Engine and all cycleparts are exactly the same, so I know them like the back of my hand.

 

I will be taking lots of pics of the restoration for its provenance folder, so if anyone is interested in a DT100 based rerun of my  DT175mx restoration, sing out.

 

77 DT100. It came into my posession rather unexpectedly.  I am still reeling from the shock.

 

 

 

RT100 is its off road only brother.

Edited August 1, 2023 by Tinkicker

[Tiggie]

You can keep these restorations coming every day for me! 

[Tinkicker]

OK.  Picking it up on Saturday from Chester le Street.  I will kick off the thread with a few pics as it arrived. 

It will not be done to concours standard like the 175 as the DT100 was never that popular in the UK and I doubt it will ever be classed as desirable, however it deserves preserving and a going through.

 

Not quite sure exactly what standard it will get, I will certainly not be spending £1000 on show quality paintwork and many £100s spent on genuine factory nuts and bolts, but it will certainly be pulled apart to the last nut and bolt, cleaned, repainted as factory spec.

 

Tentative plan of works.

 

Wheelbearings and brakeshoes - tick.

Chain and sprockets - tick.

New cables throughout- tick.

Frame and cycleparts beadblasted and repainted - tick.

Dents pulled and tank repainted and clearcoated (rattle can) with fresh decals - tick.

Forks stripped and refinished and with new stanchions and seals if chrome pitted- tick

Any electrical work on main loom and electrical system to repair and restore back to factory spec if someone has bodged it over the years - tick.

Rusted bolts replaced with stainless-tick.

Bore examined and piston rings replaced - tick

Crank seals replaced - tick.

Missing parts sourced and replaced -tick.

 

Anticipated completion date - Xmas.

 

It should end up being an original looking, presentable, reliable and almost new looking bike to the casual observer, however it will never fool a knowledgeable show judge.

 

Unless I get carried away with it like I did with the VFR and the 175.  

 

Certainly not to my DT175 standard (I hope).  That would cost five times its end value....and my marriage.

Edited August 2, 2023 by Tinkicker

[GojuRyu5]

Whoa, that DT175 looks immaculate!  Something to aspire to.

[Tinkicker]

Well I got her home last weekend and had a bit of time to take stock of wnat I have bought.

 

She has a genuine 2738 miles on the clock.  She is still fitted with her original 1977 tyres front and rear.  Badly cracked though as one can imagine.  What a shame.

Chain and sprockets are original.

She starts very easily and sounds very sweet.  However she idles really fast because the throttle cable is broken at the adjuster.

The clutch plates are stuck.  Not a great thing to find when the engine is revving away to itself and you bang it into gear. 

Thankfully, I was sat on the bike covering the front brake at the time, otherwise I think it would have crashed through the patio doors and joined the missus on the living room sofa.

The fork legs are bent.  Wonder if it is related?

Tank is dented, but they look like they will pull with hot glue puller fairly easily.

All indicators and the rear indicator stays are missing.

Engine sprocket cover is missing.  I can source a new one from Thailand.

Fitted new battery and nothing.  The electrics are dead.  I think it is the ignition switch.  It does not feel good at all.

Fuel tank looks sound and in good condition inside. A little discolouration, but no rust.

 

 

True mileage. Dead switch.

 

Rare as hens teeth, US spec sealed beam unit.  It looks brand new but judging from the dust on it inside, is not.  It still has connectivity across all the filaments though.  I think it may have been broken and replaced when the forks got bent and bike parked up many years ago.

Edit.  The unit is actually blown.  Turns out the false readings were due to a short within the connector itself.

 

 

Left bar switch.  Looks to be in pretty fair condition.  Missing the indicator toggle though.  I will take it apart and give it a good clean and regrease during the build.

 

Right bar switch.  Again in pretty good to excellent condition.  That switch is probably the rarest thing on the bike.  It was fitted to this particular US model DT100 only, and only for 1977.  No other bikes ever used it. Reckon that switch alone if cleaned up and working smoothly is worth £200.

 

 

Left side.  Forks are obviously bent in this pic.  New bare tubes are available in indonesia, but I do not think the bike is worth it.  The seal wiping area is in good condition, so I will take them to work and straighten them on the press.  The rust should come off easily.  I ceratainly won't be spending £400 on them hard chroming like the DT175.  Bike just is not desireable enough.

 

 

All in all, she is in quite good original condition for a 46 year old.  The missus seems quite keen to learn how to ride it in the fields behind the house.  It is small enough not to be intimidating.

 

New battery fitted but no power.  Seat base is in really great shape.

 

Edited August 13, 2023 by Tinkicker

[Tinkicker]

The missus being at work, I had an hour or two to do a bit more on the bike.

First thing I did was pull the sealed beam unit. 
Since I decided to fit a UK standard reflector and bulb (exactly the same as my DT175MX unit), I thought I would box the sealed beam unit and keep it safe for someone who needed one as it looked pretty new.  I gather they are getting quite rare. 
Even still had a little green dot paper sticker on the glass like a quality control sticker.
Alas a quick resistance test across the bare terminals revealed that both filaments were actually blown.  It was the connector itself giving a false reading.

Squinting through the glass confirmed it.  Damn.  I was sure it was a good one.

Three hours later and we are down to a bare rolling chassis with a far better understanding of what state the bike is actually in.

And it has its problems, but overall I am pretty happy with it.  I have no inclination to make this a concours factory fresh bike and it suits this purpose well.

So tank removed and about to start pulling off all the electrical bits first.  It is readily apparent that someone has been "into" the loom.  Further investigation required.

First real horror.  Original air filter by the look and with a broken cage.  Luckily I seem to remember genuine Yamaha RT100 filters identical to this came with a new cage.

The thing I am noticing is that very few of the fittings have lost their plating and gone rusty.  A quick rub to get the thin film of dust / mud off and the plating is certainly good enough to refit.  The patina in this condition adds to the bike, not detracts from it. This is almost unheard of on a unmolested 46 year old UK bike.

Again, condition is surprisingly good.  I have had two year old bikes used daily through the UK winter, with our salt ridden roads in worse condition.

Horn, once again in impressive condition.  I tried it across the battery to see if it worked.  It did not.  Boo.  What a swizz.  
It was clear the points had fused together inside, just a click as the solenoid traveled back.  I screwed the tone screw right in, gave it a good clattering on the bench, then took the tone screw right out and gave it a good clattering again in the hope that I broke the bond between the contacts.  Screwed the tone screw in about halfway and tried.  Nothing.  The screw was preventing the solenoid pulling back the diaphragm.
Screwed it out a full turn and PEEEP.  We have a working horn. Yaay!  It would have been disappointing to have had to fit a new one with no patina.

Around three hours later we have a bare rolling chassis and a good idea as to what it needs.  Not much apparently.  Of course the general safety stuff I have on order already, cables, wheelbearings, brake shoes ect.  Then we have the oil pump to rebuild, the exhaust to burn out, the chassis to bead blast and repaint.  I measured the frame and it will fit in the blast cabinet at work with ease, so no need for daft stuff like having to blast it with door ajar.  The door will close easily and the cabinet will seal and develop negative pressure inside.  I can breathe easy with no need for a mask.

Lid lifted off and we are on standard bore size.  

And a quick run around with scotchbrite to clear the carbon ring away round the top of the bore to assess condition.  Bore is in excellent condition with absolutely no wear ridge at the top, the original hone pattern is still faintly visible, and the few scores it has cannot be felt with a fingernail.  A minute or two with an expanding hone will see those gone and a good hone pattern restored.  I intend to strip it of its hardware, take it to work, give it a beadblast to ready it for paint, hone and a good clean out.  I will not even bother to put my bore gauge down it.  New rings and gaskets later and Robert is your father's brother. A nice fresh top end.

 

Edited August 13, 2023 by Tinkicker

[GojuRyu5]

On 12/08/2023 at 18:20, Tinkicker said:

Horn, once again in impressive condition.  I tried it across the battery to see if it worked.  It did not.  Boo.  What a swizz.  
It was clear the points had fused together inside, just a click as the solenoid traveled back.  I screwed the tone screw right in, gave it a good clattering on the bench, then took the tone screw right out and gave it a good clattering again in the hope that I broke the bond between the contacts.  Screwed the tone screw in about halfway and tried.  Nothing.  The screw was preventing the solenoid pulling back the diaphragm.
Screwed it out a full turn and PEEEP.  We have a working horn. Yaay!  It would have been disappointing to have had to fit a new one with no patina.

This forum is definitely a learning experience. I was wondering how to test and ‘fix’ a horn on my ‘Rusty’ restoration. Thanks for the share.

[Tinkicker]

A bit more time spent pulling it all apart, ready for taking the frame and various bits to work for blasting and readying for paint.

Pulled rear wheel.

It was obviously used by kids back in the USA and parked up when it finally refused to start.

 

The rear sprocket carrier nut was loose and had obviously been for a very very long time.  Probably to save carrying a large spanner and time spent adjusting the chain on the trail.  Not good relying on the chain pullers only to hold the wheel back though.  Typical kids lazyness.

 

I took a good look at the muddy brake shoes.  Man this thing has had no maintenance at all.  Drums filled with dried up slurry.

I had a poke at the lining bonding line on the brake shoes, and as suspected, the linings delaminated with very little pressure.  This is why you should never trust over 10 year old brake shoes.  Delamination is very common.

 

The linings readily delaminated with very little encouragement.  Never trust old brake linings.  Genuine Yamaha ones are only around £16 per set, it is not worth gambling your life on.  It is still wearing its original 46 year old IRC tyres.  Do you think I should change them? 

 

 

Judging by the state of that chain pull, that axle locking nut has been loose for years.

 

Front end apart and as suspected, the poor steering head bearings have never seen fresh grease.  They were completely shot. They had been hugely overtightened to take the slop out and the silver flecks are actually flakes of metal, spalling away from the tortured bearings.

I will fit taper bearings for this build as I have no intention of keeping it 100% factory original like my 175.

 

 

So time to start taking parts to work for more attention in my breaktimes.  I work for a very accomodating company who really values their workforce.  So as long as you do not take the piss, they have no problem in employees using works equipment for home projects at break and lunchtimes.

 

So we have the frame blasted and ready for paint.  The access to the heavy industrial cleaning machinery I have at work makes doing high quality restos a doddle.

 

 

I checked the forks yokes for true since the forks were bent and they were fine.  I gave them a blasting also, then into the spray booth for paint.

After allowing the enamel to cure overnight, I fitted the taper bearing cups into the headstock and the cones onto the steering stem.

So much easier using the correct size mandrels and specialised bearing heaters at work than having to use my motley collection of old cast off tools I have at home.

 

Frame and steering stem finished and going home for assembly.

 

 

 

Edited August 25, 2023 by Tinkicker

[GojuRyu5]

57 minutes ago, Tinkicker said:

After allowing the eamel to cure overnight, I fitted the taper bearing cups into the headstock and the cones onto the steering stem.

That frame and the yokes are looking in mint condition there matey. I’m just working on my yolks at the moment, using hammerite instead - I work in Insurance and they don’t have sandblasting and spraying equipment handy (perhaps they should branch out ).

 

You mentioned changing the bearings to taper bearings. How do you go about doing that? Is there room to do that and how did you go about sourcing the parts. I was planning on reusing my original parts with loads of grease as they looked Ok, but this might be an alternative option. Any advice? Thanks and keep up the good work!

Edited August 25, 2023 by GojuRyu5

[Tinkicker]

You just buy the correct set and replace them.  The top race usually sticks out a few mm but is able to be accomodated ok on assembly.

 

Edited August 25, 2023 by Tinkicker

[GojuRyu5]

Mate, thanks for that. I’ll take some measurements and see how it goes. Much appreciated.

[Tinkicker]

An hour spent and we have the steering assembly together.  All the fittings are the original 46 year old ones, with the exception of the handlebar clamp bolts.

They were too rusty to clean up.

Again, testament to being put away at the back of a dry US garage for many years.  Odd to think that the kid who presumably owned it will probably be in his 60s now.

 

 

 

Astounding condition.  I can't quite get over it.  You just don't see that in the damp UK.  My UK DT175 cost many hundreds of pounds in genuine Yamaha bolts, screws and small fittings.  Not this one though.  Most of them are in useable condition.

 

Edited August 26, 2023 by Tinkicker

[Tinkicker]

The missus was out at work so I thought I would strike while the iron is hot.  Being a good boy, I washed up the breakfast plates and cups and put them away.

Then I filled the sink up with a strong solution of Tescos finest washing up liquid and with suds piled high, dropped an armful of bike parts in there.

First in was the oil tank.  A good scrub inside and out, then followed by the main loom and other electrical bibs n bobs getting a good scrubbing.

Then brackets ect that just needed cleaning before rubbing with scotchbrite and painting.

 

To say the kitchen was a right old mess was an understatement.  Remembering the earbashing I got from my mother in my late teens when caught boiling my chain in a tub of Linklyfe chain grease on the kitchen cooker hob, I thought I had better put the parts to dry and clean up the kitchen before the missus returned.

 

It was sunny out, so I took myself out to the back garden picnic table, armed with main loom and multimeter where I proceeded to check all wires for good continuity.  Everything was OK.

The other electrical items were tested also and found to be good.

 

I needed the frame off the floor to save my poor aching back and what I found was a tall, unstable and flexing plastic trolley that I use for my watchmaking endeavours.  Completely unsuitable and prone to disaster.  Perfect.

The prospect of the frame falling off, damaging very rare components, chipping the paint and cracking the conservatory floor tiles should keep me on my toes nicely.

 

Onwards and upwards...

 

First on was the rear inner fender, followed by the main loom and oil tank, everything routed as per the old testament book of Yamaha and then the rectifier and ignition coil.

 

Coming along.  The frame is front heavy, so the rear shocks are nothing more than dumb weights at the moment.

 

 

The speedo glass was foggy with tiny scratches, so it was polished with polywatch acrylic watch crystal restorer for a few minutes and the difference was amazing.  Really brightened it up.

 

 

Dashboard painted,  speedo fitted with all new bulbs and glass polished.  Waiting for a 6v BA7s bulb to arrive for the oil light.  Oddly Yamaha did not supply the bulb separately, you were expected to buy the entire oil light fitting and harness.. £30 juxt for a blown bulb!  The old, blown bulb was a pig to get out, as it was tiny and buried deep, but spurred on by the prospect of paying £30 plus shipping from the Netherlands for a new fitting was quite the motivator.  £8.50 for a box of 10 genuine Lucas bulbs was a big saving.

 

 

I keep banging on about it, but I just cannot get over the condition of the plated fittings on the bike.  Those adjusting nuts and linkeage on the brake light switch are 46 years old!

 

Edited August 31, 2023 by Tinkicker

[Ian Frog]

But did you get the kitchen tidied before your wife got back? 

Cheers Ian 

[Tinkicker]

I did.  She frowned a little in the direction of the sink when she came in but nothing was said.  Must have missed a grain of sand in there or maybe she caught a faint whiff of 1970s two stroke oil coming from the plughole.  Or maybe it was my eyes that kept glancing guiltily over in that direction.

 

Did she know and has stored it away to bring up at a more opportune time or did I get away with it?

Edited August 31, 2023 by Tinkicker

[Ronnie]

3 hours ago, Tinkicker said:

 

Did she know and has stored it away to bring up at a more opportune time or did I get away with it?

 

Of course she knows !   And did you get away with it ?   Time will tell, best of luck !

[Tinkicker]

Yes the only warning I will get is when cupboard doors start slammng in the kitchen...

 

So battery fitted and wiring connected to various switches and bits n bobs.  I started doing my voltage checks before continuing.

 

Red lead to ignition switch is battery +

Brown lead from switch is switched live.

So at the loom side of the switch plug I commenced testing.

Battery live 6.4 volts.

Ignition switch on.  Switched live 6.4 volts. Peachy.

Ignition switch off.  Switched live 6.4 volts.  What?  Why?  Its a new switch.

Unplugged new ignition switch and checked switched live.  6.4v.  Aaargh its not the switch, it is getting a feed somewhere else.

Unplugged red lead from rectifier.  Switched live 6.4v.

Unplugged flasher can 3 way plug.  Switched live just background milivolts.  Aha, its getting through from the flasher circuit.  Which lead?

Tested all 3 leads.  All were at background noise only.  What!

Plugged flasher can back in and tested switched live.  I recalled in horror..6.4v.  What, how?

Unplugged flasher can.  Background volts.  Tested can leads.  Background volts.  Plugged can back in again. 6.4v.  Aaargh!

 

So the brown wire supplies the can with battery voltage and the can is powering up the brown wire circuit without getting supplied with power from the brown or anywhere else? Catch 22.

I needed to lie down with a cold flannel on my forehead.

 

Once I stopped sobbing, I pulled out the Yamaha workshop manual and had a look for flasher can testing.  Nothing, basically said if problems occur replace with a new genuine Yamaha part.  Not helpful.

 

I was looking through the specifications tables and a throway nugget of info came to light.  Apparently the can is a "condenser type relay".

A thought slowly slide across my mind from the right hand side, stopped dead center and started flashing.

 

Condenser = capacitor.  I wonder.

 

Back downstairs, grounded the flasher pins together in case there were charged up capacitors in there and checked the brown circuit.  Milivolts - just background noise.

Checked brown circuit with ignition switch on.  6.4v.

Checked again with switch off. 6.4v.

Disconnected battery.  Brown circuit still at 6.4v.  The flasher can has capacitors that are charged uo by the switched live with ignition on.  Without anything connected to the loom, there is nothing to discharge them.

 

I jury rigged the green neutral light to come on with the ignition.  Switched ignition off again and checked brown circuit.  Background noise..

The lamp was immediately discharging the capacitors as soon as the ignition was switched off.

If I had fitted everything before testing, this would not have happened.

 

Phew.  I thought I was dealing with a Christine type vehicle that would fire itself up and ride around the garden at midnight.

 

It was certainly a new one to me.

 

 

 

Edited September 1, 2023 by Tinkicker

[GojuRyu5]

@Tinkicker thanks for this, I loved reading the process you went through. I don’t know anything about vehicle electrics, and refitting the loom is looming large in the approaching schedule. As soon as I get the frame finished on mine, which is pretty much the next big task, I should be in a position to start the rebuild as all other parts have now been finished (or are at the re-chrome / welder). I was pondering at what point to attach the loom and constituent electrical parts and how I will verify that it’s all working. Your test process and description have helped a lot; thanks.  

[Tinkicker]

Took the fork legs into work and stripped them down at morning break, even managing to get the bits cleaned.

 

That left me with a full 30 minutes at lunchtime to clock them up and get them on the press.

 

Original bend was around 1/4" and I got the runout down to 0.020" on one and 0 .013 on the other before I started chasing the high spot around.  I was out of time, so they will have to do. 

Most bikes that ever went down a bumpy track regularly will probably have 20 thou runout.  It will not be noticeable when the forks are in the bike and the runout is up by the yokes, so no matter. 

It was hard to spot at 1/4" unless you were looking for it.

 

 Fork lowers were dumped in the paint stripping tank to get the original paint off, before the alloy was polished and then scuffed to a satin finish.  They were finished off with four coats of clearcoat each.

 

So rebuild time.  This morning I fitted the oil locks to the damper rods, dropped them down the fork lowers,  dropped in the springs and upper fork metals, followed by the inner fork tubes.

Whistling a happy tune I excitedly tore open the fork seal and dust seal kit I had waiting and dropped the seal onto the tube.

 

It fell down the tube..

 

What the...  A look at the seal confirmed it.  The seal was 30mm.  The fork tubes are 27mm. Dammit.

[Tinkicker]

Progress has been slow this week, mainly due to the parts situation.

I envy the US with its huge motorcycle market and consequently a very good supply of restorable bikes and spare parts at reasonable prices (apart from the NOS price scalpers).
In the UK, we never had such a huge market and consequently relatively small stocks of bikes and parts.  This makes  parts almost impossible to find at times, esp on a fairly unpopular bike. 
I bet in 1977, Yamaha UK or  Mitsui machinery sales as it was known then did not sell 50 DT100s.
Add in a US only spec bike and only that spec in 1977 and you get the picture...

Consequently one has to get creative.

The throttle cable was broken in two at the handlebar adjuster, just the inner holding together, so I needed a new throttle cable upper.  The connecting cylinder was also broken.  I found a NoS cylinder in a couple of days of searching and ordered it.
The cable was more problematic.  No trace in the UK and Europe.

I did find one in the US for $150.  Jog on mate, not a chance you charlatan.
I found another in Aussie land for $40 US and  $75 shipping.  Ouch.

Time for aftermarket.  Ebay motorcycle parts sellers seem to think that one DT throttle cable fits all. Useless.  Even the thread pitches were different to my bike, they being course metric and my bike being fine metric.

I could not even strip it for parts as its construction was entirely different.  I was going to have to use my original oil and throttle cables and the new cylinder.

Time to look at other DT100s to see if anything was available that looked even close.  Later models had the same cable as mine, so that was out.  That just left the earlier models.

Closest to original seemed to be the 1976 and I found a NoS one one fleabay.  At £30 it was an expensive gamble.  I already knew the guide elbow was at a different angle, but I was confident it would fit. 

Cable arrived and before fitting it to the throttle tube, fitted the lower cables  into the cylinder and clipped them into the upper cable piston.  Time to clip it together and fit it to the throttle tube.

Piston would not go into the cylinder.  It was about 2mm too big as was the cylinder cap. 

 .
Also the inner cable was about an inch longer.

Who would have thought it?  Dammandblastit.  Time to get creative. 
Had a good look at the parts and decided the only way was to cut the inner cable to the correct length, fit my old piston and cap, then solder on another nipple.

Not having a nipple, I had some lucar terminals that had a copper tube core inside the crimp section, so I had a new makeshift nipple.  Cut the required section from the terminal, tinned the inner cable, cut it to length, fitted my old parts and crimped, then soldered on my new nipple.

Fitted it to the carb and the twistgrip.  A quick adjustment and we have closed throttle with healthy free play one way and fully open the other.
Yippee.  I can wipe the sweat from my brow now.
Handlebar switch and cable fitted back on bike.

Looks like it was made for the job.

Even got the bend angle sorted without kinking the tube.  Another bullet dodged.  It could have all gone horfibly wrong and often does.  I got lucky.

 

Swingarm and chain guard fitted.  Just noticed those chainguard screws in the pic.  Looks like they need shortening.  I am wondering how easy those shocks will come apart.  I want to blast the springs and repaint.

Edited September 3, 2023 by Tinkicker

[Tinkicker]

And we come to that point in the resto where it takes its first breath...

 

Very pleasing.  Nothing worked when it arrived.

 

 

[Tinkicker]

Front end is back together as well as the rear end.  I have quite a few parts finished that cannot be fitted until I get the rear wheel assembly sorted.

For that, I need as a minimum, new brake shoes, new sprocket carrier collar, new rear sprocket, lock tabs, new chain pulls, and one I will replace as a matter of course - the sprocket carrier bearing.

The missus has taken to keeping the debit card in her purse out of my way until next pay day.... "Its not a race to finish it", says she.  So back to my tiny man cave muttering and grumbling under my breath.

 

Front wheel was attended to.  Given a good scrub and polish, the hub given a few coats of satin tough black and the wheeobearings removed, cleaned, inspected and re lubed.  Normally I fit new bearings as a matter of course, but because the budget is so tight on this bike, the £12 or so replacement cost can be spent elsewhere.  It would have been a waste of resources to scrap perfectly good bearings in this instance.

I have to try keep the restoration costs and the post restoration value somewhere close to each other.  No point spending £5k on a bike valued at £2.5k.

The 175 being a very desireable, museum quality bike is professionally valued at £7k.  I bet I have close to that amount invested in it. 

The 100 will never be as desireable, hence the budget.  Saving grace for the 100 is what good condition the original fittings and bolts are in.  It is very easy to get carried away with restorations and although they are a long term investment, you do not want to be in a position where you have lost £1000s.

 

The chrome on the rim is excellent.  No pitting at all, as are the spokes and nipples.  Still got their plating.

Then we look to the brake backplate. It soon became obvious tht the bike had been parked up after riding through a deep stream.  Muddy water left in the speedo drive chamber had dried out over the intervening 40 odd years it sat.  The drive was seized solid.

It took hours upon hours of coaxing and heat to get it moving and stripped down. Thankfully it is working now.

 

It cost around £200 to get my 175 front wheel in a similar condition.  Total cost for the 100 is around £2 for paint and materials, plus  £15 for  brake shoes and springs and about five hours or so of my time.  The only new item externally is the brake check decal on the backplate which I had left over from the 175 resto.  Everything else was fitted on the Yamaha production line, 46 years ago.

 

The front fender was very sun faded, so I tried the trick I saw on youtube to restore the colour.  I thought it was complete BS, but thought I would give it a try... Heat gun out and gave it a good going over.  By gawd, it worked.  It actually worked.
Pity I cannot shift the black staining.  Nothing will touch it.

Front end sporting its now straight and rebuilt forks.  I think the axle casttellated nut is the wrong one.  It is too narrow to reach the cotter pin hole.  The 175 nut is much deeper. Stuff like that drives me insane.

My tiny man cave is eminently suitable for repairing watches, but entirely unsuitable for storing and rebuilding motorcycles.  The number of times I have grazed my back on the handlebars of the 175 just out of shot when standing back up...  It will be a long time before it is suitable for watches again.  Place is filthy.

A few cables, a new tyre, and a new headlamp reflector and bulb and I can pretty much call the front end finished.

Rear end back together.  All the small parts, chain guide, brake torque arm, rear brake pedal ect are all ready to fit but need the rear wheel in first. When enquiring about the prospect of purchasing the required parts to complete the rear wheel, the missus snapped her purse closed so fast, it nearly took my finger ends off.
The rear shocks responded remarkably well to treatment, very pleased with them.

 

Edited September 17, 2023 by Tinkicker

[GojuRyu5]

Looking really good @Tinkicker. The paint job is awesome. Great progress!!

 

I certainly understand the finger risk of such projects . Similar conversations in many homes up and down the country, I’m sure

[Tinkicker]

Time for a little research.


New front brake cable arrived this afternoon.  The old one has a damaged outer sheath and rust has penetrated into the cable through the coils.  It works, but looks crap and feels worse.
I can never deem a rust penetrated brake cable fit for the road.  Just have no idea whats going on inside and it will probably bind like buggery under tension.

Time for a replacement.  Hmm seems like they were made of unobtanium with a half life of 10 years.  Someone is trying to sell a used one on ebay for £45. 

 .   Jog on.

Enter the aftermarket sector.  DT100 front brake cable fits DT100 1974 to 1983......  Permit me to be a sceptic.
Still, no choice.  One duly ordered and arrived.

Offered it up to the bike.... 

1. The thread for the original, separate lower adjuster in the back plate is 6mm.  Thread on new pre fitted cable adjuster is M8.
2. The bottom nipple on original is a 8x10 barrel.  The new cable sports a pear nipple and no split barrel supplied.
Neither of the above are insurmountable, although deeply undesirable.
Kindle out with official Yamaha book of words.  Page on cable routing.
3. Cable is about 4" too short.  It won't even reach the backplate adjuster lug.

Cable back in its packet and once again I have to send a piece of aftermarket garbage back to its garbage seller.

Measured up the cable, put in a search of cable length (1100mm) and yamaha brake cable.  A website for a bike shop in Thailand offered the info that it had for sale a RXS100 brake cable, the length of which is 1100mm. The pic looked identical to the DT cable, right down to the rubber sheath on the end.

A look on CMSL gleaned that the RXS100 uses the same separate 6mm threaded lower cable adjuster as the DT.  So it looks like we are in business.

A search on fleabay found a new aftermarket RXS100 cable at less than a tenner and the pic looked encouraging, it looked to be the same as the Thai cable, so I have taken the gamble.

Will it be another facepalm moment?  These large aftermarket bike spares warehouses seem to think if a cable fits a 1978 DT400, it will also fit the rest of the DT models, all years and all capacities.  Must cost a fortune in returns. 

[Tinkicker]

Exhaust decoked, prepped and ready for a coat or five of high temp paint...  Very happy with the condition of the downpipe.