This thread is off the back of the Air Cooled Two Stroke Paranoia thread so as not to ambush that one. 
Many have shown a lot of interest and enjoyment in that thread, so I thought I would resurrect one I did on another forum, detailing the trials and anguish of putting this particular bike right for your amusement at my misfortune.

The reader may then understand why a once professional motorcycle techie at the top of his game is doubting himself and showing signs of paranoia.

It is not pretty reading and the horror extends far further than the average bike.  It was discovered by a complete imbecile who destroyed everything he touched in the name of restoring it.  I almost took him to court over it. 

It will be a long thread and take a long while to finish.  Probably months.

Are we all sitting comfortably?  Then I shall begin.

Background.

A  DT175mx appeared on fleabay that had been fully overhauled and restored by a motor industry professional.  A college motor vehicle tutor no less.
It looked very tidy from the pics, albeit with one or two things that I could see were not correct.  It was being sold to make way for another car project and was priced below the average restored example because it had a 12v conversion but had some minor problems with the electrics that he could not get to the bottom of.

Since I intended to make the bike all original again, including the electrical system, it would not be a problem.  It came with a full written history and provenance of why and how it was found.

Bare Bones of the Letter of Provenance

So 1979 we have a British Ex Pat living in Hong Kong who met an English woman, they got married, settled down in Watford and had a kid. 
To get to work, he bought a brand new Yamaha DT175MX in the summer and it is known that the guy disappeared after the bike was involved in a road traffic accident around six months later.
I was told that he probably ran away to Hong Kong again, but the circumstances are glossed over.  Given the curse on this bike I think it is possible he was killed in the accident, but as far as I know, he just abandoned his wife and baby and absconded, leaving the lightly damaged, six month old bike with less than 2000 miles on it behind in a shed.
It stayed there untouched under a sheet for 40 years.
The college lecturer was a keen car restorer and was looking for another project to keep him occupied in his newly retired state.
He came across one of his old students and after a chat over coffee, the student said his mum was moving house and wanted rid of his dads old bike.  He could have it if he wanted.
He obtained it and "restored it".

After 40 years all the paperwork had gone missing and it is thought the number plate was torn away in the accident, or otherwise "upcycled", so there was no registration number and no log book. 
Luckily the matching frame and engine numbers were fully intact.
DVLA were contacted about the registration number, but because the registration was inactive for so long, no tax or MOT history, there was no longer any record of it.  However the permanent DVLA stolen vehicle database confirmed that the frame number was not on the stolen vehicle register.

The Vintage Japanese Motorcycle club was contacted with pics of the bike in its pre-restored state and the frame and engine numbers.  They looked through their official Yamaha records and confirmed that the bike was assembled at the Yamaha Iwata plant in Japan during mid August 1978 as number 348 in the production run and was intended to arrive in the UK for the 1979 model year.
From the pics it was confirmed that the paintwork, decals, colour and UK specific parts were all in keeping with a 1979, UK spec, DT175MX.

It was given an age related registration number by DVLA, restored and a complete clown who ignored his own rules, bought the bike on the strength of the pics and faith in the restorer as a motor industry professional.

The clown thought that for once, he would not have to get his hands dirty.

What a fool.
 

Ok, you have my attention.....but..... can we have a pic or two to go with the background ?
Looking at another th'd it has come to my attention pic's are not loadable at this time. Post when you can.

Trust me. There will be pics aplenty.

So the bike arrived one sunny Saturday morning and was taken round to my lair. It still looked the biz, but it was noted that the right hand mirror was loose and spinning.
It appeared that it had been glued in with JB Weld or something.
Looked at the remaining wreckage of the threads in the brake perch and they looked like they had been drilled out.
Looked at the el cheapo, non standard mirror and noted it was a right handed thread.

I knew for a fact from when I had a brand new DT175mx in my youth that the mirror boss had a left handed thread. It caused great consternation back in the day when I first tried to adjust it.
So front brake perch added to my to do list, along with reproduction mirrors.

I noted that he had fitted cheap, non standard, tiny LED indicators in the ad and I had ordered repro ones before the bike was delivered, so it was time to swap those over.
Pulled the headlamp unit out to get at the wiring and noted a lot of crimped on lucar terminals in the headlamp bucket and gaffer tape on the rear of the reflector.
OK, I will pretend I did not see that at this moment in time. I knew it had a couple of very minor electrical issues in connection with the 12v conversion that I would be sorting when I put it all back to standard 6v as Yamaha designed it.

Key on, indicators flashed very quickly but the repeater light on the revcounter did not. One of the issues mentioned in his ad.

Horn did not work as per ad and instrument lights did not work as per ad. Very odd combination of faults that it turned out was probably in connection with the accident damage in a very strange way.

Road test time.

Started it up and took it on a route around the village that kept me close to home as I did not yet trust it. It sounded and performed very flat from what I remembered.
A few hundred metres down the road it cut out. What the dickens...
Coasted to the side and discovered another foible that was not mentioned in the ad...

It would not change down the box. Finally managed to get it in neutral after a lot of rocking and manipulating the lever by hand.
Now why has it cut out?
Spied the fuel tap in normal position, was it needed on reserve?

Note that I have not had a bike with an accessable fuel tap and a reserve position for many years, so when it died, I had not immediately reached down to flip it to reserve, something that was once an instinctive action.
This saved me from a long push home.  If I had, I would not have noticed the problem with the gears and carried on.

Tap on reserve position and it fired up. Rode it back home in second gear the 300 metres or so and it cut again, just as I was pulling in the driveway.
Turned out the tank was bone dry (reason noted later in thread) and the old skinflint must have drained the fuel out, leaving just enough in to start it.

As for the gearbox, again was not too concerned. Had come across that before and knew it was either the stopper screw out of adjustment or the shift lever spring was weak or had broken. A very cheap fix.

How very wrong I was as it turned out.

But why had he failed to rectify it when he rebuilt the motor?

My faith in the seller as a motor industry professional and avid classic car restorer who knew what he was doing was slipping.

How much did you pay for the bike, and did you carefully check it over, and have a test ride before purchase?

Ordered a new shift spring and while waiting for that arrival,  resolved to pull the tank and seat, then take the lid off the cylinder of the "fully rebuilt engine" to see what was going on in there.  It did not seem to have much compression, you could work the kickstart fairly easily by hand and I figured he might have broken a ring, hence the flat engine power.

Pulled the tank and what confronted me was a rear damper in name only. It was bolloxxed.  Certainly in no way in a roadworthy or even serviceable condition.  Oh MY GOD.  What have I done?

It hit me that the seller may well be a motor vehicle  lecturer, but he was a complete buffoon.  God help anyone riding in those cars he "restores".

A phone call to the suspension specialists who hard chromed the fork legs of my VFR750 ensued.  Enquiries were made about rebuilding the shock.   Nope, not intended to be rebuilt, but anything is possible.  Is the chrome on the damper rod good?  Nope, badly corroded.  Loud hissing of air being sucked through teeth came doewn the line. Forget it, it was going to cost a bundle, better to find a good secondhand one.

A few days later I came across one on a bike breakers website who specialised in importing bikes from road salt free california and bought that.  It was to be from a sub 5000 mile bike and was almost like new.  ££££££s later and it was on the way.
Fingers crossed that would be the only big issue I find, but of course, deep down I knew I was in trouble. 
I am not a guy known to be lucky and always have to work harder than the next guy for the same result.  It is the theme of my life.

Looks nice doesn't it?  It certainly fooled me.
Proper indicators fitted, but progress is going backwards.  Look how he fitted the rear brake rod and cam lever.  


And this was deemed fit for a fully overhauled bike by a motor industry professional.  Corroded damper rod and damping oil spraying everywhere.



 

Your shock can be rebuilt, but will need a new damper rod making. Finding a good used one is likely to be difficult/impossible, as the bump stop rubbers disintegrate over time. Try contacting someone who manufactures shocks, rather than chromes fork legs.

Lid off the cylinder and it is obvious that the bike was indeed a sub 2000 miler and that it was left undisturbed for 40 years as described. Absolutlely no wear ridge in the bore, but there were a couple horizontal bands of deep rust pitting where the piston rings stopped all those years ago.
I was surprised the restorer deemed a rust pitted cylinder to be serviceable and not have had it rebored. At least I knew why it had soft compression now. He probably cleaned up the rusty rings and refitted them.

Looking at the pits, I judged it was touch and go whether 1st oversize would clear them out, so bit the bullet and ordered a decent quality second oversize piston.

Then it was time to pull the barrel. More excitement. The alloy hold down nuts were badly corroded and a hex socket would not grip one of them. Looked like a dog chewed on it.
If he had " rebuilt" the engine as he said, why did he not replace these nuts?

Got one nut off, measured how far up the nut, the internal stud went and drilled a hole in the nut just above where the top of the stud would be.
I then used a crosshead screwdriver as a tommy bar to loosen the nut.

As expected, the piston and rings were original and had seen better days.


Deep pitting in bands around the cylinder. Shame, no wear evident. At least it supported the provenance claims evidentially.

Had a look at the little end eye in the rod  Looked to have escaped major corrosion, but did have a small black water mark.  I figured that a new small end bearing and piston pin should do the trick, it is not as if this bike was going to be doing major mileage.  I just gave it a quick rub with 800 grit to erase it and pretended I did not see it.
At work, water marked bearings are cause for rejection, but then my stuff is required to perform without fail for tens of thousands of hours in large wheel loaders ect.  

Looked over the big end bearing and it looked OK, no radial play apparent and nothing special about the side play and after all, it was a low mileage bike.

However, when I spun the crank, the mains were grumbling and growling like a pack of hungry dogs.  The tracks were obviously corroded, yet they had been deemed to be serviceable by the previous "restorer".  Seems that the oil capture channels in the cases had guided condensation down into the bearings and rusted them out.

 I was going to have to split the cases too.  Just great.

His ad said that all cables were new.  Does that oil cable look new to you?


Present thoughts.
This bike is truly cursed.
I have a feeling that the decision not to replace the rod and big end at the time is about to come back and bite me. Not because of bearing play, but because I have a nasty feeling developing that the crank is actually misaligned due to brute force and ignorance by the PO and I never bothered to check.
Strange thing is it spins freely and everything I know said it was OK. Yet there is a vibration through the pegs above 5000 rpm and I am starting to doubt myself.  I have professionally rebuilt literally dozens upon dozens of two stroke motorcycle motors over my career and this one is just not playing ball.  I think I am losing my mind.





 

The bike isnt cursed. Its just something that has been standing for years, has had a couple of £100 spent on it, so it looks good cosmetically, then advertised for top money, in the hope it will be bought by someone, on the strength of pictures alone.

Thats something which almost always ends badly, and costs a good deal more than properly restoring a tatty but complete runner.