Popped in with an interesting pic from my work bench....

Wonder if the silly old sod has decided to branch out into 300 tonne mobile crane transmissions?


700bhp and no lubrication make for uneasy bedfellows.





 

Oh wow, that hurts to look at. Wouldn't want to be paying the cost of fixing it either.

Yes. Last one I did of that type with similar damage came out at over £50,000 just for the parts.
Big stuff comes with big ticket prices. All that damage due to a cascade pump failure and a driver who did not smell burning or see the smoke billowing out from underneath..

Back to the small stuff...

So I gather up my courage to pull the rotor and stator. Fingers crossed that those coils have not been struck with a hammer or weighed in for scrap.

Stator off and my giddy aunt, what has he done? It looks like he has tried to run everything from one source coil and trigger coil.

Why would he do that, unless the coils are toast?

Multi meter onto the coils directly and we have continuity and what is more, continuity in the right ballpark.

What a bleeding mess. I feel the need once again to stress this bike was six months old when it was stored away. Why did he mess with it?

Trying desperately not to look at the rest of the loom heading for the headlamp bucket.  What is going on in there?


I have been puzzled as to why the generator rotor is rusty on the outside for months.  It suddenly hit me looking at the pics.  Everything points to the bike getting dropped on the left, from the twisted shift assembly to the rear lamp leaning to the right.  There are other things discovered that point to a hard drop on the left hand side too.

In the rotors case, the generator cover is plastic.  I am betting that it was broken in the accident and replaced by the previous restorer.  That would account for moisture getting into a sealed chamber.
Which leads me to another question regarding some problems I am having on another thread.  I had better clock that rotor to see if it is running true.  The crank end could be bent...  . Holy feckeroo.

Anyway. Set to with the new wire I ordered and made up a new stator harness.

Hurray, we have sensible readings on all wires now. Just waiting for the harness to arrive from the US, so I can fit it to the bike, can cut the stator harness wires to length and fit matching terminations.

Grabbing some more corn nut’s and a few brews… waiting for the crank shaft end resolution…
Sneezles61

Every day I have thought to myself that I must bring one of my gauges home from work.
Every day I forgot.
Since these days, I recently started only working 4 days a week and Thursday is my new Friday, it was imperative that I not forget or it would have to wait for Monday.
Of course I forgot and remembered just as I got settled in the car to drive out the car park.... Back to my toolbox,  grabbed the first one to hand and ran out the door.

If there was any motorcycle in the world that was designed to be mag mount resistant, it is the Yamaha DT175MX.  There is not a single, flat steel surface big enough for a mag mount to get a reasonable grip on anywhere near the engine.  Bashplate was my favourite idea, but proved impossible, even with my smallest mount.

In the end I fitted the mount to the bike stand, not ideal because any movement twixt stand and bike would throw off the reading, but hey ho.  I would have to be very carefull.

The crank is straight as far as I can tell, but the rotor is slightly oval shaped the widest point being 90 degrees from the timing mark.  Widest point is 0.030" with 0.015" at 90 degrees before the mark and 0.015" at 90 degrees after.

I had kittens when I first saw it, I thought the crank was running 15 thou out, but I looked a bit more carefully and the readings were plus 15 thou at both points.
At the timing mark and 180 degrees past it, the readings were 0.001" apart.  I can live with that.

 I have no idea what it all means.  Are the rotors usually slightly out of round?  I dunno because I never clocked one up before, and the manual is no help.  It has no specifications on rotor concentricity or runout and it is stamped steel, not a machined forging, so I doubt they are perfectly round.

But I dowwnt knowww.

What does it all mean?  Gauge was reset to zero at the high point and the engine turned backwards in the pic.  Timing mark is about 15 degrees before lining up with the gauge and it is showing -0.015" .  If I continue turning it, it will go to zero, then -0.015" at roughly 180 degrees, then zero again at 270 degrees.  The high spots are top and bottom of the rotor.









​​​

Interesting. I've never tried clocking the flywheel but only the crank when out of the motor while rebuilding.
Be good to know how the crank clocks up without the flywheel if you can get the gauge onto a flat area 'just' past the taper while still in the motor.

Secondhand loom arrived from the US and was duly fitted from the rear forwards.  I need to build up to actually delving into the headlamp bucket in depth because I am very afraid of looking.
I had already noticed a different looking lightswitch on the left bar, it did not look right as it was roughly touched up matt black paint, had a single dip and main switch, indicator switch and horn button.  The shape and the switch toggles just did not scream yamaha to me. 
Furthermore, it felt extremely gritty to operate and was clearly on its last legs.
I guess the original was damaged in the accident and had been replaced by whatever the previous owner could get his hands on cheaply.
I checked in my parts book and the correct UK one had lights on/off, dip/ main, horn and indicators.  Found a repro one on fleabay and ordered that.

But that meant  I had another problem brewing.  I had a US wiring loom and the US left hand switchgear was in fact similar the one I discarded with just the dip and main, indicators and horn.  This meant the correct UK one was not going to be a simple matter of plugging straight in to the US loom.

The bike came with a brand new four position ignition switch to operate the ignition switch and lights.  It had dual multiplugs.  I figured that the switch was wrong because why would you have lighting on/ off controls on both the ignition switch and the left handlebar.

I double checked the parts book again and crossed referenced with the US parts book.  The US had a two position switch with one multiplug, the European variant had a two position switch with one plug.  The UK specific switch was the four position one with dual plugs.  The wiring diagram showed a two position switch...
Both the Europe and the UK had the same left handlebar switches and the US had a different one.

Someone was telling porky pies.  I surmised that the UK specific switch was likely a mistake for the reasons already outlined above.  Either way, with no way of knowing, I elected to go with the two position one.
That decision turned out to be the wrong one in the fullness of time as it denied me the use of a parking light.
But since it will never be left out on the road after dark, I can live with that.

This was not going to be a simple plug and play exerience.  With the differences I already knew of between the US and UK looms with the way the lights worked, the differences in the charging system, then the different left switchgear, this was going to be a major rewiring job.

US loom arrived, I could cut my new stator harness wires to length, fit the correct terminations and plug it into the main loom.


Around the same time, the new CDI arrived from the US.  For some reason, the previous "restorer" had removed the CDI holder, so I made up a new one, fitted the new rubber shock mount and plugged in the CDI.

 

Tried to get hold of a genuine voltage regulator for months but it appeared they were made of unobtainium.  Everything on offer was overpriced, rusty tat.
I ended up buying a 6v  Italjet scooter regulator is it was a small form factor and did not look modern, all fins and huge heat sinks.
Made up a new harness for it so it would plug into the existing loom.

That silly old man has certainly made life difficult. Why is that in the UK, unless you are very lucky, an idiot always finds a complete, untouched bike first and decides to "modify" it?
I can completely understand one getting converted into a kids field bike over the years with the road equipment removed ect, but why would a supposedly rational person come across a 40 year old bike, decide it is worthy of restoration, then proceed to trash it?

New Zener fitted.



In hindsight, with all the rewiring work needed to convert the US spec loom to the UK spec without it looking like a cobbled together bodge, I made the wrong decision.
It would have probably been easier to make a pegboard and make an entirely new main harness from scratch.

As I did not want to cut open the US loom to access and modify the wires that made the tailight "always on" with the ignition, and the two step charging system, I ended up making a piggyback harness to carry the necessary wiring.
Not great and not original, but without destroying the integrity of another rare wiring loom, the best I could do.

The standard I was looking for was that in another 40 years, after I have gone in the oven with the gas turned full on and taken a quick trip up the chimney;  that the next custodian of the bike can look at the UK wiring diagram, look in the headlamp bucket, and see all the wires in the correct colours and with the correct plugs so it is a simple matter to trace a fault.

Not something I found when I removed the headlamp and peered inside..

Oh my giddy aunt.  The guy is a moron.  No wonder he could not rectify the electrical problems he had built in.
When the hole you are digging is down to a level you will find it difficult to exit, you put down the spade.
Even more galling is the original wiring before he got his hands on it was in excellent condition, clean with no corrosion or brittle insulation


I mentally closed my eyes and quickly removed the rest of the old loom.  I did not want to see the finer points of his wiring accumen.  I did not want disturbing dreams to ruin my sleep.

So I turn my attention to the headlight unit.  Nothing to go wrong with that is there?  A simple reflector, bulb and bulb holder.  Nothing to test anyone with an ounce of sensibility.
So what is with all the gaffer tape on the back?

With much trepidation, I pulled off the gaffer tape, exposing an LED headlight bulb, loosely plonked into the back of the reflector.  The gaffer tape was holding it in.  It had no other means of support.
Since I intended to put the headlight back to standard 6v, I already had the requisite 6v 35w amarican pre focus bulb in stock.  But it appears that this latest development means I have no bulb holder to fit the bulb into.

To coin a phrase from the twitter generation OMG!     in place of the original bulb holder, he had wired in a modern three pin H4 connector.
It gets worse.........
To make matters worse, the LED bulb base was bigger than the original parts, so he took a dremel to the reflector to open it up a little....
I am pretty sure if I killed the idiot now, the judge would be sympathetic to my predicament and let me off with a caution.
Every breath the guy takes is stealing oxygen from the rest of the population.

No bulb holder, hole enlarged with a dremel and the wrong bulb plonked loosely into the hole.  What are the chances that it was sitting at the focal point of the reflector?  ZERO.  I would not want to be employing any of his students.

​​​​​Rare, original headlamp unit destroyed on a whim.  I needed to order a new one.  I felt sick..

Tinkicker I admire your tenacity, can be a real drain when it's one problem after another.
As I often say when there's a problem, "it's another opportunity to excel".
I'm not sure I would like as many opportunities as you've had with your DT though 
Hope the rain clears and you get a chance to prove the new coil has sorted the running issues.
Might get mine out later if it dries up.

So we have the US loom fitted as far as the steering stem and was about to rip out the original butchered one. 
It almost broke my heart to see it.  It looked like it was only 12 months old.  It was in excellent, pre idiot condition.




Carried on taking the front end apart.  Front end off floor and of course, I did the standard safety test for the wheel bearings and steering head bearings.  Wheelbearings were fine as they should be, they were supposedly replaced by the previous owner.
More alarming was the fact that the fork legs could be walked about three inches forwards and backwards.  So steering head bearings very loose.
Another potentially dangerous and dangerous category MOT failure.

Dropped the legs out and the top yoke fell out of relationship with the bottom one because the stem pinch bolt and steering stem adjuster locking bolt were finger tight.... Sigh.

Came to remove the front brake perch with the damaged mirror thread and to my not very great surprise, the front brake light switch fell out.  It looks like he broke the lock tab when removing it before and had just wrapped it in electricians tape and stuffed it back in the hole.
These things are readily available and cost a fiver fer christsake.

Front brake light switch held in by insulating tape.


​​​​​​Time to remove the instrumentation.  It said in his ad that the instrument lights and the indicator repeater light had problems.
The instrument lights did not work at all and the indicator repeater only worked on the left indicators.  I subsequently found out that the low oil tank light did not light in neutral either.

However, no problem.  All the lights were connected by multiplug and bullet connectors.  Straight wiring from connectors to bulb holders.  Nothing to go wrong there.
So I had unplugged the connectors and prepared to put the tach to one side for now, then had a brainwave.  I would test for connectivity across the connectors.
On a closer look.  Oh my word, he had " been into" the tach harness.  Holy feckity feck.

Why would he do that?

The wires had been cut, twisted together, wrapped up in insulating tape or the occasional bit of shrink wrap.  I consulted the wiring diagram and found that the wire colours such as sky blue that should go to the bulb for the neutral light, did not in fact go to the neutral light.  He had mixed and matched the wiring colours to his own mad design.



Nothing for it.  I was going to have to repair it properly and restore the original wiring colours.  I had bought some 6v instrument bulbs to replace the 12v items he would have fitted.
Need not have bothered.  He neglected to change over the original 6v bulbs to 12v.

This mans stupidity is boundless.  Not one wire is the correct colour or connection and all have been cut and twisted together in a linemans splice.  Not a splash of solder anywhere.



Luckily I now have a stash of wire in the correct colours from the old loom.  I no longer had to order it in.

Repaired harness, correct colours, connections and repairs soldered and shrink wrapped.