You are right Mark. I let him get under my skin. Adjustments have been made.

Carrying on apace. Waiting for the engine parts to arrive, so turned my attention to the rear end. Some wiring was not routed correctly, and I had noticed that the rear lamp assembly was listing to the right.

Thankfully it was not the rear frame loop that was bent, it was the rear fender stiffening plate. Either got slightly bent in the accident or bent when he had it beadblasted.

Since I have a very long history of unintentionally bending sheet metal in beadblasters at work, I cast my eye over it and formed the opinion that it was accident damage from 1979.
A quick twist here and there soon had it looking much straighter. More worrying was the fact that it was untreated steel. He had not even bothered to paint or clearcoat this rare piece of automotive rocking horse poo.

Four coats of Tough Black sorted it.

The rear light had a definite list going on.


Engine parts arrived, the left case heated up, crank slipped in, new rear mounting damper fitted twixt the cases, transmission dropped into place and tested, then the right hand case dropped on with the merest smear of threebond 1215 in the joints.

Stator and rotor fitted loosely and we turn our attention to the right side.
Shift shaft in, shift selector arm on shaft with new centering spring and new shift arm assembly spring (the likely culprit for the transmission not downshifting).

A quick adjust of the stopper screw to align the centering marks and lock it down.
With a flourish I fitted the gear lever loosely on the splines and it was time to amaze the world with my transmission repairing prowess.
Smugly spinning the input shaft, I deftly selected first, second, third, fourth, fifth and sixth gears.
Sixth to fifth to fourth to.... fourth and fourth again. Dammit, it is not changing down.
More adjustment, same result, and yet more adjustment ignoring the centering marks altogether had a transmission that changed up like a dream and down reluctantly.

Spin the selector drum by hand and they snicked in and out perfectly, with selector arm fitted, they shifted very poorly. The selector arm assembly must be twisted.
More expense to be spent on this "fully overhauled motor".
No way would he have not known it was not changing down.  I think the accident involved the gear lever clouting something hard enough to bend the selector arm assembly.  The list to the back light and other feckwittery I come across later definitely points to a heavy drop on the left hand side.

To say I was miffed would be an understatement. I sloped off, shoulders slumped, cracked open a beer and had a bit of a sulk. A few beers later and I felt better and resolved to order the parts in the morning.
I would wait for the missus to have another drink before I broke the news to her.

Parts ordered, I dropped the motor back in the frame with all new genuine bolts and nuts and loosely assembled the right side hardware to keep any small parts from being robbed by the infamous part robbing pixies during the night.

Bottom end back in the frame. I really wish I had checked that crank for alignment before I rebuilt it. The cases fitted tigether fine, it turns perfectly freely and there is nothing I know to suggest anything is wrong with it; but the paranoia is biting because of a very noticeable vibration through the pegs at 5000rpm.
I am used to 4 stroke V4s plus a long line of other multicylinder bikes and cannot remember if my other DT vibrated like that.

My DT175C has that same extremely noticeable vibration thru the foot pegs at higher RPMs. None of my other 175s have that issue. I haven't started the troubleshooting process yet......

Loose engine mount bolts are a comon source of vibes. That, & left main been spinning on the shaft for long enough to wear the shaft & have up & down clearance by feel on the mag flywheel, but more comon in motors below 125 with the smaller left side main. [have that issue on my LS3--just gotta get enthused to fix it].

Great. Some constructive contributors.

I never wanted this thread to be a story about one idiot's journey to completing a horror of a bike.
If you have your own pertinent tales, constructive advice or anecdotes of woe in relation to the post at hand, please share them so we can all learn something new.

The original thread i spoke of ran to over 100 pages with dozens of contributors.

This was never intended to be a one man show.

Carried on with bits n pieces. Some may have seen me mention Simonize Tough Black paint on various threads recently. Available as gloss or satin fnish.

I painted the clutch and oil pump covers with tough black satin, indeed I also use it on the cylinder and head. It is able to stand up to the heat very well and is chip resistant.
It matches the original paint very closely, esp after a rub with a silicone lube soaked rag.

Clutch cover.

My post was cut in half for some reason, maybe something with the pics.  Never mind, managed to recover the lost part.

After months of finding and looking through parts books, I finally found a brake rod that looked to have the same ends as my original and the proportions looked right.
It was not expensive and I thought it might fit after modification.  It had a bend in it where my original did not and maybe I just needed to straighten it.
It actually came off a 2020 Asian market DT125 or 175 if I remember correctly.

I need not have worried, it fitted like a glove, even the bend was in the correct place to clear the swingarm.

Plastic bag is the correct part number if anyone needs one.  It can be ordered from Fowlers in Bristol, if in the UK.


Turned my attention to the fully overhauled carb. 
Carb is a Mikuni VM24-005 iirc and according to the advertisement, was fitted with a new main jet.  
Unfortunately that main jet was wrong.  It was a #120 and the UK spec for the 1979 DT175mx is 130 or 140 main according to Yamahas good book.

I split the difference and went for #135.

Sods law and my terrible luck came into play and in hindsight, it would have been better with the #130.  
Plug insulator at high throttle settings is a milk chocolate brown, although the incredibly poorly machined rebore might have had something to do with that.  
Oh yes, my good fortune has no end. 
I suspect most already know about that particular sorry tale of woe.

​Anyway I fitted the 135 jet, gave the non teflon tipped float valve and seat a quick lap in with metal polish and set the float height to spec with the hammer in the picture.
Actually the hammer is there to prevent two reprobate Bassett Hounds and a Irish Wolfhound pup from jumping up and pulling the whole lot onto the floor when I turned my back.

Basset Hound proof..  In my dreams, nothing can withstand a Bassett assault.

Hopefully, it doesn’t hurt too much now so we can chuckle along with you?
I see and hear the word “sod”… can you explain what/who sod is? Over here in the US, it’s a rolled up piece of yard… instant yard? Thank you
Sneezles61

Can mean a difficult person (he's a right little sod), or an expression of frustration - sod it is a bit like feck it, bu**er it etc.

Well said T

cliff