Terrot MT1 Motorcycle restoration project

[smallspeed]

Engine looks superb

[Kneeslider]

Had the day to myself, so put the engine back together. not without some problems but it is ok so far.
The crank does not rotate 'nicely' and despite slackening off the two case halves and trying to find a sweet spot to allow the crank to spin I reverted back to the factory position which uses a 5mm dowel to locate the two case halves. The rest went back together quite well, the kick start spring and shaft needed some help and the clutch basket fowled the kick start ratchet, but shimmed the lot and all seems well.
Oddly, the kick start shaft passes right through the bottom of the gearbox oil sump and it has NO oil seal just a close fitting bore in the casting and the shaft has two precision ground lands.
This must be a total loss system!
Biggest problem now is how to time the ignition.

I have the mark on the magneto cover and the pointer on the magneto so I assume I set the engine at TDC and lock the cover with the crank nut??
I assume the contact breaker gap to be 0.3mm?
Need to do some research! I might just use the Lambretta 2 stroke timing values and method...

I know that I might be stating the obvious, but the crank is a bolted together type with a roller big end?

Have you tried to chuck one end of the crank in the lathe, turned it over by hand, while holding the conrod to stop it hitting anything, and then applied a dial gauge to the other mainshaft? That's how I always set up a two stroke crank. Could that be problem when you say that the crank isn't rotating nicely in the cases?

Don't take it for granted that the last time the big end had seen work, it was done properly!

Oh, and please tell me that you are going to replace that gearbox output sprocket! It looks rather past it.

[911hillclimber]

I wish it was superb...
Not 100% positive about the engine due to the variable turning resistance of the crank.
There is indeed no way of saying the engine was good when I took it apart, but the crank is the classic bolted together/roller big end design to which I've done nothing except clean the crud off it.
It is not a big deal to take it apart again, but I tried several ways to try to ease the resistance to a minimum and I'm not sure I would achieve more if I re-tried.
If the 2 halves of the crank were out then the turning resistance would be constant, mine has about 45 deg of sweep where it is greater than the rest of the cycle.
I'm pausing for thought.

As to the sprocket, yes, it is well ground but very evenly! The wheel sprocket is much better, both I feel are the 1950 originals.
I cannot find spares for this bike, even asking on the French site Terrot.org is getting me nowhere. Nothing like these parts on French ebay either.

This was part of the challenge, I could not restore this bike using a cheque book as I did for parts on my Honda CB 175 and the Lambretter TV 3, they are easy to do, just buy buy buy all the time!

I have to draw a line under the work on the bike by the end of the week to focus on the race car and it's first event on 25th March then I can resume or start the engine over again!

[Kneeslider]

The only reason I suggested looking at the crank again, is because I had exactly that issue with a 125cc Regent two stroke that belonged to a friend. It had ruined its drive side main bearing, and all the bits had ended up wrecking the primary chain in the chaincase on the left side of the engine. It was a low mileage engine, but the manufacturer wasn't exactly known for quality, so on taking it apart, I found that the two main shafts on the crank were almost 2 thou out. This type of crank was pressed together, and the big end was good, so a couple of hefty blows with a lump hammer brought the crank back to true. The crank on that bike seemed to run free, then bind in the same place in the manner you describe.

It looks as though your engine has a crowded roller with tapers on each side of the big end, secured with nuts on each end, the same as most British single cylinder four stroke thumpers. Check the crank to see if it is misaligned, and if it is, then fixing it might just be a matter of undoing the taper nuts and knocking it back to true.

Of course, you might have a bent shaft... That would complicate things, but it could be straightened if it were pressed out of the flywheel, straightened in a press, then pressed back in.

Good luck!

PS. Nice work on the carb!

[911hillclimber]

I suspect you are correct!
With a heavy heart I think it will have to come apart. such are the joys of old thing restorations!

I have 2 good 2 stroke shops close to me and one is very used to Lambretta cranks (pressed together) so might just take the crank to them for sorting, then make new gaskets etc etc.
The car was a mini adventure, and most enjoyable to do.

[smallspeed]

funny you're starting back up on 25th march - that's my deadline too! I got drunk over xmas and booked at track day like an idiot

[911hillclimber]

Then you need to get your head in gear!
Did the first round of cleaning my race car this morning, so about 30% done.
Hill climb cars can be very simple, bit like the Lola's driver...
Lots of detailing to do and a fat oil change.
Oh, and the first 5 entries to send in tomorrow now the Midland Championship is open.

[911hillclimber]

Got going again on the little Terrot MT1
I want to have this assembled and maybe even running by the end of April.

The little engine dropped back into the frame with ease the repaired cases lined-up perfectly with the frame lugs thank goodness.
Next task was the forks, always tedious but these are very simple and oddly (like many other aspects of this bike) they have no seals!
Fork yokes went in well and turn nice and smooth.

Put 75cc of Racing Fork Oil no less in each leg and it all screwed up nicely, surprisingly rigid!
The tool box next as it was quick and simple.

Next job will be the front and rear hubs/ brakes using new ball bearings and a new cup from California no less.
Assembly is very fast compared to the far more complex Honda CB 175 I did last, but I think things will slow down when I get to the wheels...

[911hillclimber]

I repeat this thread on the Terrot of France web site and I have been told by a French man that oil is not used on this model but grease.
This explains why there are no fork seals!
The Manual I'm using is a 100 and 125cc general book printed by Terrot in 1950 and the 125cc forks are oil damped, no mention of the 100cc forks being damped by anything!
The fit between the outer fork tube and the piston rod is quite close so I guess I just smear grease on both pistons and slowly ease the two together, the high speed shearing of the grease film gives some resistance to the springs oscillating.
So 3 steps forwards and 1 step back!
Oil out and grease on this afternoon.

Typical restoration process not isolated to rebuilding 911's....

[AndrewSlater]

Good to see you are making good progress - will be a great little bike.

So 3 steps forwards and 1 step back!

I'm just jealous you are making 3:1 , feels like 1:3 on my resto

All the best
Andrew

[911hillclimber]

Well, it certainly varies...

Did the oil-to-grease change in 15 mins!
Spent 2 hours trying to fathom out how the front hub spindle goes together as I have forgotten and have one useless picture when I took it apart.

The picture I have from the 1950 manual is hand drawn and lacks clear detail, all the adjusters drawn the same, all the lock nuts drawn the same, totally opposite to what I have on the bench.
Think I've cracked it now.
The bike had been re-assembled wrong when I got it during the 67 years of it's life in France!
This bike is so rare, even the pictures on Google are small and lacking detail so flying by wire and guess-work.

Have the wheels to re-spoke soon, the ratio will be a bit different then.

Perhaps I had better check I am using the right screws before someone notices..

[911hillclimber]

After a lot of trial and error I have managed to re-assemble the front and rear hubs so allowing me to re-spoke the wheels next.
Quite a game to say the least, but slowly,slowly catch your monkey.

Had the original shoes re-lined by the excellent Villiers Services not far from me, and not expensive either!

[Ashley James]

Is it LM2 semi liquid grease as used in steering boxes, Burman motorcycle boxes etc.

[911hillclimber]

Absolutely no idea!
Cannot find any info at all on what to use so I've put wheel bearing grease in for now.
It is all a bit meaningless as I suspect the grease will migrate down to the bottom of the fork tubes quickly.

The difference in engineering of this 1949/50 utility bike compared to my last one, the Honda CB 175 Super Sport is massive...

Just spent 2 hours lacing the front wheel, what a game but all laced. Just needs truing now!

[911hillclimber]

Managed to get some long hours on the bike this week doing the job I least like, lacing and trueing the wheels.
I had new spokes made and new nipples and a few photographs I took of the wheels before stripping them.
The lacing is quite different to my Honda and the rims are different too with the stagger and dimple of the spoke holes.

Did the front first as it seemed the simplest but became hard work to figure out the sequence. Spotting the symmetrical pattern is tricky but got there in the end with a run-out of 1mm. OK I think for a 30mph bike!
Put the brake on and the tyre which was fitted using soapy water , swearing and strong hands...

As light relief I fitted the rear mud guard and carrier frame all of which were really difficult. Terrot I think make these parts to be stressed when bolted together to achieve rigidity.
There is plenty of stress there now.

The rear lacing was really frustrating and took ages to get the sequence going but all turned out well in the end. I walked away from the task twice to save loosing heart.

Run-out is 1mm max and the tyre will be on today, followed by the handle bars and levers.

I need to get a new chain, some rubber parts and new cables. I hope to get to a major bike show on Sunday but a big race at Silverstone might stop that.