Terrot MT1 Motorcycle restoration project

[smallspeed]

hahahahaha!.. judging by the prices (generally) the French still see terrot as a cheap / throw-away bike for getting to market and back

[911hillclimber]

Yes, I think you are correct, no wonder it was 'cheap' when I fell for it!

Anyone with an idea how to set the timing on this 2 stroke?

I have a fixed steel arrow on the magneto and a mark on the flywheel. The flywheel can be mounted on the crank anywhere.
So...
Would I simply set the engine to TDC and align the two marks?
This engine would have been 'thrown together' in period factory production, so could it be that simple?

[smallspeed]

If you put it together that way, can you turn it over and check everything "kinda makes sense"? I imagine there's either a split/mould line In the case which the flywheel registers to, or directly to the marking on the magneto. If you can fit the flywheel in whatever orientation you want, then provided you have something to register as TDC it should be fine as its only really a reference for you to work to..

Don't 100% remember off the top of my head how a magneto works, but I think it kind of charges while it rotates, then "clicks" (effectively closes points) to send the built charge to the spark plug? It will fire every rotation being 2-stroke, so provided its firing around TDC it should be fine to actually start it, right?.. ..then once its started and running you can tweak it to suit

Actually if you line up the marker on the magneto with the marker on the flywheel, then you can easily see the adjustment (adv / ret) as you make it

[smallspeed]

Is this any help?..

https://www.thoughtco.com/2-stroke-igni ... ng-3971677

[Cortina]

Yes, I think you are correct, no wonder it was 'cheap' when I fell for it!

Anyone with an idea how to set the timing on this 2 stroke?

I have a fixed steel arrow on the magneto and a mark on the flywheel. The flywheel can be mounted on the crank anywhere.
So...
Would I simply set the engine to TDC and align the two marks?
This engine would have been 'thrown together' in period factory production, so could it be that simple?

Timing ... yes !
1. Set points gap - hopefully you have figures somewhere. If I had to guess , set at 15 thou. When is this set ? ... with points gap at maximum opening.
2 Timing. Again I hope you can get a reading / figure off the web somewhere ... it will be a small number of mm before top dead centre. Use dial gauge to get top dead centre ... this is easy if plug is in centre of head and "facing" down ... if it's off to the side and at an angle ... you need to be more carefull.

What you "looking for" , is the moment at which the points gap starts to open ... this is your x mm before top dead centre position. (I assume it's obvious that if you are reading at an angle , then x mm on dial will NOT be xmm BTDC !!) ... grandmother , eggs , and sucking !

Being one of them foreign things , it's unlikely my circa 1960 forwards collection of MCMechanics will cover it !! ??

[911hillclimber]

Thank you both!
That guide is brilliant, and I'll use it.
The method seems the way I imagined it, but when I did my Lambretta the timing was realy awkward with a protractor on the crank and a light through the points to find the moment of closing the points etc.
It was very sensitive as I remember when I have my pair in '68....
I am aware of the running backwards trait and this is why I need to be careful.

The plug lead literally sits on a contact pad on the side of the magneto, the lights run all the time the engine does.
Delightfully crude.

I have another project in the shed that will be my first 'oily-rag' project and that is cruder than this little Terrot.

I have this from a 1952 manual. Can't translate it, so need to do more thinking!

[Cortina]

Points closing moment is irrelevant (my opinion)
Running backwards ... possible , very hard to achieve a) timing needs to be way out , b) design of ports etc , needs to be a "certain way" , c) you must be able to make the engine turn the wrong way at the start ... which is tricky if you are either pushing it forwards , or have a kickstart which is causing engine to turn wrong way for some odd reason ??.

I see plug looks central ... enough, and pointing right way , just hope you can find a flattish bit at top of piston , or else have a larger dia pointer ... where it sits is kind of irrelevant ... but you know all that.

Older low powered two strokes are not critical to thou's for these things , to run ok. Neither gap nor timing can be played with while engine is running .... so that method of tuning is out !

have fun

Alan

[Cortina]

PS , my French is bad , but I make that loosen screw A , adjust points gap to 15.6 thou !! with screw B , tighten screw A

no mention of timing , does back plate rotate ? .. if not , then how (if at all !!) do you adjust timming ??

[911hillclimber]

Nothing is adjustable except the points, and it is SO EASY to adjust to 15.6 thou!

Fact that nothing adjusts to me says you bolt it together, but if it is ok to be that 'rough' then why not key the flywheel to the crank in the right position when the piston is at TDC?
It can all be marked-up on the drawing board and put into the production parts from the outset so the production build would be dead simple and fast = cheaper.

Take the point about revers running. Some micro cars had reverse by stopping and restating the engine which would run backwards to reverse using the gear box I think?

Anyway, I need to find a bicycle pedal crank cotter pin to fit it!
(Terrot made a lot of French push bikes too, so raided the parts bin)

Bet I have to make one, the original pin was missing.
All pictures are during stripping the engine:

Not a flat top piston!



Magneto:



The magneto flywheel has a 'cam' on the hub, fixed to move the points.

[smallspeed]

If you need the document translating let me know - couple of frenchies in my office although both out this week..

[911hillclimber]

Thank you, my wife speaks fluent (commercial) French, but I'll give her some homework (when I'm brave enough..) and tell her you thought she could do it easy.

Off to Beaulieu auto jumble this weekend, might find some parts!

[911hillclimber]

Had a reply from a French man about this, but using Bing Translation off the internet results in this:

Charlie is a question for you...


Full throttle ahead (it is possible that the advance is fixed so we forget the controller) and put 5-6 mm piston, positioned behind the wheel to make take off the screws platinées. (Metal arrow on the spool) benchmarks and benchmark of driving should match. (the marker is in a hearing of the wheel is a line drawn in the axis of the crankshaft)


In any case on an EP that is like. Timing is different (7mm), but the method is the same.

Earlier Terrots had a manual advance lever, mine has nothing.

[911hillclimber]

So, my wife has translated it!

the piston is put at 5-6mm, you position the flywheel so that you can loosen the points.
The references ( metal arrow on the bobbin or magneto) and the reference on the flywheel should correspond.
The reference on the flywheel is a line in the ear shaped cut out in the flywheel, it is a traced line in the axle of the crankshaft.

I gues this means the piston is set 5-6 mm before tic and the arrow and the flywheel mark should be aligned.
Not sure where you set the points!

[smallspeed]

5-6mm btdc is quite a bit - I think that article I found said 2mm, but its prob a lot newer motor so perhaps the terrot makes up for lack of static compression with some extra "dynamic"
Look forward to tomorrows start-up video

[911hillclimber]

Yea, right!
Autojumple very soon, motor club Driver School for my hill climb and several other things too might get in the way!
Rough being retired.