Terrot MT1 Motorcycle restoration project

[Ashley James]

Indeed, they are now in Telford, quite a company.
I am now waiting to hear what they can do.
Plan B is to buy a pair from chambrier in France.

I bought a set of MG TA pistons off them in 1966.

[911hillclimber]

Cripes! I was 14 then!

Thorntons can't help me as the rings are too small for them to stock. They can get some made, lead time is 12 weeks, no cost offered, SO, plan B, buy some from France!
Just back from a nice day out in the Boxster, so cool, calm and relaxed.

[Ashley James]

Can't beat roof down Boxstering.

[911hillclimber]

Indeed!
All parts now ordered from France, hope they come quickly!

[911hillclimber]

Memories! One very dark cold winters night late last year...

[911hillclimber]

Wish I had NEVER seen this sodding bike ever!

Got my new rings from France and had to fit them to go inside the cylinder etc etc but all in now after an hours struggle.

Excitedly put petrol in after checking I had sparks. Squirt of Quick-Start and...absolutely nothing.
Checked points gap, checked timing and checked the fuel flow in the carb, all seem ok.

Took carb off, squirted QStart down the inlet and nothing. Dropped neat fuel into the head, nothing and any other combination I could think of.
Nothing, dead as a door nail, compression feels like it did before the new rings!

I have regular sparks.
I have compression (if I don't I have no idea how to get more)
I have fuel, and I believe I have a spark at the right time.

Just WHAT have I not got?
Apart from the sense to chuck it away.
Thinking of simply donating it to the midland motorcycle Museum, bet they haven't heard of one either.

[Ashley James]

The most common reason for elderly two strokes not to start when cold is crankshaft seals leaking. Usually they have enough compression to run cold but pack up when hot. I remember from when I was a child because of Atco lawn mowers and Hickling Broad. We were stranded for about half an hour in the middle while the Seagull outboard cooled or I couldn't finish mowing the lawn for the same reason. Always assuming the timing isn't retarded because the main bearings have play.

It's difficult if you're not there so sorry if I'm talking crap.

[911hillclimber]

I thought it was primary compression missing (crank case not sealed) but I get a suck feeling on the hand when covering the inlet and turning the engine over, so I presume there is some low pressure in the inlet for a while and there is a good push of air with the plug out so assume the air in the case is being pumped to the combustion chamber.
Crank bearings good!

I wish I knew what to do next! (that is constructive)

[Ashley James]

The only thing left is the timing by the sounds of it.

[smallspeed]

Knowing how long old kick start bikes can take to catch, do you know anyone from hillcimbing who has one of those weird "roller" things you sometimes see people starting old f3 JAP 500's with?
Maybe you can put it in gear and run it on one of them so you have more of a constant running situation?

[911hillclimber]

I know the device well, but...
This is a simple little low cost production bike of the 1950's.

The factory would bolt them together and send to the dealers, who would add crappy fuel and kick them over. They would have to simply start.

I can now say the piston and bore are as tight as can be.
The magneto and condenser are full of blue sparks and I've had 2 belts off the HT lead, so some volts are getting there.
Points are tricky to adjust, but I think are 0.4mm +/- 0.1mm
Timing is set to TDC, then back the engine off until the piston has dropped 3mm from TDC so, '3mm BTDC'
The flywheel and static marks are aligned and the flywheel tight.

Fresh fuel.
Carb is clean and all drillings are clear, jets too.

This engine is so simple there isn't anything else to do!
It should run and it does not, and I don't know why.

not sure this is worth it. It is cosmetically good, UK registered and if a runner could be used on the road.

might put it up for sale as a non-runner and put it down to experience, will cost me a £1000 to see it gone so I can get on with my 911 re=paint.
Very frustrating.

Here is one that works:

https://youtu.be/91cr38G0WnQ

[Ashley James]

Old two strokes can be a nightmare

[911hillclimber]

indeed.
I have wondered if the magneto circuit is stopping it. The bike should have a kill button to stop the engine. There are no switches at all and every diagram I've found of the French magneto has no kill switch anywhere.
I presume you stopped the engine by stalling it? This seems crude even by 1950 standards.
There must be something fundamentally wrong somewhere, but as I get a run of sparks, have petrol in a clean carb and some kind of compression, it won't do anything at all.

Really annoying to be set back by a little fart of an engine.

[911hillclimber]

Decided to try again, with no luck I should add, but:

I took the head and the cylinder off again to see that the transfer passaged were all clear and indeed they are. When I originally took this heap apart the exhaust ports were almost blocked with carbon, so I know it ran once upon a time.
Bottom of the crank case is clean. The parts diagram for the engine lists no seals for the crank ball bearings and this has always made me suspicious. My 2 stoke Lambretta certainly had crank seals.
With the barrel on I found tdc and 3mm Btdc and set the flywheel (again). As with all 2 stokes, deciding where TDC actually is is trick, you can be 5 crank deg out easy.

Put it all back together. I did all this as I still am not convinced about the compression 'strength', seems weak to me.(despite new rings)

Took the carb apart.
In all this chaos, the plug has NEVER been wet with fuel, always dry.
All seems well, all holes are open, all parts present.
Found a girl in France with a modified MT1 and she has fitted a Dellorto 21mm carb instead of the original. £32 from Hong Kong....

Put it all back together, and nothing is alive.

[Ashley James]

It has to have crankcase compression. The ones I rebuilt over fifty years ago had leather oil seals as I recall and unless they had plain bearings like the Bantam. The timing side one of the Bantam would wear so badly that you had to get it going and then adjust the points for maximum speed, which would suggest a seal as well, but I cant remember. I do remembers the starting problems leaking seals caused though.

Compression won't be very high because there isn't much stroke after the transfer port(s) are covered. Japanese bikes used to quote about 7 to 1 for this reason and they were all 100bhp/litre not 3.