Terrot MT 1, 100cc 2 stroke: non-starter!

[The Artful Bodger]

First things first, is the plug wet? If so, the best bet is another plug and try starting the engine with no choke and a handful of throttle.If the plug gets wet again then the crankcase is probably overcharged with petrol. If there is a drain plug then drain the crankcase, if no drain plug then kick it over fast a dozen or so times with the plug out, make sure the choke is off. I've found the only way to clean a wet two stroke plug is to sand blast it hence change the plug if it's wet. Once the engine has run and is clear of excess fuel, the wet plug (after heating it or blowing with an airline to clean it) can be used again.
   If the plug isn't wet then try a T spoon of petrol directly down the plug hole, re-fit plug and kick with no choke and around 1/4 throttle, probably will take 3-4 kicks. Any engine will run without a carb. with a little petrol down the 'ole, for a couple of seconds.
 If none of the above works then look to your ignition. If it's just getting a bit prissy having been left for a while, try bumping it in second gear. The faster the engine turns over the fatter the spark will be from a magneto, might be enough to kick it into life?
 

Colin
 

[mini-me]

In my youth I have started a carb-less Bantam with a hanfudl of petrol soaked rag held over the inlet; it was enough to get some encouraging bangs.

If you get beaten by a decent french floozie it costs a lot.

[TGR90B]

You should be able to bypass the magneto. Temporary wire in a battery, coil & condenser through the existing points. It will eliminate one element at least. I'm assuming you renewed the crankcase seals during the rebuild.

[Terrotmt1]

Thank you all for these helping words!

I will do as Colin says, and add:

The engine I rebuilt from the crank out last year. The two crank seals are woefully weak as a design.
The mag side is nothing more than a close fitting of the crank and the case fitted with a sleeve which had a light helix machines in the sleeve to retain the oil in the fuel to give a seal.
I have added an O ring to help re-enforce the seal.
On the clutch side there is nothing but a felt ring which I soaked in car engine oil.
Thus primary compression is weak.

The design of the kick start is weak too, a good thrust will turn the engine over about 3 revolutions so not much suction is built up through the carb.

The plug is most time wet after a good work-out on the kick starter. In the past I have removed the plug and cleaned off with carb cleaner and a good few minutes to air-dry.

I have tried neat fresh petrol down the plug hole with little benefit, certainly not combustion.

I do have a good long straight road outside in a quiet cul-de-sac so a bump start is possible, but if that works and a kick start fails, the bike is not right.

The stream of sparks seen when kicking over the engine, plug out, is impressive, fat and blue. It is there every time you kick it over. As I say, the magneto was re-magnetised by a specialist in 2 strokes, Villier Services late last year while I battled with this issue originally. There was no spark before they did this.

The lights work well when the engine ran last year. They are 'on' all the time, there are no switches on this budget £2000 bike!

Hope to have another go at the bike 'carb-free' tomorrow using petrol down the hole after purging the crank case as Colin says.

When it ran last week by surprise it was smokey, 2 strokes smoke (I'm an ex Lambretta man) but this was quite bad. I may have too much oil in the fuel? Throttle response was good mind.

Got to get this fixed asap. I have a Peugeot BIMA to do next, and someone on here has offered me £100!

The plug gap is 20 thou, the plug is the original or at least very old.

[R]

You should try a NEW plug, even if its not quite the correct grade, as a short term try.

I learned that one very early on in dealing with old bikes - a spark outside is no guarantee of anything when it comes to reliable starting. And your story sure reeks of that....
Have fun !

[mini-me]

excessive smoke points to my idea about fuel in sump?

[Terrotmt1]

Just tried all the Colin tricks.

Vented the engine with 12 good kicks, no carb, stank of fuel, so wet sump theory sounds good.

Cleaned, dried the plug, tea spoon of fresh petrol down the plug hole.

Refit plug and 12 good kicks.
Nothing at all.

Put petrol-wet rag into the inlet port, kicks, nothing.

Fitted a new 2 stroke plug, petrol down the hole, nothing.
Bought some parts to have a go at the original carb, but also a second hand AMAL carb in good condition which another has used to get their Terrot going and it worked.

Total cost, £35.
Ordered the skip.

[R]

Fitted a new 2 stroke plug, petrol down the hole, nothing.

If petrol down the plughole (how much, just a teaspoon full ?) with a new plug doesn't produce even a pop, then the problem is in the ignition or ignition timing.
Checked the timing, tried cleaning the points ?

btw, the fuel down the plughole should be 2 stroke fuel - ie with a dash of oil in it.
Or it washes the ring seal off the bore, and out of the main bearings...

[Rex]

Agreed. Petrol down the plug 'ole eliminates carb, crankcase seals etc, so then it's down to plug, spark or timing.
(I can't believe you didn't try a new plug before though!)

[Terrotmt1]

Plug is the original, nice condition, and delivers a fast stream of sparks...but so does the new one!
But it eliminates the plug.

Fuel is a 2 stroke mix, I squirted about 1/3 tea spoon down the plug hole each time I have tried.
The timing is set at 5mm btdc, as specified in the bike's handbook.
In the past I've tried 2, 3 and 4 mm, no difference.

I checked the timing again 2 days ago.
Points are 14 thou when the heel is on the cam section.

So, I will recheck the electrical side tomorrow.
Not sure just what I can really do different.

I expected some kind of a pop or burst of running, but dead.

[TGR90B]

Either try my coil suggestion or get a new magneto coil. This could go on forever. It won't get fixed by you keep telling us what doesn't work.

[Terrotmt1]

There are no spares to be found for this bike, even on eBay.France.
This must be the rarest of all Terrot bikes and one of the most unpopular models too.

I'll report back later when I've re checked the timing.

[mini-me]

Regardless of the make of bike in this thread  the adverts that claim "rarest of the rare!!!"  "only a few made !!!!!" "one of only three known survivors" before going on to price it at some astronomical price do give me a lot of enjoyment.

Its like that chum because it was a pile of poo when new and were lousy sellers.
One reason I enjoy reading ebay ads is for the amusement.

Terrot were renowned for some quite good in their day 4 strokes, up to 500cc; there were lots of two strokers around in France back then to chose from,possibly they went to makers with more of a reputation for their smokers? Or cheap, the french are famous tightwads.

From my own experiences with buying french bikes in france I can tell you that if it had any kind of desirability they would not have sold it to us Rosbifs; I have personal experience of being asked an inflated price for a bike because of that,they don't want to export their best stuff and  they are well aware of the  absurd prices being paid for bikes here.

My offer of £100 still stands

[mini-me]

I assume you have found this?

http://www.terrot.org/doc_notices/100ccMT1_125ccETD/100ccMT1_125ccETD.htm

and this?

http://terrot.dijon.free.fr/GrosPlan/100MTR.html

[Terrotmt1]

Yes, the story of the whole restoration is on the Terrot.org site, and the French contributors had little to add to resolve my woes.

http://terrot.org/forum/viewtopic.php?f=1&t=19164

I bought this bike for a challenge, and so it has proven to have been an excellent choice!
The '74 Honda Sport I did before the MT1 was a lovely bike. cost a fortune to rebuild via David Silvers and sold in 2 days.
The Lambretta TV3 before the Honda cost a fortune too, and sold in 3 hours!

Those bikes have a huge spare part back-up even if expensive and poor quality in general.
However, the parts for a Terrot MT1 is another thing.

I did not buy this bike because it was rare and thus worth a fortune and I would make a massive fortune.

So, back to the tech side of this.

I have followed the suggestions and have reported that nothing has worked.
In Nov last year it ran several times for long periods with the large Chinese carb.

Last week after aborted tries, the bike ran in the 'November state' by chance the morning after a lot of attempts to start/flood it.
This supports:

Excess fuel had vaporised enough for the mixture ratio to be good enough for ignition.
It ran until the float chamber was empty, I had forgot to turn the fuel on..
This morning I have cleaned the Villiers carb I now have which is in very good condition. I will have to make an adaptor to fit it, but maybe it will work.
I have checked the timing @ 5mm btdc so the magneto flywheel is in the right timed place on the crank, thus the flywheel has not slipped on the taper on the crank.
The points are 14 thou gap with the heel on the 'cam' which is a raised land of steel welded onto the flywheel hub by the factory.

The condenser is good and with the plug (old or new) out of the engine the sparks are good when you spin the engine on the kick start.
This must prove the re-magnetised (Oct last year) mag is working.

Thus, I am typing this mid Friday morning not knowing what else to do.

If the timing was far out (ie should be 3mm) then surely the engine will splutter or show some sign of combustion?
The point gap can't be too far out/clean either as the spark is there.

Putting 1/2 a tea spoon of fuel into the combustion chamber is too rich, it ideally should be 14:1 iirc, but after 12 or more kicks that excess would be gone and a whiff of fuel left ready to ignite, but nothing.

Last point would be compression.

Engine has new rings and a tight head 'gasket' (copper ring) so compression is as high as can be but certainly not very noticeable on the kick start, but you can feel the difference with the plug out, so maybe this is as good as the compression gets.

I've run out of ideas, so going to replace the big Chinese carb and see what happens.