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

[Terrotmt1]

Spent some more time with my follie francaise today.

Rigged up a small reservoir to by pass the tank as I had some fresh petrol and a precise 3% oil in it.

Tried to start it with the battery/coil set up. Nothing. 20+ kicks, nothing.
Removed that lot and tried the magneto. during the 20+ kicks I had a few peeps and then it started and ran. Revved well but sounded 'heavy', you could see and feel every cycle at low revs, smokey exhaust like a bad 2 stroke of old.
Starting technique is wide open throttle, a few kicks on choke, off the choke and pray/ swear each kick.
20 kicks is about my threshold of energy and enthusiasm, it was 30.

So, where are we?

Timing is smack-on.
Fat spark with Batt/coil test
No start with Batt/coil

fuel is fresh and mix correct, big Chinese carb.

I have been given the contact details of a proven 2 stroke specialist who is willing to chat it through with me. Next step for Tuesday as he is racing this weekend.

Time to play with the mighty race car this weekend for me, so will leave it alone until Sunday.

April 1st! Who knows what might happen.

[mini-me]

#1 it is "a bad 2 stoke of old"
#2 it is a 60 year old french workmans machine, it will never run like a sophisticated modern two stroke.
#3 why not fit a reed valve to the inlet?









####3

[mini-me]

If its any help this guy can't get his engine to start either.

https://youtu.be/vJoMs1xOUpg

[chaterlea25]

Hi Terrot and All
Just a further thought?
When started you say that there's lots of smoke even with the new fuel ?
Try removing the silencer as it may be blocked up , ?
Some years ago I was given a 2 stroke genny that would not start, exhaust 99% blocked so the engine could not suck in any fuel/air

John

[Terrotmt1]

Thanks for the thought John, the silencer is a new one from V Services for a 2 stroke!

I think this is back to poor primary compression, poor crank seals etc.

[Rex]

Starting technique is wide open throttle, a few kicks on choke,

That's likely why it sounds "heavy" (four-stroking?).
Not many vehicles start WFO and to do that with the choke closed is bound to over-richen the mixture.

[Terrotmt1]

Take your point, but it sounds the same after minutes after choke closed off, i.e no choke effect.
The 2 times it has run on the Villiers carb, it sounds better, same starting difficulty though.

[The Artful Bodger]

I don't know how old you are but. In the old days every vehicle needed a particular starting technique, some liked half choke, some a couple of pumps on the throttle etc. Many old bikes are like this, my experience with the Bantams is they need to be flooded, well and truly flooded with the tickler, choke and a touch of throttle.
  You mention using full throttle to start, this is only of any use if the engine is flooded as it lets the maximum amount of air in at kick over. Normally the bare minimum of throttle is used for starting from cold as this acts as a choke in itself since the air passage is mostly blocked.
  A little throttle, maybe 1/8 of a turn of the twist grip will give higher than tick over revs. as an encouragement for the engine to start but not a great gulp of air that you'd get from a wide open throttle. As I said, full throttle is the way to go when flooded but not at any other time.
  By changing the carbs around, trying the battery coil and having about the same amount of luck?? I'm not saying you won't have seal problems, but petrol straight in the plug hole, now starting with about 1/4-1/2 throttle and no choke (as the combustion chamber is now rich) you have bypassed the involvement of the seals to get it started.
  Since the jetting of the carbs you have is an unknown for your particular engine you might well have running issues once it starts, however unless they are excessively out it shouldn't actually stop it from starting once you know it's foibles as to throttle position, choke position etc. that it wants to start with.
  Once again, a fast bump in second gear flies the engine over much faster than with a kick start and often overcomes any slight flooding issues, weak magneto spark etc.
Colin

 

[john.k]

No 2 stroke will start without crankcase compression,because air will be drawn in thru the seal in preference to the carby,and then any mixture in the case will be blown back out the seal rather than thru the transfer port....In my experience a simple test is with the head off,you should get a pulse of air in the face as the motor is slowly turned.If the puff had no force,then the seals need replacing,and the motor will be near impossible to start normally..............The strangest 2 stroke I ever struck was a Rabbit scooter with a diesel engine......it used to blow puffs of black smoke and smoke rings,because the crankcase seals were worn.Started OK though,as the fuel was squirted into the cylinder mechanically.

[Terrotmt1]

I'm 66 tomorrow! I was hoping for a 'Colin Rosette' on my birthday.

My first Lambretta was a pain but I found the knack, my second was dead easy unless flooded then a pain all the time. My third was tricky, but would re-start really well and run well too, but everything was fresh, cylinder, piston, rings, bearings, seals etc etc.

Right, this bike:

I will try this afternoon the petrol down the hole again since I know the sparks are there at the right time.
Good result or bad, I'll try the 1/8 throttle, no choke. The big Chinese carb has a modern choke flap that all but covers the inlet diameter when fully applied.

If all this fails (and it has in the past) then I see the next move is to remove the engine, split the lot and have the cases machined for lip seals or better still, O rings.
Bonus is I can make them on my trusty Drummond lathe.

Well, the last 10 mins have been amusing.
Neat fuel done the hole.
nothing, but a hint sometimes it just might fire. After that 1/8 throttle, ful to carb connected, no choke, nowt
Pause for a swear or three, fuel down the hole, each time about a level tea spoon full, and nothing. Removed the fuel from the carb, so carb is full.
Kicked it over about 10 times and it fired and ran beautifully, no fuel to carb just fuel in the lower crank case from the spoon fulls previously. It revved to command, ran for about 1 minute sounding nice and 2 stroke and petered -out as the bowl was dry by this time.
Exhaust at the head leaks, and a black oil was leaking.
This all focuses on the mixture?
When the conditions are right it runs, when all the essentials are in-line it will start and run well.
Is this big Chinese carb simply too rich for it?

Will try the Villiers carb now and see what happens.

I think the O ring will be more effective.

Here is the felt seal on the clutch side and the brass bush on the mag side. I can have an insert made to substitute it with an O ring in the same place as the felt.

And similarly, I can remove the brass bush with the helix machined in it's bore and insert another but with an O ring in it's length.

[mini-me]

Take it to the top of the steepest hill you can find, drop it into second and force the bugger to run.

Many happy returns for tomorrow,,Boy ...........April fools day too

mind you, at 66 you should have learned when to admit defeat.?

[TGR90B]

After nearly 150 posts on the topic with no solution I should buy a pushbike.

[Terrotmt1]

This is the next project, must be easier than this Terrot.
More French Crap bought from an antiques dealer in Dover from the back of a van, just like Colin likes 'em. Oh, and a non runner I think, but I haven't tried it yet.

Closer to a push bike?
It will be an 'oily-rag' restoration and I shall start with the engine first.

Nice to talk about something other than the Terrot!

[TGR90B]

Another bike, is there no end to this man's versatility?

[mini-me]

who the phuk is Colin?