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

[TGR90B]

What success?

[john.k]

All this reminds me of a scene some sixty years ago ,me and my brother used to go round a friends place ,and  tinker with a little non descript 100cc bike ,not a Villiers ,dunno what it was........anyway ,we would get it going and  run it around the streets ........only for  a while ,because the flywheel keyway was flogged half way round the shaft,and when the timing shifted it would stop....till next time..........I had a monumental buster on it ,onlookers say it cartwheeled,all I know is I ripped the insides out of both knees,and skinned my arms very thoroughly...........I have hated little two stroke bikes ever since.

[mini-me]

Ha!

Sane folk describe it as pissing into the wind.

[Terrotmt1]

But it sums up my position!

Awaiting a response from carburologue.fr about parts for the 903 carb, namely, do they have new needle, jet, main jet and piston chanber top, but notice the real difference of the jet they have in stock and my carb's jet, really different..
The jet in the carb now has 2 machined flats that allow fuel from the bowl feed to flood past the actual main jet, up the sides and into the volume just under the top of the jet neck sort of by-passing the screwed-in main jet.
The new one does not seem to have these 2 cut-out slots...

[Terrotmt1]

Seems Carburologue do not have parts (that I need) for the 903 AMAC carbs.

This carb must be worth £1,000,000 as it is the only one in existence.

I think I need to re-group and focus on the new Dellorto carb I have (Chinese rip-off) and have found a source for different size jets for £3.28!
This engine has run for a good time just 3 times after a lot of kicking about 2 years ago (lost count) and the engine then throttled well.

The coil was the old one and the points the originals with new contacts, so the rest of the engine now spruced-up, the starting might be ok..
Doubt it, but this may be down to mixture.

The new jets will give me some adjustment that might give me a fighting chance.
Everything is new and some others have fitted them with success.

In the meantime, somebody else is sending me a lawn mower carb to try!

A running engine will be a nice Xmas present.

[mini-me]

tried a BSA bantam carb on it? Looks very similar.

[Terrotmt1]

Yes, I looked closely at the Bantams at the National Classic Car Show where the Bantam Club had a big display.
The D! (first Bantam?) has a carb really similar to this AMAC 903.
Can't find one yet.

Have found a supply of jets for the Dellorto and they are on the way, and today had the thing running (!) but still too rich and very poor response to the throttle.

The needle has its clip right at the top so the needle is DEEP down in the jet tube. I've been moving the clip up and up by 1mm for several goes and then the float up and down its needle.

After the engine dies I remove the plug, it is always wet or certainly damp and black and at the same time remove the sump drain (that you told me to fit) and now just a small drop or 3 of petroil comes out. I can't get it dryer.

Will try a smaller hole in the top of the jet tube to create a smaller aulas than I have. This will weaken the mix further I think.

I have the lawn mower carb coming soon....

[Rex]

Not trying to teach your grandma about eggs here, but carbs have precision drillings, jets and needles, and hit-and-miss experimentation with sizes etc probably isn't going to be conclusive.
What is certain is that the engine is running far too rich, so I would suggest either a complete carb (Bantam, Villiers etc) appropriate to the engine size. There's too many variables in your situation now.

[Terrotmt1]

Rex, totally agree.
The Dellorto is the closest new carb I could find with nearly thesamechoke diameters as the original..
It has not performed.
I have closed the Dellorto's main jet to close to the originals but do not have the very fine drills required, so have to experiment to try to refine things, which I am trying to do here.

I can reduce the hole dia in the top of the needle tube quite readily in the original.
The jets coming for the Dellorto will allow me to change the jet with accuracy, so fingers crossed.

I am surprised how rare these AMAC carbs are considering they were used in quantity on many bikes in right and left hand configurations etc.

No spares, no ebay wonders, nothing at all.
Toget this done I have to try different things with what I have.

[mini-me]

I have left a loaded revolver on your desk, now go and do the decent and honourable  thing.

Man up, and get it over with.

[TGR90B]

What with this on here and Money for nothing on the telly it really is a depressing afternoon.

[Terrotmt1]

It's not in your garage, you are the lucky one!

Got a plan for tomorrow to weaken the mix, maybe I can get the plug actually dry and pale which will be a first.
Got to crack it so to move on to the next French Folly, but I won't put that saga on this forum; see, told you you were the lucky one.

Mini: if I can't get this thing to fire properly, I'll never fire a gun.

Anyway, instead of getting rid of me and hence the bike, find me a solution!

[mini-me]

find me a solution!

# Buy a boat
# buy a long length of chain
#attach chain to terrot.
# you have an excellent anchor.

failing that donate it to the Green Party,after all it uses no fuel.

[Terrotmt1]

Been lot said no, they have read this thread and we're still recovering...

Tried to weaken the carb this morning.
No success despite the needle to jet diameters being almost the same!
Changed the needle position, changed the float position all to no avail.

Goodness knows how to make the mixture the correct ratio.

Awaiting the Dellorto jets so I can try that carb.
What fun, soooo very satisfying.

[john.k]

I seem to remember the JAP twostroke motor on a Ransome lawnmower had the same carby,or one very like it...........although its funny a cheapo Victa mower will run with a floatless plastic carby that clips together ,no screws,but a proper piece of engineering wont work in the least.