Engine stopping at running in

[Supereibar]

Hello peeps, just finished this TV175 engine after a religning of the barrel and fitting new piston bored out to 62,4mm and new mazzuchelli tv crank.

Just tried the scoot around the neighborhood to see how it runs and I notticed the following:
When I downshift, the scooter suddenly comes to a sudden stop. It takes a few kicks to get her back up and running, but after another half a mile if will do it again if its on idle.

Any ideas?

J.

[rog60]

Wasn't there a problem with the old type delly carb stalling on overun or summit like that cured by plugging a drilling inside the carb.......................

[Supereibar]

I was more thinking of a problem with the bore being too tight wouldn't you think?.. I just gave up. I will dismantle the cylinder and piston and take it again to have a rebore. Any recomendations on tolerances?

[bristolmod]

Jaime!

now don't go getting all "Continental" on us

Does the engine just stop (carb/fuel tap problem?), or does it "nip-up" (bore clearance)?

Chris

[Supereibar]

Chris... sorry to get all "Continental" on you LMAOO!!!

Yes the engine comes to a full stop at low revs, it doesn't tick over.... I cleaned the carb, but I didn't remove the petrol tap, would you think that might be the problem?

What do you mean by "nip-up"? Don't take your "Mod attitude" on me Chris!

[Supereibar]

I forgot to add that I removed the mushroom baffle from the SITO exhaust... should I upjet maybe?

[cezeta]

nip up means that the piston is locked in the barrel and will not kick over. you should check your clearances on the build, all you need is feeler gauges which cost 5 euro.

so when you change down does the rear wheel lock up as if you a braking or does it die as if you have run out of fuel?

[Supereibar]

it dies like if I run out of fuel...

[cezeta]

its probably not you piston to bore clearance then. check that your tank breaths properly, i had similar problems with a tank that had a dented filler cap which stopped the tank breathing, all the time there was a vacume in the carb it was fine but as soon as the vacume stopped it conked out. in the time it took to pull over, take my helmet and gloves of the bloody thing would start again and be fine for a mile or so.

it was fuel flow or lack of it. the mile would empty the float bowl then when i pulled over it would trickle back in again.

thats one place to start checking anyway.

[Supereibar]

Also I don't think I have a 50 pilot jet as it indicates in the manual, tallest one I could find was a 48.... The engine is back on the 175 crank. The hamfisted twats that messed with it before had rebored it to 66mm and put a 200 piston on.