Vespa Bravo, will start but only on choke, dies when warm

Moving this to a "Repair" thread , originally a part of a "Performance"-question.

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Hey fellas!

Vespa Bravo. I tried the suggested setup: Dellorto 13/13 carb, malossi air filter and tecno circuit. Nothing else is done, everything else is stock.

With the 58 jet that came with the 13/13 carb, it four-stroked a lot at WOT which I interpret as a too rich jet. So I tried 52, but now it is hard to start, have to use choke which I never needed before. Even when riding I have to push and keep the choke, if it comes out, it dies. And even when holding it, the engine dies as soon as engine gets warm or slightly uphill. I am afraid of riding it, fear of breakdown.

I got the suggestion that it's lean, but how the hell can it be lean with 52 when super-rich on 58, can't imagine that.

I have no clue what to do, what are your suggestions?

Regards!

Re: Vespa Bravo, will start but only on choke, dies when warm

52-58 is a large leap for a 49cc.

If you start it with the 52 and run it on the stand at WOT then slowly apply the choke does it do nothing or pick up

If so then yess you are too lean. (dangerously)

Get your self a spread of jets in between those numbers.

In the mean time you can just fourstroke on the 58.

Re: Vespa Bravo, will start but only on choke, dies when warm

Thanks man!

Yea, the 52 won't even start now. I figure I might have air leaks, makes no other sense. I have 54 and 56 too, i'll swap to 56 and see tomorrow.

Any other ideas to try while im out there?

Re: Vespa Bravo, will start but only on choke, dies when warm

you need to get a accurate compression reading. The dies when warm or under load sound like the 80-90 psi syndrome

Re: Vespa Bravo, will start but only on choke, dies when warm

now you suspect air leaks? did you read wiki,air leaks? I hope you have good luck.

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