70cc big bore kit and Mikuni VM20 on an Urban Express?

[Buckeroo Bob]

Need a little tech advice on tuning the VM20 to the engine, ie. what jet sizes to start with. Don't want to order a whole drawer full if someone can give me a starting point.

[patthesoundguy]

Prob a 40 pilot and 95 main or thereabouts should get you in the ball park on an express. That's what I had on my 19mm dellorto on my bbk on my express and it was pretty close and the mikuni should be kinda close.

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[Buckeroo Bob]

I was "warned" (seems kinda harsh) to post this in the technical advice section. Guess I can reply to your advise by saying the jet numbers you give don't seem to be Mikuni VM numbers. Thanks for taking the time to reply, however. Next post will be in "tech section"

[patthesoundguy]

Of course mikuni jets and delorto jets are gonna be different but as far as I remember the jet numbers weren't all that far off. All you need is a ball park. I'd take a look at moped army maybe do a search for express VM 20 starting point, it all depends what bore you are running as well. The VM 20 mikuni is a very popular swap on the express so a starting point should be easy to find on moped army forum.

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