what size main get do i need plz

[vespa]

hi can any one tell me what size main jet i should be usin in my mallosi 166 casings ported 2 match 24 mill dellorto si 24 24 e carb scorpion exhast im running it on a 115 main jet at the moment many thanks

[paddyfitz]

I've done a bunch of close approximations to that setup. Usually starts with a 160/Be3/125 - to possibly a 135 depending on different motor parameters.
50-120 idle sometimes works better than the 52-140 idle the kit comes with.
Just a base point to start from.
Cheers.

[vespa]

do i stand a chance of the engine goin bang if i leave the main jet i have in now also what r the benerfits of up jettin the carb thanks

[paddyfitz]

Smaller jet = less gas. Larger jet = more gas.
The pipe you're talking about, setup with said cylinder kit & carburetor - in my experience work better with the introduction of more gas (larger jets).
This also tends to make them go faster & not blow up




...as quickly. ;D ;D