Piaggio Zip AC Jetting

[MellowDudeNZ]

Hi folks,

Have a 70cc MHR Replica fitted with stock airbox, malossi foam insert, Yasuni R and 19mm Dellorto carb.

Near sea level, 95 Octane fuel.

Currently setup with needle clip one down from top, #85 main jet, air screw set 2 1/4.

Runs fine across the full throttle range but has a stubborn bog off idle, .

What's other people's experiences with jetting/tuning of the same carb, jet sizing with same airbox setup etc?

Currently using malossi carbon Reed petals, appreciate any recommendations there also.

Setup is for decent daily commute, not race.

Thanks

[90GTVert]

Feb 2, 2024 16:07:30 GMT -5 MellowDudeNZ said:

Runs but isn't not great across the full throttle range.

For clarification, are you saying it doesn't run well anywhere or that there are parts of the throttle range that it doesn't run well? If it's the former, then the whole tune needs to be gone over. I'd make sure it idles and then start doing main jet tests before dialing in the needle and pilot jet. If it's the latter, then determine what range or ranges of throttle opening are performing poorly and use that to decide what you should be working on.

www.49ccscoot.com/faq/carbtune.html

[MellowDudeNZ]

Apologies, just edited that original post to make it more clear. The issue is splutter/bog off idle when taking off fast, once it's at 1/4 throttle it seems fine across the rest and fairly responsive.

If you progressively roll on the throttle at takeoff it's o.k, trying to get it to have more snap though.

So really just focussing on trying to eliminate the bog off idle for snappy takeoff.

Thanks

[90GTVert]

Most likely you can improve it with a mixture screw/pilot jet and/or needle clip position. Try to richen the needle by one position (move the clip down a notch in the needle). See what that does.