Mugello piston

[Danger]

Just blew a hole in my mugello stg4 200 piston which was a 66 A do I replace it with a 66 A or do I go 66 B plus what timing would you recommend as I'm going to have it checked the engine is as above with a pacemaker gearbox , jl3 pipe , af lightened flywheel , running a 30 mil delly open mouthed thanks in advance Darren

[drunkmunkey6969]

Replace with an A piston, set ign timing to 17, set carb up on dyno.

Also, set squish to 1.2-1.5 and comp ratio to 9.5:1.

Lastly......get fan cowl as close to fins as possible......

[Danger]

Cheers drunkmunkey

[Danger]

Ps we don't have anybody were we come from here in northern Ireland that dynos scooters thanks for your help tho dan

[drunkmunkey6969]

Ok....post your full carb settings and someone here will help get you at least into 'ball park' figures. We're a helpful bunch! Lol

[Danger]

Ok will strip carb tomoro to see what's all in it then I will post it up thanks again

[Danger]

The setup on my 30mil delly at the mo is. ,,,,, Float needle valve 350 ,,,, choke 70 ,,,,, idle 55 ,,,,, atomiser av264 ,,,,,, main jet 122 ,,,,,, slide 40 ,,,,, needle x7 ,,, which I've just noticed is on the top clip

[Special X]

I'd be happier with an AV266 and the X7 on the 2nd clip. If it's still a bit lean on the needle 1/4 - 3/4 throttle you could try an X13 1st clip. Mugello pistons have been known to be frail so follow Dans instructions re the compression, squish, and timing and all should be well.

[Danger]

Thanks special x have a few jets an needles , I'm also going to get the timing checked then reset ,,, ps all an any advise is greatly recieved

[faf]

Hi,just been reading this with interest as i have to replace my mugello piston,how do you measure and adjust the compression ratio?

Cheers