Ahhh another jet query

Hmmm , I’ve just fitted up my PM evo 24 to my now run in Polini 180 PX150.

PM supplied me with a 108 , 105 & 102 jets…

I kinda expected it to be better with the bigger jets , as I took out a 98 that was in from when it was a plain 150cc.

Very poor stuttery performance with the 108 , slightly better with the 105 - and the 102 just gave me an easy 70mph.

Is this expected - and safe - as I don’t want to run to lean and mely the bally thing.

It depends if you have the cases ported and a race cranck.
But in any case you should give what your engine needs not what it sounds good to you. If it likes 102 then give it 102 main.

The PM expansion (for PX, it is different then the PM for T5) has already a curve more mid - low oriented then the SIP or JL.

To shift the power a little back and to have an engine fuller (more torque) you should go for a long stroke.

'k , thanks.

Jetting from bike to bike can differ.Why would PM supply 3 jets?

If it’s running well and the plug is fine then stick with it.[;)]

All exhausts behave differently and have power curves at different rev ranges. PM , sip etc make their power higher up the rev range than other aftermarket pipes. Check out the „B-Race“ pipe dyno graphs on his site

I had just assumed they were giving me options.
I’ll run for a while tomorrow and check everything.

Didn’t half take off from 55 to 70 mind…

Is there any way of shifting the power down a bit to a more mid range ?