Help! New top end/electrical, lost 10MPH & power
 

My 150cc qmj was getting harder to start (but ran great when warm, 57 mph) and idle was all over.

1st step: replaced cdi, coil, plug, fuel pump, carb, air & gas filter. Didn't make much difference.

2nd step: tested compression, about 32 psi. Replaced piston, rings, cylinder. Now have good compression and it fires right up, idles perfect and runs smooth, BUT...

It now barely goes over 45 (and takes longer to get there) and during wot it will bog for a second or two.

So I now have great compression but less speed & power. Any idea why?

Looks like you've replaced pretty much everything. Perhaps a vacuum leak/fuel delivery issue?

Most likely your carb needs to be adjusted.