50mm kit

[scoot]

Having a problem get up to 40mph with 1.5 spring ,50mm kit and big valve head. also with 24mm carb. the carb has 95main and 38 pilot .it has a scrappy dog exhaust on it . has no rev cdi and coil. i know that i have to change rollers they are stock. also how hi should it rev up when going down the road its at 6.5 rpms when it gets to 40. the plug is burring good also to add to the list when at idle and u rev it up it goes up to8.5 to 9.5k rpm and cuts out to about8k and revs right backup and cuts again. it has a no revlimt cdi. also thinking of doing a gear change and different rollers would like to see a good 45-48mph before that on a flat run :help:

[90GTVert]

Might be lean. I was up to a 100 or 105 IIRC on my 50mm kit. I had a cam and had port matched stuff, but I was making good power into 8-9,000RPM with mine. At 6500, you've got a lot of room left. You should be able to get 50MPH with the stock gears. I was about 310lbs at the time when I did 50 on flat land. You can check out the Sunl thread on page one in the builds section, skip to the end area, and see how I modded the vari to squeeze out the last bit.

[reveeen]

Just, well, a "dumb" thought really...... have you got the vacuum port hooked up on the carb (the one on the right side, up high on the carb body, that the 50cc carbs don't have)?

It's the one you see, second photo, just above the throttle cable bracket:

www.partsforscooters.com/125-150cc-GY6-Carburetor-169-49?sc=9&category=354