110cc problem

[jonas20]

Hello, I recently did a engine rebuild from 72cc to 110cc. I changed the crank, cylinder and the cylinder head. It starts up fine and idles decently. When I give it throttle the rpms from 2k to 4k go up smoothly, but after 4k it seems like it doesnt want to rev up. When riding it, it bogs really hard, but then all of a sudden the rpms rise fast and if u change the gears fast and take off the throttle fast it rides good, but if you let off the throttle just a little for too long it starts bogging again, what could cause this? I tried looking for air leaks, found none, carb cleaned, changed spark plug, the fuel flows good from the tank to the carb, also tried another carb.

[krat]

It sounds like your idle jet is right and doing its job. When you open the throttle for mid range the main jet is giving you everything it has, and when you open the throttle for full power you are cranking in a bunch of air with no additional fuel for the mix.

You need to increase your main jet size. I would suggest a 95-105 main jet. My 80cc runs real well on a 95 and my 150cc scooter with a 105 jet outruns my 250cc TBR7.

Trying a second carb, that is just like the first, just proves both carbs are jetted alike.

You also need to give the valve settings a second check. You want plenty of clearance for the fresh break in.

[jonas20]

Thanks for your advice

[david3921]

Krat's suggestions are spot on. What size carb do you have? My Tao Tao came with a PZ20.