2 stroke topping out early

[JonathanC]

Hey guys I have the 66/80cc bikeberry engine with stock carb and expansion chamber. I’ve noticed that the engine seems to max out speed when I’m only at about 3/4 throttle and it will go about 25mph. Is this because I need to adjust the carb or is there another issue that I’m looking over. Any advice will help I’m still new in this hobby and I really respect all the feedback I get from you guys!

 

[WheeliePopper]

Just to add RE: air leaks. Start it up and spray a little brake cleaner around the intake and other parts. If it starts to die, there is a leak. Tighten and move on to the next possible leak.

Just don't leave it idling too long.

 

[JonathanC]

Are you letting off the throttle before pulling the clutch?

haha yes I’m not that stupid!

 

[JonathanC]

Does your carb have the O ring installed inside it where the intake tube seats into the carb???...It needs to be there in order to make a proper seal.

Yes I do have an o-ring

 

[JonathanC]

When I built the engine it said something about doubling up gaskets on the head? I just went with 1 because that’s all they gave me. My thought process was that maybe that was for the stock head and not for the upgraded one

 

[Whitewill1412]

haha yes I’m not that stupid!

I've done it. I am that stupid sometimes.

 

[DAMIEN1307]

When I built the engine it said something about doubling up gaskets on the head?

The double gaskets are usually the gaskets on the bottom of the cylinder between the cylinder and the crankcase.

 

[JonathanC]

The double gaskets are usually the gaskets on the bottom of the cylinder between the cylinder and the crankcase.

Would that be causing a problem if I only used 1?

 

[DAMIEN1307]

Would that be causing a problem if I only used 1?

Very possible.

 

[Chainlube]

Would that be causing a problem if I only used 1?

When you turn the engine over and look into the exhaust port is the top of the piston above the port floor?

 

[JonathanC]

I loosened the carb up and reseated it and that seemed to do the trick as far as the overrevving. As far as the throttle goes, I think once I get to 3/4 throttle at about 26 mph that’s the best that the engine can do on a 44 and with my big 240 pound buttmight change to a 40 tooth because I don’t want to sacrifice too much torque