Starving for gas maybe?

[Mpgmotobiker]

I have a brand new RB80 black motor. Its suppose to have a bigger bore intake. It also has a stock carburater on it. It has no power. When it gets up into higher RPMs it acts like its out of gas until the R's go back down. I can coax it up a little higher but it just doesn't want to go. Help.

 

[crassius]

Have you put on enough miles to seat the rings yet? Brand new motors run like crap till then.

 

[Bikeguy Joe]

No necessarily. I have had some that make a little less power, and maybe vibrate a bit more until broken in, but they don't "run like crap".

Things to check include gas cap venting properly, float height, and proper carb setting.

Also, it could be four stroking, which is common. A two stroke SHOULD break into a four stroke/two stroke "break" when there is a light, or no load on it.

 

[maniac57]

Wait till you have at least three or four tanks of fuel through it before you start tuning. They need to be broken in first.