My dirtbike bogs down right when the power band kicks in. what could be wrong with it.?

Question

it is a 2001 yz 125. It starts good and has good spark. same fuel mix i have always used.

Answer 1

Not sure if I can answer this one, but I'd check for fuel flow, possible filter problem or it's possible your ignition is giving you problems. How to check this would be to check with timing light & see if the spark is fouling out. Could be there's some crud in the float bowl, who knows? All are easy to check, wish you well,

If it's two cycle, what type of intake reed system could it have? Reeds do mess up at hi-rev if they're slightly open.

Answer 2

Problem with the power valves.

Remove the covers and move the linkage, to see if the power valves are operating.

Problem with the governer.

Re-install the front cover and start the bike.

Rev it up to see if the governer is moving the linkage.