Misfiring Hornet 250?

[Timmay]

Hello,

My hornet has started to misfire at mid to high revs (8k rpm and over)

The bike throws me forward as it looses power and then pulls as it regains power and then repeats. Letting the throttle out allows the bike to regain composure and run at lower revs.

The rev counter drops (to 1k-2k rpm) also even though the bike is still in gear and the engine is turning over which makes me think it might be a sensor which is failing to detect high rpm.

The bike runs fine up to 8k rpm, no problems pottering around.

I have cleaned the plugs and air filter but no effect. I will replace the plugs tomorrow but i don't expect to see any difference.

After that I expect I will have to replace the coils, leads, check the carbs for leaks ect and then find the crank position sensor and replace that.

Any other suggestions?

thanks to all in advance.

Timmay

[Icemaestro]

I don't know much, but could it be the fuel line? revs get high enough, can't get enough gas, causing engine revs to drop and then gain again as fuel comes in?

[Timmay]

Problem is fixed, four old spark plugs was the problem, I did a resistance check on each one and they ranged from 3k8 to 4k4, the new plugs were 5k8 to 6k4