fuel/air mixture

[thoryamaha22]

when i hold my throttle half open it skips and makes a bogging noise
i was wondering if u guys could help me fix it
thanks

[zuki]

what kind of bike is it?? what mods..year??
If its a smoker it usually means that its running lean

[Woody_393]

I agree, sounds like a lean bog. although, did it just start doing it? If it did, and since nothing weather wise around here has changed, I would bet it's probably your reeds.

Take that with a grain of salt, as I am a 4 stroke guy.

[thoryamaha22]

it a YZ 85 2003 it just has a FMF fatty and shorty on it

[DCox]

This may not be the case in your instance, but I had a similar thing happen with an old RM 80 I once owned. Come to find out, I had simply put too much oil in the filter and it was starving for air from half throttle up (bog). I recleaned the filter, added less oil and it ran great.

[Woody_393]

Is it a bog or a sputter?

[thoryamaha22]

kinda both

[Woody_393]

Well, the sputter will cause somewhat of a bog, but is a Rich condition, whereas the bog alone is a lean condition.

Also, chipped or cracked reeds will cause a sputter as well.

Did it just start happening?