New Pipe, new problems

[threatready]

I have an fmf header and pipe installed on my yz 250f and at full throttle it was not getting enough fuel so i moved the needle clip position down one which solved the top end. but if I am going slow and open the throttle all the way the machine will bog down and even stall if it is held open. same thing if I where to climb a sleep hill if i juice it the machine will bog down.
Any suggestions would be great. Maybe a new accelerator pump?

 

[lucm]

Although I don't know much about the yz 250, the first 1/4 throttle is set by your air/fuel mixture screw(s) so it sounds to me like you need to set those.

 

[whopper809]

Your jets are lean. You need to jet up asap or you could cause some piston damage. The needle only adjusts mid throttle performance and your jets full throttle performance. Jet up a size maybe two. With the install of your exhaust your bike will need more fuel to compinsate for the faster exhaust air flow.

 

[threatready]

Roger, thanks I will give it a try.

 

[crazy_wheeler]

Threatready make sure to put your needle back to the stock position as well and then increase jet sizes one size at a time. Check your plug to make sure your not running to lean

 

[threatready]

I did just that. I went up two sizes then had to put the needle clip back . Problem solved. thanks guys saved me alot of time.

 

[cey800]

This is the best part of this site. Read posts about mechanical issuses and hearing members help others with their problems. Great work guys/gals!

 

[crazy_wheeler]

Threatready glad to hear we were of help and now you can rip on 'er good this weekend.