Rich or Lean???

[Yamaha72]

I just put my Yoshi on my raptor and now every time I pin the throttle and let off it shots a 1ft flame out? no tell me is it running rich or lean? I am guessing it is Lean!!!!!!!! but hope not.

[dynodon]

Did you re-jet the carb for the pipe?

[klutchbuster400]

lean.

think of it for a minute. fire requires oxygen to ignite. the more oxygen(lean)the more flame. so yes u r runnning lean. remember more out(pipe) requires more in(jet kit). in my opinion its always better to run rich then lean. it will run cooler rich and hotter lean.

[Toomey]

Either buy a jet kit, or just go on some Raptor forums, www.bluetraxx.com would work great, and see what the common jetting is for the mods you've done, and go from there.  It'll have more power when you've got it jetted better.

[Yamaha72]

the only thing is that it isn't the stock carb...... it is a Edlebrock. My friend races dirtbikes and is sponsored by KTM and his dad is his mechanic so im supposed to get together with him and his dad on sunday to tune it.................. BUT I WANT TO RIDE!!!!!!!!! Oh well i'll have to wait. Thanks for the info.

[RaptItUp]

Pull your plug after a ride that varies in engine speed (not a lot of idiling or WFO).   The plug should be a medium gray ash color.   White, yellow or brown would be on the lean side, black and carboned up would be too rich.   

Hope that helps

[Mars]

A leak at the head pipe will also cause a big back fire off throttle.

[535banshee]

mars your are the only one that got it. a head pipe with a leak will cause your problem. by the way brown is not lean.its just right. when you let off the gas the exhaust will suck in air at the leak and cause a lean condition

[Yamaha72]

MARS YOU ARE THE MAN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

That was the problem.!!!!!!!!!!!