Jump to content
Sign in to follow this  

My 01 YZ426F and jetting

Recommended Posts

Yes, I already did a search and I can't really find anything solid to go off of.

Have a 01 yz426f with a fmf powercore 4, I run a 50/50 mix of 101 octane race gas and 91 pump gas. The bike has no air box lid and I throw a new plug and oil in regularlly. The only reason I run that fuel mix is because that is what the bike likes most, I tried all different fuels/mixes and that was best. Carb settings are stock to my knowledge and I figured I would ask the pro's here before I started messin around with it.

The bike runs good, can be difficult to start sometime and I do know how to start it. The problem I am trying to fix is that at idle when I give it a twist it seems to just fall flat on its face. I don't crack it all the way, just maybe 1/4 give or take and it just dies. This really becomes a problem when we are trail ridding, cause I am constantly on and off the throttle. It won't do it all the time, and is even worse in neutral standing still. After I am going and start cookin through the gears it runs like all hell, but I am not always "flying".

I haven't done anyting to the wires (grey wire mod) or any other quick mods.

elevation +/- 575 Lockport, Illinois

Any and all ideas, Thanks

Share this post


Link to post
Share on other sites

I would say do a search for the GB mod and get the accelerator pump dialed in, that will probably help a bunch. How about the fuel screw - have you played with it lately? Sometimes a little adjusting on it will help your type of problem. You may even need to clean the carb - if the pilot jet is plugged it can make for hard starting and bad off-idle response.

Share this post


Link to post
Share on other sites

Hey, good idea, Duhhhhh. Clean the carb. Now why didn't i think of that. The bike is always clean, but i just forgot to clean the inside!!!

Share this post


Link to post
Share on other sites

Boysen accelerator pump cover? If your problem is crack throttle bogging, a lot of people like the boysen cover. I have it. They (Boysen) have a money back guarantee that they really mean. My problem was stalling. I would stall it hot in the middle of a fast run with the boys, never cold. It would re-light and idle fine, then when I cracked the throttle to take off again, it would stall again. This is an accelerator pump problem. Good luck.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×