BK Mod

I just bought a used 2000 YZ426 and love it. I haven't had any problems with it and was wondering if the BK Mod was for me or not. The guy I bought it from was up on his stuff, so he might have already done it. How do I check and if it doesn't have the mod where do I get the parts? Is there anything else you guys suggest?

I ride up in the hills on trails mostly, but want to get into a little MX racing eventually.


Welcome aboard! I also have a 2000 that I've done the mod to. It's really easy to check, simply look at the throttle cable housing, if there is screw sticking out of the back of it (roughly pointed at the shock), then you've got the mod. If the cover is complete and hasn't been modified to allow a screw to stick out, you probably don't have it. If you don't, check out Motoman393's web site here. There's plenty of info on how to do it.

The mod is designed to get rid of a bog at low RPM's when you open the throttle quickly. The stock accelerator pump squirts too much fuel in and creates the bog. The mod shortens the squirt duration and reduces or eliminates the bog.

I had the bog and since I've done it, well, it's started raining and I haven't ridden much, but with limited data I would say it's pretty much gone now.

The BK mod was an excellent fix for the "00 model as mentioned above. If you noticed a little hitch....or slight hesitation when you whack the throttle open at low and low-mid RPM's, your bike might benefit from this mod. My '00 had a very annoying hesitation somewhere around 3500 RPM if I twisted the throttle open suddenly. I solved this problem by means other than the BK mod.

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