New '01 YZ426 - BMP spark arrestor jetting?

I picked up my new 01' yz yesterday. I just want to thank all the people on the forum for all of the set up tips.

I've been busy loctiting, greasing, and oiling stuff...

Starts 1-2 kick when cold (so far), same with hot start.

Since I would like to ride in a nearby forest, I've heard that the BMP spark arrestor is a reasonable deal ($130 or so).

For those who've installed this, did you have to adjust the jetting substantially?


Oops - didn't know I could just use the "search" function to see what else had been written about this already.

Looks like the topic is covered well enough already.

Sorry for the extra posts...

I just installed my BMP spark arrestor a week ago. It's great! I used the standard 8 plates that come with it. Theres still plenty of power left over, and its slightly less obnoxious on the decibel level. I did'nt have to re-jet at all. I did have to adjust my low-speed mixture (pilot), 1/4 turn in . Also, the model that they are shipping now does NOT fit exactly without modifications. You will either have to bore out the new end cap, or can take a dremel tool and cut off about 7/16" off the end of the baffle, what I did. I had heard that this was the case and asked them about it before I ordered it, they said it would fit without ANY modifications. I called them after I found it was not an exact fit and they mentioned that from now on they will bore out the end caps before they ship them out. All in all its a great product!

I also just installed a BMP on my bike and really like it. I didn't have to adjust anything (I had a FMF Power Core 4 on it before) and it runs great. Mine only came with 6 discs so I ordered 6 more and wound up only installing 5 of those (11 total) because the bolts weren't long enough for 12 and the exhaust guard. I too had to cut off 13mm from the inner exhaust to get the end cap on. I also recommend pulling out the excess the packing before you try to stuff the new end cap in. Good luck...


99 YZ400

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