Hot4Teacher

Member
Apr 21, 2002
87
0
I have a '99 yz400f. I hear alot of prople doing a BK mod on the newer thumpers. I was told that the mod can't be done on the 99 because of the different carb. Is this true? or is it just a little different technique on the older yz's? Any help would be greatly appreciated. Thanks.
 

endosports

Member
Jan 10, 2002
494
0
Different carb all together... I haven't looked at it closely on the 400 but i believe that it is not possible.
I have done this to my 01 426, but it is a different carb all together. Can't tell you how much this mod has helped me out.
 

Shawn Mc

Member
Apr 8, 2002
152
0
You can acheive the same thing with a p-38. Its an acclerator pump housing that replaces the stock one. I wish I could remember the Manufacturer. You can get it at MR.X i think.
 

Hick

Member
Aug 15, 2000
224
0
You can buy an RC Wheel Collar and install it on the pump actuating rod for the same effect.

Click HERE to get the wheel collar, apparently the 3/32" collar fits best. The idea is the collar fits on the rod, acting as a stop to limit the pump stroke (ala infamous BK mod). Cheaper than the P-38 and infinitely adjustable.

I have not tried this myself, but plan on using my friends 520 EXC as a guinea pig. At any rate a few guys at Thumpertalk have tried this with some success.

Hope this helps.
 
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