Just did BK mod...WOW!

i finally got around to doing this BK mod deal after almost 8 months of putting it off.My bike was a dog out of the corners with 14/50 gearing.on top of that i was getting beat out of the turns by some 2 smokes!(cant have that).All i can say is if you havent done it,your missing out.i couldnt believe the difference it made.all along i would read about it but didnt want to bother because i didnt think i needed it WRONG.i actually fell in love with my bike all over again,plus this mod was FREE,best of all.I have a load of snap of the bottom now,it feels like a new bike,its worth your time easily(about an hour :thumbsup:for me)

What is this mod, and how is it free? I like free!

Here's the link to the BK MOD from the Motoman393 web site,


I have an '01 426 that was having "issues" with bottom end richness. It has the stock pipe with the ProMoto end cap, spark arrestor and "Mr. Potato Head" quiet core plug. Hence the rich bottom end condition. I did a modified version of the BK mod that a friend showed me from a magazine where you turn the "pump timing screw" clockwise one half turn. I went 3/4 of a turn actually. What this does is shorten the time that the system injects fuel into the carb when you even so much as touch the throttle, like when starting the bike.

I also disconnected the lite blue wire in the harness under the tank. Motoman has a page on this also. And last but not least, I dropped the needle one notch from the stock position. This made a huge difference in how my bike not only starts but also its throttle response off idle. Oh yeah, I put a longer fuel adjustment screw in the bike for ease of adjustment. Definitely the "hot prop" I would add.

Hope this helps!

Bob :thumbsup:

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