BK Mod on 2002 426

3 replies to this topic
  • guidster

Posted May 24, 2002 - 09:46 PM


I could not stand it any longer. I was told many different things about whether or not I needed to do the mod on my '02. Well, last night I decided I would time the squirt and use it as a basis for deciding if I were going to or not. The pump squirted for a full 2 seconds, although the timing seems ok as it did not hit the side (just missed it).

Anyway, hopefully by the end of the weekend I will have some happy results of the effort and a definitive answer on the worth of the procedure on a '02.

Also, thanks to Motoman for a great web site with pictures etc. for the procedure and the pilot valve mod.

  • kfrosty

Posted May 24, 2002 - 10:34 AM



I posted on this a while back. Probably back in Sept. I found that it made no difference and I could never get my bike to run half as good after doing. (I'm sure you can but I just got tired of fooling with it.)

Also, for all those contemplating this if your bike is already running good, here's the text of the email I received from Brian himself.

Hi there. I have been reading your posts on thumper talk and am sorry to hear you didn't have good luck with the carb mod I posted. I just wanted you to know that the modificaton isn't needed for an 02 426 because they carburate well already. The only reason I would do this to a new bike is to add adjustability to the carb. After all thats all it ever was intended to do in the first place. There has been an overwelming response to my original post but it was not intended to be a cure for all ills. I am happy to hear you bike rips in it's stock form and by all means if it ain't broke don't fix it! But if you just simply remove the adjusting screw the carb wil be back to stock.

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  • Sparky_So_Cal

Posted May 24, 2002 - 12:37 PM


Completed BK mod 2 weeks ago w/an 02 and very happy w/ the results so far. I have ridden the bike once at an unfamailiar track and that day i was having some inflamation of an old wrist injury, but the bike was pulling hard. Can't say as to how much improvement, but it DID NOT get worse. Like I have read here on TT, w/ an 02 it is hit and miss. I primarily did it for peice of mind. And now I have it. Orginal squirt was 1.7 sec and now down to .3 sec

  • guidster

Posted May 29, 2002 - 07:02 AM


I think that the mod is worth doing, but I have more work to do. I cut the stock squirt down from a full 2 seconds to 1 and adjusted the fuel valve. Here are the results that I found:

1. Before COMPLETELY warmed up, the part throttle response was awesome, but a pronounced dead spot was evident when idle to WOT twists were applied. After warmup, the problem subsided and disappeared.

2. The response was much crisper and immediate. To compare, I rode a friends stock bike. Likewise he rode mine and felt the same.

3. The bike seemed much less apt to stall as a result of rapid throttle application. In my opinion, this in and of itself makes the mod worth the effort.

Given the simplicity of the mod and the ability to completely "fall back" to the stock config, I would encourage anyone with a 2002 to give it a shot.

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