2000 426 bkmod

2 replies to this topic
  • moorespeed426

Posted March 26, 2002 - 09:46 PM


I did the bk mod to my 2000 and the throttle response is great but I still get the bog off the bottom. I frist tried a 45p and it ran with the screw all of the way, so I tried a42p and the bog was worse., no matter what pilot I use there is still a bog. My bike has a stock pipe, set pump to .3sec, raised needle one clip and started with a 168m and now I am at a 165m, gearing is 13-49.Tomorrow I am going to set everything back to stock and see how bad the bog is, although I really like the aceleration of the bk mod. I may just stay with the mod and go with 13-50or51 gearing to get through the bog zone faster.Any suggestions?

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • Shawn_Mc

Posted March 27, 2002 - 02:33 PM


Dial in the pump timing, I did this with the engine running. Seemed like I got more performance from setting the pump timing than I did with the BK mod itself. I just played with the pump timing until I could wack the throttle wide open w/no bog, just sitting in the garage. Then I rode it, all I gotta say is Holy Cow! Im running a 168 main 45 pilot, with the stock needle 1 notch richer than middle. But I have a performance pipe too. But Im thinkin the bikes are a tad lean stock. good luck

  • Boit

Posted March 27, 2002 - 03:07 PM


My experience was the same as Shawn's. Before the BK mod came along, the only other alternative was a Factory R&D accelerator pump plate. While it improved the problem, I still had to adjust the pump timing to the get the little bog out.

Shawn, did you write a little note to Cycle News about Harley's illegal displacement disqualification and their excuse that it was an "accident" ? It's on the bottom right hand corner page 5 of the March 27 issue.

Related Content


First Hare scramble tips by dhend8

Dirt Bike   General Dirt Bike Forums   General Dirt Bike Discussion
  • Hot  33 replies

100 hrs on 2014 yz450f, shim valves or replace them? by ttr230rider6

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  79 replies

James Stewart back on a YZ450F by YamaLink

Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies

Michigan Motocross Tires by 288yz450

Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • - - - - -
  • 0 reviews

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.