BK mod for 1998/1999


3 replies to this topic
  • tammie

Posted February 13, 2005 - 10:06 AM

#1

what is this mod for the 1999 400? searched for that thread but no longer exists on server..........

  • PumpkinHumper

Posted February 13, 2005 - 11:35 AM

#2

I hear that there is 2 ways to do this.

1. Drill and tap the bottom of the acelerator pump and insert a set screw to limit the travel of the pump.

2. The other is to install a locking coller on the pump shaft (brass looking thingy) to limit the travel. You can get these collers at Radio controlled car hobby shops.

Mine is still stock. I was looking at www.powersportspro.com and they have listed diferant acelerator pump diaphrams for our bikes. Never tried to order them though. This is how we were supposed to tune the pump on the older bikes.

Yep I just looked there are 4 diff diaphrams listed for the 400.

5JG-14940-05-00 $16.99
5JG-14940-07-00 $16.99
5JG-14940-08-00 $26.99
5JG-14940-09-00 $26.99

Not sure what one is the stocker though.

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

Posted February 13, 2005 - 12:32 PM

#3

what is this mod for the 1999 400? searched for that thread but no longer exists on server..........


The BK mod wilnot work on the 400's ony the 426 and 450
for the 400 you need the Factory R&D P-38 Lightning

do a search for Factory R&D P-38 Lightning in the 426 section you will learn about it.

Here is a link to the mod
GBmod Explained Thanks Garrett

  • NAFLASH

Posted February 13, 2005 - 07:19 PM

#4

wait a secong isnt there the Taffy mod, it has to do with putting a collar on the accel pump rod i think to shortin the duration.





Related Content

Forums
Photo

Should I buy this bike? help....... by Numsa Hul


Dirt Bike   General Dirt Bike Forums   What bike should I buy?
  • * * * * *
  • 10 replies
Forums
Photo

Is it worth it? (Cam and High compression piston) by macgi77


Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies
Forums
Photo

05 yz450f not fast enough by RedeyeYZ


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  38 replies
Forums
Photo

YZ450FX OR YZ450F by MESSMAKER


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • Hot  30 replies
Forums
Photo

James Stewart back on a YZ450F by YamaLink


Dirt Bike   Special Interest Forums   Pro Racing
  • Hot  47 replies
 
x

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.