BK Mod "again"

I was just wondering if anyone has done the BK mod here in Colorado on a 2000 or 2001 YZF426. I would be interested to talk with someone who has. What type of jetting and needle setting works best at this altitude after the mod is done? I am in the northern colorado area. I ride a lot at Berthoud roughly 5200feet. Any help would be great. Thanks John

I have done the BK mod to my 01 YZ426. I live in Lyons and ride the bike mostly at Berthoud. I bought extra parts for my WR250F but it didn't need the mod, the squirt was already 0.3 seconds. I can give you my parts (but not the tap) and help you out if you want.

Jetting:

168 main at 30F

165 main at 45F

162 main at 60F

Needle by feel (I would have to look)

42 pilot, 40 in the summer

FS by decel popping (get a Kouba, had one for a year and its worth it.

I've done the Mod. and I live in Tucson, Az. elevation, 2400 ft. Duration is about .3 seconds, timing just clears the slide. I still had the hesitation just off idle, rejetted to 45 pilot and 165 main and run VP C-12. The hesitation is gone and the bike pulls clean and strong all through the rev range.

Good luck, I hope this helps....Chris

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now