I am selling my bike and recently have been riding a buddies yz 426. The other day we took it to Performace Factory who did this carb mod. Before there was a hiccup or hesitation on the bottem end of the bike, and this mod compelety cured this. I couldn't believe how much of a difference it made. Anyhow, just thought you yz/wr 4 stroke owners might want to know this. It's a really inexpensive mod, if you want to know contact information e-mail me at blackhawk468@hotmail.com
Of course it's OK! :) I believe the mod that was performed is known as the "BK Mod". (BK being the initals of Tim Ferry's mechanic, who invented the mod, I think) It is a very quick and effective mod.
If you get a 4-stroke, you're gonna have to change your sig line from "BRAAAAAP!" to "BUURRRRRP!" :D
Actually, in respect to the guy that REALLY invented it, BRIAN KINNEY, I'll set the record straight. He deserves a lot of credit. Him and who ever spilled the beans on the gray wire!!
Actually, the P-38 lightning was the first to limit the AP stroke. The BK mod is for the later model FCR's......... Post P-38. The modification limits the AP stroke (less raw fuel into the motor) which will NOT create a rich condition when the throttle opened.
Well Actually, The mod I'm talking about has nothing to do with the P-38 or the AP stroke. I don't know how to do it and I can't provide pictures. All I know is that it works, and he did it on Jeff Gibsons and Lance Hollister's bike. It was done on Tim Ferry's bike as well, and Yamaha took the bike apart and could not figure out what was done to it and they won't tell me damnit.
I don't know how the guy does the mod or what he does, so I can't provide pictures because I don't know what he did to it. I was just informing everyone that there is another mod out there that can be done its not the BK mod or the P-38 one, and I thought it was more effective.
I'm selling the RM because I'm trying to get money up to get a new bike being the serious motocrosser I am. ;) I'm goin Blue!!!! :)
Go for the 250 2-stroke, more power! AR AR ARH :p Your lucky your down south.... lotsa room to practice. You probably have a big track near ya too. Where I am up North there are no nearby tracks I know of, limited riding areas.....hey does anyone know any motocross tracks located in Virginia or North Carolina?