Help Please. I just picked up a 1998 Yamaha Warrior it s a. 010 over bore

Help Please! I just picked up a 1998 Yamaha Warrior it's a .010 over bore (what I was told) has stock pipe no baffle, and open air box with a dual stage filter. It lags/bogs super bad mid throttle but not any other time what could be the problem? The guy said he changed the jets a few times couldn't get it right. I know it's a carb issue but what could cause this?

10 comments
  • raise the midrange needle...

  • .10 over dont require jets. sounds like it needs put back to oem. and it be fine. like to know the symptoms ? cause it could be out of time. and he assumed and you assume its carb.,

  • check the accelrator pump in the carb mine did that had to replace it

  • Yep..check accelerator pump also...they get stuck down

  • It idles fine and everything it just bogs out when you punch it. But if you feather the throttle it doesn't do it as bad.

  • Mine will almost die too when i punch it. I think its the accelerator pump. I think there is a mod for that. I know there is a zip tie mod on the yfz450.

  • Warrior with radiator? Is it water cooled?

  • I think is a oil radiator. Wolverine mod

  • There is a mod for the accelerator pump. It's a pen spring. I'm having the same problem with my 98. Never thought to adjust the needle. Mines far from stock. It's .40 over, oversize kibble white valves& springs, stage 2 hot cam,and fmf slip on. I was aiming more toward the parking brake delete that I thought wasn't fully finished but I couldn't come up with any better results.

  • yamaha carb bog and runs like shit means carb is dirty. it needs cleaned really well. and make sure all jets are clean. and if he tried to jet it and its not right cause the valves havent had work then its leaning or riching out. but normally that is the old fashioned sign of dirty carb. clean tank and pet cock too.