2012 YFZ 450 w/carb

[RockinRob]

Hey HMF guys, alot of us who have bought the new 2012 YFZ 450 with the new BSR 42mm carb are having problems finding any jetting resources for our machines. Can you guys help us out with some slip on, and full exhaust settings. It would be VERY appreciated. Looking at the Comp series slip myself.

[Mike/HMF]

Check it out Rob.

2012: Slip on & Full: No Airbox Lid 165 Main Jet. Move the washer to the bottom of the needle.

2012: Slip on & Full:Air Box Lid On Stock Main Jet. Move the washer to the bottom of the needle.

This is what worked best for us on our test quad. This carb is a bit more forgiving than the FCRs on the earlier models. The throttle response isn't as quick as the FCR, but the "throttle stab bog" is nearly non-existent.

[RockinRob]

Thanks alot for the info Mike. What do you mean by the BSR is more forgiving?

[Mike/HMF]

The FCR carbs are notorious for bogging when you stab the throttle. Your BSR won't cause the engine to bog as much if at all. Also woods riders will probably like this carb better because its not as hard on your arms.

[jtwtre]

I jetted the carb on my bike did what hmf sugested droped the washer to the bottom ran so bad!!! after messing with the air fuel screw so much never could get it so i put it back to stock runs way better but now my air fuel screw leaks??? not sure y i pulled out out on aceident put back in leaks now but i have been messing with it to get the poping to stop when letting off the throttle any sugestions

[Mike/HMF]

When you test rode with washer on the bottom did you have the air box lid off? What was the thickness of the washer you moved?

Fuel screw has an O-Ring that may have been torn in the process of removing and installing. Should be able to get a Viton O ring replacement locally.

[jtwtre]

Originally Posted by Mike/HMF

The FCR carbs are notorious for bogging when you stab the throttle. Your BSR won't cause the engine to bog as much if at all. Also woods riders will probably like this carb better because its not as hard on your arms.

no i moved the thick washer and no i dont think i tore the o ring cause i put it back stock and runs great now? not sure y it was runnig that way.But next time i will just take it in probly cause the new carb is nobody really nows any thing about it there are no forums.

[Mike/HMF]

There should also be a thinner washer. This is the one we moved.

[jtwtre]

Originally Posted by Mike/HMF

The FCR carbs are notorious for bogging when you stab the throttle. Your BSR won't cause the engine to bog as much if at all. Also woods riders will probably like this carb better because its not as hard on your arms.

Ok i will have to try to move that one.

[2012yfzfour50]

I too have the 2012 yfz carb model and just purchased the hmf comp series and the basic jet kit w/ the uni filter I live in Florida and its hot and humid 80% of the year what jets can I plan on running when the pipe gets here? Any help would be greatly appreciated