[Tobycakes]

Hello out there! I was curious to see if anyone out there has found a larger carb bigger than a 38mm that fit their bike well and worked better with their performance upgrades like exhaust and big bore? Trying to find the best route to go with the original gas tank that hangs over the top of the original 38mm.

 

[Here 2 help]

A 40mm FCR carb from a CRF450 will work

 

[Tobycakes]

All right what goes in to setting them up? Just looked at them online and saw a electrical pigtail hanging out of it. What do you do with that pigtail?

 

[Here 2 help]

That a throttle position sensor for the 450 - 400 does use it - just tape it up, clip the wires or just let it dangle - it has to stay on the carb to keep dirt out of the operator.

Setting them up is just like every other carb - set the idle first, then ride it for 15 to 20 minutes to get fully warm and make the final adjustment to the idle - while riding it, try running at steady throttle in 3 or 4th gear (1/4 throttle, 1/2 throttle a nd 3/4 throttle to sense if it's too lean (surges) or too rich (blubbers like the choke is on) and adjust the slide needle for a clean mid-range - finally get it out where you can open it up in top gear - when it's topped out, does it surge or blubber? Change the main jet to correct the air to fuel ratio for clean running wide open. Whether lean or rich change jets in two size increments until you find the sweet spot and fine tune by going up or down one size from there.