Burner, how do you confirm the main,needle,needle clip for a FCR carb??

[RideRaceLive123]

Burned, How do you confirm the main,needle,needle clip settings for a FCR carb? Because I have heard many different ways? Like for the main I have heard that people do a chop test,jet by feel, and a couple other ways. But I just want to know how you do it?

[Wayward Son]

its burned

i use a dynojet dyno and a wideband air/fuel meter for 95% of my testing.

but with out a dyno the following method works as well.

main jet-

assuming the bike already revs out start going leaner on the main jet till the bike wont pull clean/stutterrs/misses or whatever.its pretty obvious when a 4 stroke is lean on the main jet.once you figure out what the point of to lean is go back up 2 sizes mai jet.thats as about as close as you will get with using a wideband a/f meter.

needle straight diameter-

a lean needle straight diameter feels like a "gallop".the rpms wont be steady.rich straight diameter feels like the rear brake is dragging.

needle clip position-

rich feels soft or soggy.lean feels like the kill switch is being pressed.

there alot more to it than that,but thats the general deal.

engine temperature is also a big indicatior of jetting.

problems that occur with more engine heat are rich.problems that get better with engine heat are lean.

most people end up making there own problems by trying to cure problems with "hot set ups" that didnt adress the issue they were having.

also,spark plug color leads many people in circles.

[RideRaceLive123]

sorry for calling you burner..

Have you tried a OBFHN needle? If so, how did you like it?? Because I remember SUnruh(sp) saying he liked it.

Thanks so much...

[Wayward Son]

in a yz250f?yes,ive tested.worked depending on the set up.

the F taper needle is alot of taper.

[RideRaceLive123]

Yes, in my YZ250F.

[Wayward Son]

for what kind of riding?

[RideRaceLive123]

For MX only. Also where I ride the altitude is between 200 to 1000 And the temperature is between 60 and 80.