carb problems

[dragginit93]

ok heres the deal i got my bike runing and i have bs34 on the bike and one side is runing colder than the other.i tried syncing the carbs and one side of the tool u could see a mist in he tube on the carb that seemed to runing good and on the side that was runing colder u coulding see the mist in the tube.I too the bowl off the cold carb and the pilot jet was clogged would this make that side run colder?

 

[xsjohn]

These run hotter on the right and the BS34 just added to the problem being EPA lean......ruins the whole thing...good carbs if done right but if left will trash the whole thing.....what woud I know...and the TCI is a bit advanced which makes it cranky unless you rev it..on top of all the leaness...easily fixed but no one ever does...ah well..........nice to fix all that before it happens ........if not it's repairs........

xsjohn

 

[dragginit93]

ok heres some more info the carbs have been rebiult and im running a 142.5 main and a 45 pilot with drag pipes, and pamco ignition, and v stacks.The motors been rebiult with a .25 over kit.the left side(side that was runing cloder than the other side)wasnt cold it was warm but wasnt smokin hot like the right side.Do u think the cloged pilot was the problem?

 

[xsjohn]

No............the left just runs colder than the right....and the jet needles have to be handled differently...as I well know..........after all these years of preaching .........and a 142.5 will just wash the whole thing out fast with those log needles provided by the epa......lots of fuel on the high end (142.5) and about none where you are at most of the time.............

xsjohn

 

[dragginit93]

i have the adjustable jet needles from mikes xs and the needle jets that go with them

 

[Sundie]

gurgh. I just had this "discussion" with someone who's running 145's. way. too. rich. "i'm fouling plugs" Put your jets back to stock and work from there. "i hesitate and die above 4500 rpm" <repeat> "it's running like crap" <repeat>


With wide open intake/exhaust, start 2 steps up (137.5 in this case) and go from there *with* John's adjustable needles and your adjustable needles all the way down (clip at top) on a BS34.

Then do a WOT test in 2nd from 3500. if you don't die before redline, move up a jet size. Repeat until you start choking at redline, then move back a main jet size. You can confirm the jet's too big by letting off the throttle a bit when it starts hesitating. This will lean the mixture out to a burnable ratio, so your engine will run, and can maintain RPM's and speed.

After you've got your main settled, start moving the needle up. This is more of a seat of the pants art (unless you have a dyno handy) to feel if there are flat spots (leanness) or hesitation (richness) in transition from 3500 -> redline. Move the needle up a notch, see if it feels better. Move it up another notch, see how it feels. If you think that it felt better down a notch, do that.

Then comes the pilot jet.go back to your stock +1 (45 in this case)and do a 1/2 throttle test from 2000 -> 4500 or so. See how it feels. Repeat as you did setting the needle, going up a jet size, see how it feels, back it off if the smaller felt better.

CV carbs are *very* easy to run rich, since the slide only comes up on vacuum, and the vacuum only makes them go all the way up when you're at WOT making it pull hard.

Temperatures go down with fuel richness as well.