carb jetting

[GARTHXS]

so I put on the 4/1 exhaust and put in bigger main jets and pilot jets, the main jets seem to work but what size pilots should I use

[GARTHXS]

size

the mains are 142.5 and I tried the 47.5 and 50 for pilots but they are not working.
It wont idle , and it runs like crap until about 3800 rpm then winds up real nice after 4000rpm

[jjwaller]

Have you synced the carbs?
Still, it sounds like you have other carb issues. Has the bike beem sitting up for a while? Sounds like you have some plugged or restricted low speed circuits.
Possibly, try turning out the IMS screws
to 2 or 2 1/2 turns out. Maybe.
Still the 47 or 50 pilots should be plenty.
Try a plug chop at sub 4000 RPM with new plugs for additional info.

[GARTHXS]

yeah

the carbs are synced but I found out my petcocks were both free flowing on all settings I guess Ill clean the carbs again

[GARTHXS]

oh yeah

I switched to my other tank with working petcocks also

[GARTHXS]

ims

??? and what do you mean by chop

[GARTHXS]

plug chop

??

[jjwaller]

Plug Chop

Run at desired RPM for desired mixture, and then hit kill switch while pulling in clutch lever, Come to a stop and check plug condition. Why I say use new plugs for the most accurate view. Should tell you if you are running lean or rich.
HTH.

John

[Guy_b_g]

He means run it under load at 4000rpm or less at normal operation temperature, then hit the kill switch and coast to a stop (clutch in)...like what you hear at the end of a NASCAR qualifying run when they kill the ignition and coast into the garage area to see how the plugs read. Sub 4000 rpm because that's where to problem is...just coast to a stop and pull the plugs to check for rich/lean condition.

[Guy_b_g]

oops..too late!

[jjwaller]

Thanks Guy,
That sounded better than mine

[dbeardslee]

You put a 4/1 on - did you do anything on the other side of the carbs. Might try a freer flowing air filter and drilling the box so that you are addressing both sides of the equation. Also, pilots at 47.5 are two sizes too big for just a 4/1.

[jjwaller]

Originally posted by dbeardslee
You put a 4/1 on - did you do anything on the other side of the carbs. Might try a freer flowing air filter and drilling the box so that you are addressing both sides of the equation. Also, pilots at 47.5 are two sizes too big for just a 4/1.

45's are stock on the 78's, so 47.5 (1 size up) is reasonable for a 4-1. But probably not necessary.
Drilling out the airbox or otherwise increasing intake flow will make it leaner and leaner. Sounds like thats the problem to begin with.

[GARTHXS]

plug chop

ah I understand now, will do btw I have pod filters I think Im going to pull the pilots and clean and see if that will help

[GARTHXS]

also

the pipe I m running is a bassani 4/1 which is a litlle better than a straight pipe