carb issues

[c.a.kustoms]

79 xs1100 special, indy filters, 4-1, no muff

with stock jets, bread tie synch, idle screws adjusted to 4 turns out. bike runs great between 3200 and 5000 rpm, below- no power and boggy, above sounds lean. at idle it will climb up to 2800 rpm like its still lean. highway tested plugs- looked a little rich ( slight carbon) and at a steady speed (around 50 mph) it started surging and getting boggy.

with 152.5 mains and 47.5 pilots (as recomended in the jetting chart on this site ) no main idle adjustment, slow coming off throttle, acts and sounds like it's drowning when in gear.

i've read every thread i could find on carb problems, tried everything i could think of or read, and i still can't get it right.
it's not bad to ride aroun town when you can keep it between 3200 and 5000 rpm, but there's no way this thing will see any highway trips like this.

PLEASE HELP ME.

[c.a.kustoms]

oops

forgot to mention that i have checked for air leaks and the slides are operating properly

[randy]

with 152.5 mains and 47.5 pilots (as recomended in the jetting chart on this site )

IIRC, no jetting suggestions here that don't include a muffler of some sort. Try putting a muffler on it.

[TopCatGr58]

Hey Randy,
I just reviewed the jetting guide, and there IS a suggestion for Open Headers, but I think Kustoms has gone too far, too rich, cause I think he combined the 3 sizes for Indy filters, the 2 jet sizes for Open Headers AND the 2 jet sizes for 4-1 pipes, but I think it's either/or situation with regards to the exhaust type! Both 4-1 pipes or Open Headers remove much of the restriction of outflow which contributes to a leaner condition vs. stock.

So...try cutting back a couple of jet sizes in the mains. 3 for Indy filters, and 2 for pipes=5, but -1 for combo results in 4, so should be 147.5 for mains. As for the pilots, I think with 2 sizes up and 4 turns out, you're sucking in so much fuel at idle, I think that's why it's creeping up, not because it's lean!

You could try putting back in the OEM pilots, and keeping the turns 4 out, or put in 45's, and then start at stock 1&1/2 out, and adjust per response.
HTH? T.C.

[c.a.kustoms]

i did not realize

guess i never thought about the no muff- 4 into 1 combo like that. thanks for the idea, i'll give it a try.

on another note- my brother-in-law has the same bike except that we only cut off the muffs and added turn-outs to the stock pipes. after cleaning and synching the carbs it runs awsome with the idle needles out 3 turns. i haven't rode a bike for awhile that will drift sideways with a quick snap of the throttle in first gear.
what a rush !

[dragxs11]

Welcome c.a.,
I'm assuming indy filters are like cone filters here......
Just finished bringing back a xs650 and put cone filters on it. Had to lean out the mains and drop the needles. For some reason I don't fully understand, the cone filters make them richer. I'm not the first person to say this. I suggest you get the idle mixture good first..... get it warm, then put fresh plugs in it and let it idle for 10 minutes. Once you get good color you know that your pilot settings are no longer to be disturbed. I'm sure you get it. It's a pain in the A## process, especially with 4 carbs. Thats why a fuel injected bike starts to appeal to me every time I go through this. Also, the stock pilots that originally were in the carbs may be needed, and I'm not talking about new ones with the same #. Don't ask me how I know.

[dragxs11]

time saver

If you have the stock jets in, and you start with any given pilot screw setpoint, you can adjust them a half turn at a time either way while idling to see if your rpm changes. Obviously, if you turn them all in a half turn, and you get another 200rpm, it likes less fuel. Just a way to get in the ball park. Maybe you already know all this.... I'll shut up now.

[fedexguy]

hey c.a.

I basically have the same setup and bike you do with the exception of no muffler and i to had the same problem where it seemed to gurgle at low rpm's ! what worked for me and i don't know if it is right but like i said it worked for me was i raised the floats out of spec to almost 1 1/4 inches and dropped down to 142.5 mains with 45 pilots at 1 turn out ,, i tried every jet combination under the sun and nothing seemed to get rid of the "gurgle" at low rpm's until i raised the floats once done with that it the "gurgle" was gone and now the bike runs great !!! I wouldn't say this is the correct answer but maybe just something to give a try and see if it works for you also and also with 147 mains your gas mileage is going to bring you to the gas station often as u get not so great mpg i only got maybe 40-50 miles to a tankful with that configuration just something else to think about

[planedick]

Same setup, almost

I have a '79 standard with Jardine 4 into 2, carbs stock jets and I found that 1 1/4 turns on idle jets work best. I can have a good reliable idle around 500 rpm. I had similar problems with fast idle and spent a long time with spark advance issues and other things. It would idle fine until I reved it up then it wouldn't come back down except with a little load. I found the real issue was balancing the carbs. Properly balanced everything works fine with idle jets 1 1/4 to 1 1/2 turns open gets me very good idle as low as 200 rpm.

[Winterhawk]

Make sure that someone didn't put a K+L kit in it with the pilot jets not being sized to a true 45 or so. They drilled some of the holes in their jets wrong and makes it to rich at idle.