started adjusting pilots, now wont stay running

I just rebuilt BS38 carbs on my 750 twin, and man what a difference. Runs real smooth now (it did anyway) except it idled ~2500, pilot screws turned out 1 1/2 to 2 turns. I needed new throttle cables, so I rode it for a few days with the fast idle. Now I replaced the cables last night and went for a ride this morning to warm it up before adjusting the pilots and idle. It started with one kick with the choke full on, and ran really good. When I started to make adjustments I was doing OK, pilots about 2 turns out, idling about 1050-1100 rpm - but when I twist the throttle it would hesitate and then die. Had to be real easy on the throttle till about 2000 rpm, then it would be fine. Then all of a sudden it doesn't want to start and run for more than a few seconds. Even if I set the idle higher, pilots about 2 turns out and choke on, or any combination of these, it is not starting and staying running. It was going so well... Now I did check spark, and all is well there. This bike has stock airbox, stock carbs, 2-2 head pipes from MAC exhaust and 2 mufflers from Harley Sportster, no crossover. Electronic pickup from kz440, GM HEI igniter per Lou D ( www.geocities.com/loudgpz/GPZgmHEImod.html ), Harley Screamin Eagle coil and the relay coil power mod. Everything was goig so well, till this carb adjusting session. Suggestions anyone?

Electronic pickup from kz440, GM HEI igniter per Lou D ( www.geocities.com/loudgpz/GPZgmHEImod.html ),

Way to go!

Might have developed an unrelated problem while you were messing with the pilots, like maybe a fuel flow problem. Checked the petcock screen, and the screens on the petcock intake inside the tank?

No, I haven't checked the petcock screens yet. I did notice that the fuel line to the right side carb was not full of fuel (fuel was up in the line about an inch above the carb connection), but this thing has been running all summer. I know that it could be causing a problem, but how likely is it that it just now is a problem when it has been working well? I guess that I will check the petcock... I should put an inline filter in too. There was a very, very small amount of extremely fine particles in the fuel bowl of one carb when I took them apart.

The electronic ignition has been working without any problems for a couple of years or so. You may remember a while ago that I had a Mallory Hifire system that developed issues (turned out to be broken component leads to circuit board, caused by vibration). It was the Lou D HEI setup that I replaced the Mallory system with. The only thing I miss from the Mallory is a rev limit. Before this issue, my bike would accelerate hard from 4k rpm to well into redline and still want to go for more, even with the messed up carbs. I have been meaning to go to a single carb or fuel injection, but I cant have the bike down for more than a weekend, as it is needed to get to work while my wife needs my car because her van died. I finally found somewhere with carb kits available and decided I can do that quickly. If I get this starting/idling fixed and it runs as sweet as it did the last couple of days, I may not switch to a single carb. I will do the FI sometime though. I have to have something different than everyone else (besides just a sweet running 30 year old bike)!

I know that it could be causing a problem, but how likely is it that it just now is a problem when it has been working well?

A new problem is as likely to pop up now as it is at any other time

Had my bike running great, left here to go to work, made it a mile down the road and had to push it back home. Petcock screen chose that moment to plug up.

Stuff happens when it happens, no rhyme or reason, no connection to anything else.

Lou developed the igniter to solve a problem for someone, no charge, and then posted it for anyone to use after testing it on his own bike. I really respect him, and I don't say that often.
He's a young guy, and he's going places.

securitygeek wrote:

It started with one kick with the choke full on, and ran really good. When I started to make adjustments I was doing OK, pilots about 2 turns out, idling about 1050-1100 rpm - but when I twist the throttle it would hesitate and then die. Had to be real easy on the throttle till about 2000 rpm, then it would be fine.

It's sounds like it's starving for fuel. Check for a plugged up screen or filter, also could be sticking float. You need to check and adjust (if needed) the fuel levels in the bowls.

securitygeek wrote:

Had to be real easy on the throttle till about 2000 rpm, then it would be fine.

That makes me wonder if you have crud in a pilot jet.

Carb bowls are good. Petcock screen was really plugged up. Lots of flakey junk from the tank, but the screen kept it all from getting to the carbs. It now has been cleaned out and inline filters also installed. Later today (Monday, Labor day) I will get to finish making the carb adjustments, and hopefully all will be well. Thanks guys for the suggestions on what to look at. It helped a lot. this place is the best!

Everyone have a great Labor Day. Those of you in Gustav's path, take care. My prayers are with you all.

The final carb adjustments are done. It now runs VERY well. I am enjoying the bike even more now. It will take a little getting used to coming to a stop and just let it idle on it's own. Before if it started running only 1k rpm it was going to die. Now I have to remember that it is ok, I won't be stuck at an intersection as cars line up behind me, waiting for me to get started again!:ohmy:

Milage is up some too, mid 40's instead of upper 30's, and I wasn't riding economically:laugh:

All in all, a really nice change...