I think you just confirmed my next question. The screw/jet under the rubber plug and the one next to it would not budge. Tried to unscrew them but frozen shut. BUT after taking the carb apart for the third time I got it to run for about 3 minutes. Then I started messing with the idle screw (big screw w/ spring above throttle cable?) and it quit. The bike wouldn't start again and I was done. Man when they kick back it's like a mule!!! So I think I need a carb rebuild but that way out of my league. Any suggestions?

 

also...I'm not seeing ( I don't think) the squirt of fuel in the carb when the throttle is open.

 

I probably looked right past it. I do that sometimes. What kind of carb do you have?
If it's a bendix, The squirt should occur as you are twisting the throttle. Picture taking a plunger to the bottom of a bucket. The bucket has a hole with a hose in it. The hose goes out the bottom of the bucket and into a tube(the venturi of your carb). The plunger is directly over the hole. You push down the plunger( twist the throttle) and the fuel is pushed out of the bottom of the bucket, through the hose and into the tube. The quicker you twist , the more force that the squirt has.

Also, if it's a Bendix carb, the suggested idle mixture starting point was WAY to rich for my bike. I ran it in 'til it contacted the seat lightly, from where it was running good, and counted turns for future reference. It was about 3/4 of a turn. The manual suggested 1 1/2 .

 

I just finished taking my carb apart for an overflow problem. It first happened about a month ago while I was filling up at the gas station, right after putting a different gas tank on the bike. Looked down and something was running out under the bike. First I thought it was trans oil (had that oh no! feeling), but after smelling it, I knew it was gas. Turned the petcock off, cleaned up my mess, started the bike and turned the petcock on when I pulled onto the highway. No problem since, so I just figured it was a piece of trash that had hung up the float needle.

Now, this past Sunday...the bike's been running ragged off idle and popping on deceleration for a while. I checked the intake clamps a week or two ago, and tightened them. A little better, but still not right. I got the old Sportster out to warm it up and try adjusting the idle mixture screw. Turned the gas on, started the bike, and while I was putting my jacket on, I saw gas running out the overflow tube again! Crap...so I whacked the side of the float bowl with a screwdriver handle a time or two, with no luck. Adjusted the screw and shut the bike off.

Decided to take the carb off and clean it out. I pulled the whole works off, manifold and all. Guess what? The rubber band seals were cracked to pieces. Luckily, I had another set, so no problem. I blew through the fuel line and raised the float - it didn't completely cut off the air flow. I took the float off and removed the needle valve and...there was a small piece of rubber caught on the seat. Looked like a sliver of fuel line hose. Anyway, cleaned it out, checked the accelerator pump diaphragm, blew out all the jets and passageways and put it back together.

Man, those new rubber bands and aircraft clamps were a bear to get on. Got it all together and went for a warm up ride. Pulled a lot stronger and popped very little, but still had some hesitation off idle. Went home and turned the screw out another 1/4 turn. Rode down to the gas station and it ran great. Mission accomplished, as the sun was setting.

 

Soak the jets in penetrating oil at least overnight. For the slow jet you can fill the passage; for the main wrap some paper towel around it and soak the paper towel.

Put the carb carefully in a vice with some shop towels wrapped around it. Be sure the vice is well attached to the bench. Use an exact size screwdriver for each of the two jets. Push down hard so the screwdriver does not slip out - the carb and the vice have to be well secured for this. I ground down larger screwdrivers on my bench grinder until they were exact.

Also, perhaps you might wait to see what advice others may give.

 

Thanks for all your help Mick, I'll give that try. I've got a long way to go but if I take things one at a time I should have a decent bike when I'm done.

 

Got her running!!!!! Actually idled for a bit. Now.....there was alot of smoke, backfiring, a flame or two out the pipes. Are these signs of carb adjustments? I may have crappy gas too. But things are looking good.
I am also running with no air filter, does this make a big difference as far as just getting everything running again? I've noticed I have to keep it almost fully choked this way to keep it running.

 

Sounds just like my '69 XLH the first time I started it after a rebuild. It ran rough, coughed, sputtered, wouldn't idle worth a damn, shot fire out the pipes and backfired out of the carb. Good times.

I used an unlit propane torch to test for intake air leaks, and sure enough, I didn't have the intake manifold on right. Took the carb off, re-installed the manifold, O-rings, and clamps, the difference was night and day. No more shooting flames and I was able to adjust the carb without having to worry about setting myself on fire.

 

Leaks at the cylinder head, either intakes or exhausts, will kill the engine quickly - often by burning a hole in the piston. This is something to be taken very seriously. Here are my notes ...

Intake And Exhaust Leaks Tests

You cannot get a good tuneup if there are intake leaks or exhaust leaks.

1. Check for Intake Leaks

With the engine idling spray WD-40 or propane gas around the carb/intake/cylinder head joints. WD-40 is said to work well because it has very fine spray droplets. Propane is best because it leaves no mess, and is most easily sucked in thru leaks. Be careful to not allow any of either to get sucked in thru the A/C as this will invalidate the results.

Any change in engine RPM is a leak which must be fixed.

EDIT: Experience is that this procedure will identify larger intake leaks, but it may miss very small leaks that also must be fixed. And that propane is definetly the better choice.

2. Check for Exhaust Leaks

Pour about 1/2 ounce of oil into each cylinder thru the spark plug holes. Run the engine at idle. You will get lots of smoke for about 5 minutes.

All smoke should come from the ends of the exhaust pipes/mufflers. Any other is a leak which must be fixed.

 

Well..next problem. Got the bike running/idling then I went to start this morning and nothing. I have lights but NO spark. The oil light and generator light are both on so I know I have juice. Could my generator be bad? I'm sailing into unchartered waters here. I'll be reading the FM.....please steer me in a direction I almost had her alive again. Thanks, Jeff