[rideOn]

i cannot maintain a constant idle and have to tweak the carb constantly. i have factory exhaust on '08 classic. i have inspected the exhaust and cannot find any visible signs of leakage. i've used pilot jets in all combinations from 17.5 to 37 with 120 - 130 mains. it runs ok at high rpms, but i have to keep the idle adjuster in really far to idle on it's own. the mix screw has to stay nearly all the way in in any of the above combos.

i re-torqued the heads and prior to that only saw slight oil seepage at one corner of the head, so i assume no problem there. i have taken the carb apart several times recently to clean and swap jets. i replaced the factory rubber inlet with radiator hose and heavy duty clamps.

it sounds like a nice air leak or pilot circuit problem. is it time to just throw this carb out and stick the 30mm tiawan unit on?

[hoppyre]

Try this, start her up, try to get it to idle, spray some WD40 around all the joints from the head to the carb. If the idle changes, you found your vacuum leak. If that doesn't show anything, check your valve adjustment. Since you retorqued the head, valve clearence may have changed.

Also, if you decide to get the 30mm carb, you might want to get a free-flowing exhaust and air filter. Then rejet the carb.

[The Garbone]

Have you removed all that PAV junk?   That adds a point of failure and was the first thing I put in the circle file when I got the bike.

[Bullet.wagon]

I would check compression then ignition If you haven't already.

[ace.cafe]

If the idle air bleed screw has to say all the way, I would suspect some foreign material blocking the pilot circuit somewhere.
Or there's an air leak at the PAV tube, or perhaps a failed/eaking PAV unit.

You can eliminate the PAV question by temporarily plugging the hose connector on the intake manifold that leads to the PAV, so that the PAV is removed from the intake system, and the hole at the manifold is plugged and doesn't draw air into the intake manifold from that hole.
Then, if things begin to change, the PAV is suspect.

For blockage in the carb, it would have to be cleaned out well, and see what happens.

I've set up a few different types of carbs, and I find the OEM carb is one of the  easiest to set up and adjust, so it should be easier than a totally new carb setup to get working right.
I still have the OEM carb on my bike, and I've been able to adjust it to handle a wide variety of changes, and it responds.
The OEM carb  really isn't a bad carb. It's basically just like a Mikuni.
But if it gets dirt lodged somewhere, it doesn't work right, and that does happen from time to time.

One thing that's important for a steady idle, is to adjust the screw settings after it is warmed-up. Because if you adjust it when it's still cold immediately after starting, it makes the idle want to drop off and die when it's warmed-up during your riding.
Sometimes that means you might have to babysit the throttle for a minute or so during warm-up, but it should be stable when it's warmed-up and you're riding up to a stoplight, and shouldn't die-off when it's hot.

[rideOn]

the pav is gone and the compression is 120. i had a little problem with compression awhile back and have found the tappets going out of adjustment extremely quick, but currently they are good. i have not tried wd40.

ace, that is what i thought too. when it runs, it has to be high rpm's, which tells me pilot problem for not wanting to idle. i've blown carb cleaner through every orifice in the carb and the liquid shoots through it ok, at least seems to. you are right, this is a very simple carb and that's what bugs me so damn much.

i have seen threads about the needle height and don't think i'm real clear on that.

[PhilJ]

The needle height should not effect idle. It is more for low to mid throttle settings. If the needle height is off it would cause a stumble when advancing the throttle.

[ace.cafe]

the pav is gone and the compression is 120. i had a little problem with compression awhile back and have found the tappets going out of adjustment extremely quick, but currently they are good. i have not tried wd40.

ace, that is what i thought too. when it runs, it has to be high rpm's, which tells me pilot problem for not wanting to idle. i've blown carb cleaner through every orifice in the carb and the liquid shoots through it ok, at least seems to. you are right, this is a very simple carb and that's what bugs me so damn much.

i have seen threads about the needle height and don't think i'm real clear on that.

The needle height is really only in play from 1/4-throttle to 3/4-throttle, so I don't think that's going to be an issue for your idling problem.

[noisymilk]

Rideon -

I feel you my friend. I am in the same boat. Stock airbox - but figured out I already have a free flow exhaust (assuming the "Classic Exhaust System" sold here by CMW is considered free flow). So getting idle is difficult, as I need to order richer pilot and main jets. I am hoping to stay with the same needle. Most people seem to be able to cure their issues with jetting and stock needle and slide.

Until then, I am running my needle at it's richest position, and getting fair but not perfect plug chops. And the idle is all over the place.

My carb is fully stock. Whats that...can't remember all the numbers. Ridiculously low pilot and main jet though.

My intent is to (all at once) get the Ace airfilter, new jets for experimenting, and new rubber for the choke valve and throttle cable. Mine are pretty aged. I believe this should put me in a good place to work out all of my problems....along with yet another intensive cleaning of the carb.

Stick with it man...its so worth it. And yeah, I keep needing to adjust my rods as well. The exhaust one keeps getting progressively tighter every few days, making starting extrememly hard. Do a quick adjust, close it up....one kick! Gotta figure that one out as well.

Good luck to you. Glad you are still able to ride this year. Down here in the desert, its getting lovely all the time for riding.

Be safe.

[rideOn]

Rideon -

I feel you my friend. I am in the same boat. Stock airbox - but figured out I already have a free flow exhaust (assuming the "Classic Exhaust System" sold here by CMW is considered free flow). So getting idle is difficult, as I need to order richer pilot and main jets. I am hoping to stay with the same needle. Most people seem to be able to cure their issues with jetting and stock needle and slide.
Be safe.

I can't get it running long enough to take on the road to do plug chops. I am considering winterizing the bullet for now and pick back up in the spring. L'il blackie is running great right now, so i'm covered on a bike. I have some body work in mind for the bullet that can happen thru the winter.

New rods are on the list because of the adjusting i'm doing. Not sure which ones. The alloy was recommended and cmw has the hollow steel in a performance pack, so i figure they are ok also. Any feedback out there?

Just for kicks and giggles, i might be thinking about all the crazy performance engine mods: big bore, high-lift cams and stage two heads. That would depend on the tax man and available $$$. You know.

Tell me about the rubber around your choke and throttle. Mine is cracked at the throttle and the one at the choke keeps sliding up while the nut holding the choke piston keeps loosening.

[ace.cafe]

I can't get it running long enough to take on the road to do plug chops. I am considering winterizing the bullet for now and pick back up in the spring. L'il blackie is running great right now, so i'm covered on a bike. I have some body work in mind for the bullet that can happen thru the winter.

New rods are on the list because of the adjusting i'm doing. Not sure which ones. The alloy was recommended and cmw has the hollow steel in a performance pack, so i figure they are ok also. Any feedback out there?

Just for kicks and giggles, i might be thinking about all the crazy performance engine mods: big bore, high-lift cams and stage two heads. That would depend on the tax man and available $$$. You know.

The steel pushrods are stronger, but might be a little noisier.
The aluminum  ones expand with the heat a little more, so they can be a little quieter, but they don't have near the strength of the steel ones.

When you get ready to do some hi-perf mods, speak to me about what you want to achieve, and I can get you there..

[rideOn]

The steel pushrods are stronger, but might be a little noisier.
The aluminum  ones expand with the heat a little more, so they can be a little quieter, but they don't have near the strength of the steel ones.

When you get ready to do some hi-perf mods, speak to me about what you want to achieve, and I can get you there..

i will. looks like these things can really get tweaked.

[grumpyed]

You might check the carb cap gasket and throttle slide and bore for ware.

[rideOn]

You might check the carb cap gasket and throttle slide and bore for ware.

i'll check that gasket. i've had the carb several times trying to fix it. it's a low-mileage bike (1900), so i hope the bore ain't that worn.