idle rises dramatically with temperature

I have an '83 550LTD,got it for free and am makin a little cafe type thing out of it.took off the airbox, fitted UNI pods, and a MAC 4 into 1 pipe. I went to 112 main jets from the stock 92's that were in the tk22 slide carbs after progressively increasing the size, anything less and it was running too lean, heating up very quickly and my plugs looked white. As the bike warms up, the idle rises, and i have to adjust it down with the adjuster screw. I was riding on the highway for a while last night, and when i got off and stopped at a light, it was up to 3500 rpm! This is my first air cooled bike,was wondering if this is common. Also my first attempt at tuning carbs, so something else might be off. any suggestions?

try adjusting idle after motor warms up

also could be due to an air leak in the intake manifolds does it snap and pop much.

Generaly speaking, if the idle climbs a lot after warming, that usually means youre lean. Do you find you need the choke for a long time?

But in your case, I think it sounds like you must have a vacuum leak. 112 is huge. Even my gpz with pods and open canister didn't need to go that high on the main (we use the same carbs, just different jets).

Are you sure all of the vacuum ports are capped on the intake manifold rubbers? Are you sure all of the rubbers are not cracked or leaking? If you removed the smog device, ther are two manifolds that will need caps on the vacuum ports. (Also, the air ports on the valve cover should be capped.)

Lastly, if the fuel level is too low in the carbs, that may cause you to run lean. Have you checked your fuel level with the clear tubing method.

That motor and those carbs usually are well behaved after a pod and jet change. The RPMs will climb a little as it warms. If it's jetted properly it will only climb by a hundred or 2.

I second the suggestion to just set the idle via the idle screw when its nice and hot. Start it up, go for a short ride, by that time it should be idling high, then stop and turn the screw and see if that solves it. Also make sure you have a little play in the throttle cable and that its not binding up anywhere. Finally, sync the carbs if you have not done so, according to the manual out of sync carbs can cause "erratic idle". Vacuum leak check is also quick and easy. Good luck.

Pods :laugh:

Maybe the advancer is sticking and failing to return to its more retarded idle position when the throttle is closed, which could cause the rpm to remain too high.

Could use a strobe type timing light to watch the advancer move back and forth as the rpm is varied by blipping the throttle.

If needed, the advancer may be cleaned and lubed, which usually eliminates the sticking.

Where a timing light isn't available, just manually move the advancer to check its free functioning, and lube it anyhow for good measure.

Good Fortune!

Im pretty sure all the vacuum plugs are in, I was pretty thorough last time I had it apart, which was a few days ago to go to the 112 main. The dynojet kite listed the 112's as for the LTD, and 108s as the LTD alternate. it also came with 98's and 102's, I tried all of them, increasing every time. The fact that you said its generally a lean thing made me realize that I hadnt changed the pilots, as the kit only came with mains. by that logic, wouldnt this make the bike lean at idle?

oldirtybob wrote:

Im pretty sure all the vacuum plugs are in, I was pretty thorough last time I had it apart, which was a few days ago to go to the 112 main. The dynojet kite listed the 112's as for the LTD, and 108s as the LTD alternate. it also came with 98's and 102's, I tried all of them, increasing every time. The fact that you said its generally a lean thing made me realize that I hadnt changed the pilots, as the kit only came with mains. by that logic, wouldnt this make the bike lean at idle?

BINGO.

ok, so anyone know where i can get pilots? the stock ones are 32 i believe, so prob gonna need something in the realm of 38-40 if the ratio is the same as the mains

You are lean at idle, so much so that you have to crank up the idle speed to get on the main circuit in order for it to not die. When the engine warms up, your mixture mixes better so the idle speeds up. Then you turn it back down.

If you set the idle speed while hot, you will have to run on the choke much longer to get it to idle while cold.

If you were truly on the idle circuit, you could adjust the idle mixture with the air screws. Have you tried that?

Unfortunately, I know of no source for pilots on the Teikei TK22 carbs. I just drill them and it works great. Very smooth idle. All four cpark plugs come out the same. And you are right, 32 is stock and you probably want 34, or 37. (Those are the two steps available with the mini drill bits.)
Mow you are going to hear a lot of moaning about not drilling jets, but there is no other way and the moaners don't seem to remember that. If they can link to a source of TK22 pilots (other than the available 32) that would be great. So far none.

If you do a search for drilling jets, you will get a bunch of threads with the details on what to do on the TK22 carbs.

By the way, with the Mac 4-into-1 exhaust, it would not run right at low RPMs until I upped the pilots to 37. But this is on a gpz. You may be ok with 34, but might end up 37 too.