Jetting 550 after mods pods and 4-1

werewolf, I just orderd 98's kehein from Jeff. He was unsure about those threads and the jets in general working for my bike. I have TK and I think you do too right? Are you sure you are using kehein or Keyster? he said Keysters fit but are 95 and then jump to 105(too big).

Our testing can help Jeff out a bit

Oh, another question....

Should the air screws be turned in since the pods allow for more air flow? I am having trouble stalling even after the bike is warm.

Did the bike stall when warm before the pods? That could be valve shims.

Carb jetting and tuning is usually the last step in the chain. First you do a compression test. Then check the valve shims. That is a good time to verify valve timing. Then you check ignition timing and advance-mechanism. ...THen you start messing with carbs and jetting.

You want Keihin jets. I don't know about Keysters. Definitely not Mikuni.

I don't think 97.5 is way out of line (as Werewolf said), but order some 95's too if they're cheap. Try both. Hell, if they're cheap and fit, maybe I'll order some too. I usually drill my own, but 95 is a good starting point for the D1.

I'm running 96.5's in both D1 bikes but both have the airbox now. I'm using the Dynojet needles in the bike with a Kerker and the 3rd notch. I'm using modified stock needles in the bike with a Mac exhaust (which is les restrictive than the Kerker. I cut a new notch in the needle to raise them the equivalent of one notch without the binding and scraping caused by using shim washers. The Mac bike is running a touch lean while warming up so I may go to 98 on that bike.

Post edited by: loudhvx, at: 2006/05/02 02:16

I used Keihin jets, I didn't mention to Jeff that I was putting them in TK carbs, but if you talk to him again, or he happens to look here, the keihin jets of the series number I listed above fit perfectly, the threads are an exact match. My bike would somtimes try to stall when you just roll the throttle normally with no choke when the thing isn't up to full operating temp, when it does (did), I just choke it about 1/3 or just roll it up a bit higher than normal til its warm enough not to do it. I turned the air screws all the way in early today (yesterday now I guess) and it refuses to stall like that again, or has so far anyway. I had just backed them out some a week or so ago, and it started stalling when not up to full operating temp, and still did it at about 1 turn out, so I just turned em in the rest of the way. It sounds much healthier when started cold too.

I wouldn't be suprised if my valve shims are a bit off, and possibly valve timing, but my compression is decent (170-175 on all cylinders when hot). I checked the compression when my uncle was visiting (asked him to bring his comp. tester), but haven't wanted to tear into anything else. I'll probably save it for a deep winter project. I ride most days in the winter when theres no snow/ice on the roads, but theres usually 3-8 weeks in a row with a few inches of snow and/or ice on everything.

If it runs better when it's warm, it may not be the shims. The test for valve shims is to ride on the highway, on a hot day, for a good 20 to 30 minute stretch at a sustained 70mph or higher. Then pull off and come to a stop (preferrably an exit ramp etc. If the bike just dies. Then it may be valve shims. It will usually start right back up if you give it some throttle. Then you'll have to keep revving to stop it from dying. After it cools down a little ( 5 to 10 minutes), it will return to normal operation and will idle as it did before.

The air-screws should be out anywhere from 1/2 to 2 turns (I usually end up somewhere around 1 turn). If they are all the way in, you may be idling on the main circuit. I assume you've checked the idle jets, but next time you're in there, give them and their ports another look. Make sure you can see a clear circle of daylight through them.

It's possible that you are so lean that you have to have the screws all the way in. In that case you'll either need to raise the needles or drill the jets.

To give you an idea, here's what I found: I use the lean-drop method and confirm on an EGA as to where to set my air-screws. (I have the same carbs as you, but it has different main jets).On my bike with the free-flow Mac exhaust and airbox, I had the stock 94 mains as a baseline (but obviously lean). The air-screws ended up at 1/2 turn out. Then I put in 96.5 mains (slightly lean, but ok after full warm up)). The air screws ended up at 1 turn out. If I go to 98 mains, I expect the screws to be somewhere between 1 and 1.25 turns out. That's about right.

Since your only mods are the 4-1 pipe and the pods, I highly doubt you need to change the idle jets.

BTW, do you happen to know what size your idle jets are?

Nevermind, looks like we both use #32 idle jets and the same needles (4D92), and same slide cutaways, when stock.

Post edited by: loudhvx, at: 2006/05/02 11:31

Hey, guess what? I had a spare set of 82/83 KZ550 C carbs laying around. It came from a C that had a 4-1 pipe. Turns out it had a Dynojet kit in it which uses 98 mains. SCORE! (I thought I was going to have to buy another Dynojet kit to get adjustable needles.) Anyway, I guess it means a 550 C with pods and 4-1 exhaust can run 98 as well and not be too far out. Maybe just a thin shim under the needle clip.

Post edited by: loudhvx, at: 2006/05/02 12:16

I tried turning the air screw in but when I reved the RPM seemed to stay up there and take a while to come down. Is this normal? I did this when stationary and backed them back out bc I didn't want to have it like that on the road....

guavatone wrote:

I tried turning the air screw in but when I reved the RPM seemed to stay up there and take a while to come down. Is this normal? I did this when stationary and backed them back out bc I didn't want to have it like that on the road....

Sorry, I should have been using the "quote" feature sooner since we have several 550's in question here. My head's spinning a little :blink:

Anyway, that's not normal. (I assume you know about the knob to control idle speed.) That symptom can be caused by several problems.

If some of your idle jets are clogged and you are idling off the main circuit, that can happen.

Or if the idle mixture is way off, you may end up idling on the main circuit which can cause this.

Any significant vacuum leak will definitely cause this. That means check every vacuum hose for a leak or look for cracks in the rubber intake manifolds.

This can also happen if you are usinmg the choke. That is actually the normal way for the choke to operate on the TK22 carbs you have. That's the only real weak spot on the carbs.

It can also simply be a sticky throttle or cable.

Post edited by: loudhvx, at: 2006/05/02 21:13

I'll check things out. But, my manifolds are new and I have no tubes on them anymore since they are all plugged.

Could it be the vacuum tube for the fuel?

throttle cables seem smooth and not sticking.
thanks i'll look for clogs when I rejet soon.

I went out for another ride with the pilot screws in 1/4 turn from where it was. After riding and warming up more the idle was way hight. When I started adjusting them I heard an intermittent wheezing sound. It sounded like it came from the back of the carbs - maybe it could have been the breather tubes or the crankcase breather. no sure, I am getting an intermittent feul light so I am draining the tank to look inside. more to follow......

Post edited by: guavatone, at: 2006/05/04 23:32