81 kz550 weird running issues

wrenchmonkey wrote: I just took a pic of mine but can't seem to upload it from my phone. Ill upload it from pc here in a few minutes.
But yes, there is a screw between carb 1 & 2. Sticking straight up along front edge.

OK. Here's a pic of the screw in question. Mine has a 13mm nut on the top so it can be adjusted by hand while riding (well, pulled over but while out on the road). I don't think this nut is stock but was added by the PO.

Hope that helps!

Ok thanks for the pic. On my bike there is a slotted screw with a lock nut there. There is also another screw that appears to be a throttle stop for WOT.

Check out Loudvx 's posts and pages on the 550 TK22 carbs. He has the links on his posts and I think it is in the archives here. You can modify the high idle setting so it doesn't scream and it can be adjusted for ambient temperature cold start with a thumb screw vs. stock - wrench is needed. It worked very well. My 550 was not as cold blooded as stated here, but if I wanted to leave immediately the choke had to stay on for a couple miles 2-3 minutes. Always idled great after that. R

My buddy's Kz550 seems to start instantly, and comes off choke relatively quickly. He did the fast idle modification too. that helps a lot.

gpzweb.s3-website-us-east-1.amazonaws.co...astIdleScrewMod.html

I had the same issue a while back. Found out one
Float valve was longer than the others, making
The level lower in the carb. That and a vacuum
Leak on the same carb made for a bad bad day
And some $$$.

OK here is a little update. I performed the Fast idle mod today. What a difference that makes. Much happier now. You can start it up and not go to 7k. Adjust the choke a little and can actually ride it after a few minutes instead of having to let it warm up for 20. Much better. Thanks.

Wildman1024 wrote: OK here is a little update. I performed the Fast idle mod today. What a difference that makes. Much happier now. You can start it up and not go to 7k. Adjust the choke a little and can actually ride it after a few minutes instead of having to let it warm up for 20. Much better. Thanks.

Yes it is very useful. I have found that in the spring/fall (cooler temperatures) I need to increase the fast idle. During the summer heat I need to decrease the fast idle.

I would like to ask Loudhvx: How do you press a nut onto an allen head bolt? I would like to do this so I don't have to carry an 8mm wrench.

The_Proletariat wrote:

Wildman1024 wrote: OK here is a little update. I performed the Fast idle mod today. What a difference that makes. Much happier now. You can start it up and not go to 7k. Adjust the choke a little and can actually ride it after a few minutes instead of having to let it warm up for 20. Much better. Thanks.

Yes it is very useful. I have found that in the spring/fall (cooler temperatures) I need to increase the fast idle. During the summer heat I need to decrease the fast idle.

I would like to ask Loudhvx: How do you press a nut onto an allen head bolt? I would like to do this so I don't have to carry an 8mm wrench.

I believe the nut size I used was 3/8. I used my bench vise to press them together.

I think I just pressed them together in a vise, using a short pipe with a 5 or 6 mm ID. It was a long time ago (20 years?). I used a stainless nut. It's possible I drilled the inside of the nut to get the hole to the right size, but I honestly don't remember.

Tried the vice and the nut went on crooked. Will try again soon.