1981 Kawasaki CSR idling too high

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CSXfan · #1 Unread post by **CSXfan** » Sun Jul 01, 2007 3:36 pm

Hi all,

I'm new to this forum and new to riding, so I apologize if this question has been asked before. I acquired a 1981 Kawasaki 250 CSR from my uncle and it runs fairly well except for one thing. When I first start it up it idles at about 1500 rpms. It stays it that level for a while until the engine warms up. Then it slowly idles up to exactly 4000 rpms. It will stay there unless I rev it above 4500 and let off the throttle. It that point it idles back down to 1500 for about 30 seconds before repeating the process over again.

Is this normal? If not, is there a relatively easy fix? Thanks in advance for your help.

#2 Unread post by **Sev** » Sun Jul 01, 2007 7:01 pm

Sounds like it's time to clean the carbs, then set the float heights, and then bolt it all back together and set the idle.

CSXfan · #3 Unread post by **CSXfan** » Mon Jul 02, 2007 3:33 pm

Thanks for the reply. I've already cleaned the carbs but I didn't do a very thorough job nor did I mess with the floats. Tomorrow I will take it apart again clean everything up. I'm not sure how to set the float height or where to set it. Any advice or suggestions?

Is there any chance that the problem is a sticky throttle cable? Thanks again.

thespirit · #4 Unread post by **thespirit** » Tue Jul 03, 2007 2:04 am

If it was a sticky throttle cable, I don't think it would go down after you rev it up...

When you take the carbs apart, check the choke plungers to make sure they are seating all the way back down. Also make sure they aren't "sticky" feeling. They could be sticking slightly up.

Checking your float height is pretty easy. You can buy a special tool, or just use a good ruler. With the float bowl gasket in place, you hold the ruler on the gasket surface and measure to where the top of the float is. Make sure that the float needle spring is not compacted at all. You want the float to be just barely resting on the float needle.

This is another, more accurate way of doing it: http://www.xs11.com/tips/maintenance/maint20.shtml

CSXfan · #5 Unread post by **CSXfan** » Wed Jul 04, 2007 5:03 pm

Thanks for the reply.

I went for a short ride yesterday (my first on main paved roads) and man was that fun! The bike was still idling at 4-4.5k so it wasn't very smooth, but it was still a great time.

I took the carb out today but in the process I broke part of the choke assembly.

Just to see if I broke anything significant I put it all back together and started it up, but the choke gets stuck fully on or fully off. I'm so mad at myself I can barely see straight. I'm taking the carb to a Kawasaki dealer tomorrow to see if anything can be done. If not I guess I'll have to get a new carb that's probably worth more than the bike itself.

Sorry for the rant, I just had to vent somewhere.

thespirit · #6 Unread post by **thespirit** » Thu Jul 05, 2007 1:50 am

CSXfan wrote:Thanks for the reply.

I went for a short ride yesterday (my first on main paved roads) and man was that fun! The bike was still idling at 4-4.5k so it wasn't very smooth, but it was still a great time.

I took the carb out today but in the process I broke part of the choke assembly. Just to see if I broke anything significant I put it all back together and started it up, but the choke gets stuck fully on or fully off. I'm so mad at myself I can barely see straight. I'm taking the carb to a Kawasaki dealer tomorrow to see if anything can be done. If not I guess I'll have to get a new carb that's probably worth more than the bike itself.

Sorry for the rant, I just had to vent somewhere.

Unfortunately, things like this happen. It's all part of the learning experience. Hopefully it won't be too expensive.

CSXfan · #7 Unread post by **CSXfan** » Sun Jul 08, 2007 5:02 pm

thespirit wrote:
CSXfan wrote:Thanks for the reply.

I went for a short ride yesterday (my first on main paved roads) and man was that fun! The bike was still idling at 4-4.5k so it wasn't very smooth, but it was still a great time.

I took the carb out today but in the process I broke part of the choke assembly. Just to see if I broke anything significant I put it all back together and started it up, but the choke gets stuck fully on or fully off. I'm so mad at myself I can barely see straight. I'm taking the carb to a Kawasaki dealer tomorrow to see if anything can be done. If not I guess I'll have to get a new carb that's probably worth more than the bike itself.

Sorry for the rant, I just had to vent somewhere.
Unfortunately, things like this happen. It's all part of the learning experience. Hopefully it won't be too expensive.

Well $316 for a new carb is a little expensive. This is what happens when I mess with stuff that aint broke. I end up breaking it. It's terrible timing though. In 6 days I'm supposed to take the MSF course.

Check out this thread for a better explaination of my new (bigger) problem. http://totalmotorcycle.com/BBS/viewtopic.php?t=23544