KZ550 High Idle

First post. Great forum - you all have been a lot of help already.

I just bought a 1980 KZ550A1. It is in great condition, but the engine idle is a little high. It starts out at around 750 rpms, but once it is warm (post interstate riding) it stays at around 3000.

Anyone know what I could look at that might be a simple fix? I will probably take it into a mechanic soon to get it looked over (though whatever they diagnose I will try to fix myself), but if there is something simple I am overlooking then I could save some time/$ adjusting it before taking it to them.

The idle adjust screw is all the way out.
The throttle cable looks loose enough when released, and it seems that the throttle is closing all the way.
The decelerator cable is broken - would this cause the problem?

Don't know what else to check . Is there some adjustment to tubes or carbs that could help this?

-Thanks

Try checking for vacuum leaks around your carb boots. Spray carb cleaner at the boots at its lowest possible idle without stalling. If the spray kills the engine or makes it rev up there's a leak

I went through your advice and sprayed card cleaner on the boots and didn't see/hear much. However, I was looking around the engine for other visible leakage areas and saw this. That doesn't seem like it should be happening. Thoughts?



The gasket in the video has some oil leakage in the front, so I knew it wasn't tight. However, I didn't know it was that bad.

yup. that's bad. looks like time for a new head gasket. :pinch:

I figured as much.
Any words of wisdom on the process? I have a KZ550 factory manual, and hopefully could follow it's instruction.
I once replaced a cracked head and therefore gasket on a 1997 Jeep Wrangler, but I'm guessing a motorcycle is a different story.

Hit up a member loudhvx. he has a wealth of information on 550s in the signature line of all of his posts. Good luck, Paul

That's tough. I wonder what caused it. Does it look like soeone had the motor open before?

Anyway, take a look at the various manuals and other links in my signature.

WOW !!!!
I have seen bikes that were beaters,,Just wore out,,Beat near to death,,even bikes guys tried to kill because they hated them.
I have been working on bikes since Z1's were on dealership floors NEW.

And I HAVE NEVER SEEN ANYTHING LIKE THAT BEFORE.

Lets just hope the last guy didn't know how to clean a gasket off or used some cheap piece of crap.

WOW again.

Mike

Not sure if the engine has been opened before; don't know what the signs of that are.
It is a bit old: has 30k miles.

OK so my final inquiry for this topic:
Would the head gasket be causing the high idle? Or is there something else amiss to look for when I replace the gasket?
And more importantly, should I replace the gasket(s) myself, or is it too complication and something I should take into the shop?

Alrighty. So you all thought I had just gone and abandoned this issue. I sure hadn't! I have been working on it diligently since I was last on here, and just got done yesterday putting everything back together.

I took everything apart and got the cyl head off. Replaced the valve seals, did a valve adjustment, put a new cyl head gasket on, and new gaskets/o-rings for the tensioner and exhaust.

So after doing all that, and working hard to get it back together, I am in more trouble. When I tried to start it it would not turn over. And worse, when I put it in gear but have the cluth in, it wont roll.

Anyone have any thoughts on what I could have messed up?

Oops.