TOPIC:

Hey all,
I tried searching for this problem, but I couldn't find anything on it. My engine will randomly hold the rpms that it's at when I go to shift, and usually it won't come down until I put a load on it. It seems like it could be the throttle cable, but I checked that, and it's definately not sticking. Is it a vacuum leak? Has anyone else had this? By the way, I posted a while back about building my own wiring harness, and I finally got around to doing it, finished it a couple of weeks ago, and everything works great. Thanks for the help!
Jon

Sounds like a vaccum leak to my for sure. Is it spitting or poopping as well? Even if its not its deffinately a vaccum leak in my opinion.

So where do I start?

whatever wrote:

By the way, I posted a while back about building my own wiring harness, and I finally got around to doing it, finished it a couple of weeks ago, and everything works great. Thanks for the help!
Jon

Think you could bring your self to build another harness for a 77 Kz1000??? Sure could use one..... PM me with a price to do so. Sorry for hijackin the thread.

spray so starter fluid around the carbs at idle. If it dies there is a vaccum leak. Then check the obvious, are all the vaccum connections pluged or hooked up the petcock. If they are its probably your intake boots. I had this problem when my vaccum line came undone.

+1

my favorite answer. spray wd-40 around the carbs, particularily on the rubber hoses between the carbs and the motor. if it increases the idle wen you spray it, then you have a leak.

what i did was buy the intake boots from z1enterprises and it fixed the problem right up. just somethin to check for

Thanks guys, I'll check that out.

Spraying starter fluid is really a fire hazard. Use WD40. As far as your throttle cable, it doesn't need to bind; just not have sufficient slack. Make sure you can see slack from where the cable holder bracket is located down to where the end of the cable goes into the bellcrank. Last, there are MANY reasons for air leaks; carb holders are only one of them. I am sure I just typed up a long list for someone else in the last day or two.

Also check in your emissions system, the vacuum hoses may be cracked I had the problem for weeks and months. Do you remember that WG?

WiredGeorge,

The list you graciously typed up a couple of days ago was for me (Viking10), and it was much appreciated. I am taking the liberty to copy your advice in this post; I hope you don't mind.

"You have an air leak in the pilot circuit as you have already guessed. Replace the carb holders... there is not point in messing with old rubber bits. They are replacement items.
Next, you may have leaks elsewhere. Here is my favorite list of things to replace...
1. Remove pilot mixture screws. Replace o-ring on those screws and set them 1.5 to 2 turns out. Will discuss setting in a second.
2. Check vacuum hose off #3 carb all the way to the petcock, inspecting for any holes. Replace, if necessary.
3. Check the vacuum cap on #2 carb for any sign of leaking; replace if necessary.
4. On a stock bike, you should have a hose coming off the vacuum fitting on #1 carb and #4 carb. These go to a tee fitting. The tee fitting has a vacuum hose coming off and going to a canister. This is a vacuum switch that opens your reed valves. Check these hoses for leaks. If this junk is no longer on the bike, make sure #1 and #4 are capped with new vacuum caps... use 7/32" for your vacuum caps.
5. Replace carb holders as noted already. When in doubt, throw the old ones out!
6. Next time idle hangs up; jiggle the choke rod knob in and out a tad. If the idle immediately settles, the choke plunger pads are hardened and not seating.
7. Adjust throttle cable so there is visible slack between the cup that hold the end of the cable sheath to where the very end inserts into the bell crank.
8. Exhaust gaskets leaking... if you had the system off, the gaskets that sit between the pipe flanges and cylinder head are crush type. THEY MUST NOT BE REUSED otherwise air will leak into the combustion chamber.
9. Bad gasket /seal on the reed valves (these are atop the valve cover... there are two with big hoses coming out).
One or some of these things will fix the idle issues. Make sure the sync mechanisms are not hanging up any on one of the carb holder screw ends or the holder itself isn't turned and catching the sync mechanism when you rotate the throttle.

Norseman