Since I am a newbie got a stupid question

I know that I need to rebuild the petcock on my bike. It runs fine on reserve. Is there any downfalls to running the bike on reserve compared to the on position? In the on position whenever I rev the engine up past three thousand RPM's it will just cut out and not start kicking again til it comes back down to idle. But in the reserve position it runs great. I just had the tank repainted and I think that the diaphram might have got some crap in it at that time. just wanted to make sre there will be no adverse effects on anything for the time being.

David

I don't see any problems running on reserve... cept that you may forget to fill up, and run out! The carbs don't know the difference...

sounds like some trash on the screen inside the tank, since you just got it painted, maybe the dust from sanding is still inside the tank, and has plugged up the screen

Unless the reserve spout is missing the screen and you are siphoning garbage into your carburetors. Do you have a inline fuel filter on the feed line? If not than I would strongly recommend that you put one on. At that point it makes no difference weather you are on main or reserve. Unless you have a vacuum petcock in which case it is a totally different story.

Otakar ,Just wondering what difference it would make if it was a vacuum petcock.I just finished my rebuild and have been using reserve (79 kz1000st)and got a hesitation after idle and was thinking it was my carbs.

A vacuum petcock is actually a vacuum solenoid. I it is not operating properly it may not be opening and not sullying fuel. The reserve is usually a bypass for that system.

With the old bikes running on reserve it "WILL" suck up any trash in the tank, then it will get into the carbs and run like crap. If you like pulling the carbs running on reserve is fine. You can get a petcock at Z1E for under 20 bucks.

As I mentioned before, an inline fuel filter will do wonders also $2.50

I agree running in reserve is ok except for the fact that all the garbage at the bottom of the tank will go right to the carbs. A in line fuel filter will solve that problem for a couple of bucks but remember to change the filter when you do an oil change to keep fuel flow good!

bigD82kzltd wrote:

...need to rebuild the petcock...runs fine on reserve...just had the tank repainted and I think that the diaphragm might have got some crap in it at that time....

Oem Vacuum petcock on 1982 KZ1000LTD (see image below)---

Would remove petcock from the fuel tank, then disassemble, inspect, and carefully clean petcock pick-up tube screen and petcock internal parts.

Likely find grit or crud on the screen or inside the petcock impairing the diaphragm action, 0-ring, spring, or position gasket.

But the diaphragm or 0-ring or gasket may be damaged beyond further service, thereby requiring rebuild kit.

If parts look okay, reassemble and see what happens.

In any event, before reinstalling petcock, would remove fuel tank and flush it by fast dumping all existing fuel through filler hole, put in a little fresh fuel, slosh it around, and again fast dump. Idea being to flush loose crud and grit from inside the tank. If desired, may use common household rubbing alcohol for the flushing operation.

Would also check and assure integrity of vacuum hose and connections from carb to petcock.

Good Fortune!

For reference, here's the diagram from kawasaki.com.

[Click on image to enhance view.]

1982 KZ LTD could be 440, 550, 750, or 1000.

Likely get better advice if show bike info in signature, and the next few posts show an easy way to do it.

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