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ZR 600 fouling

1159 Views 7 Replies 6 Participants Last post by  hotrod
1998,carbed,800+ miles on it. Runs good if you keep it to the handlebars,but stuck in traffic or any slow running and the plugs will foul. Black, gas/oil mix will leak from exhaust ports. Had the carbs apart a couple times. Can't find anything,but did install new needles and seats,and eventually adjusted air screws out 1/2 turn. Checked oil pump settings,right on the mark. Checked compression,manual doesn't say,but whould think 130 [email protected] is sufficient. Plugs are always wet and clean around rim,but electrodes are slightly black. Spark "looks" good but don't know if I have tool to check,if there is one. Assuming it is OK,as it starts first time,every time,hot or cold. Any help would be great. Probably some simple thing I'm missing.

Bob Quaif
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what kind of plugs you running? Those thing wire ones? my uncle swears till his death those thigns are total and utter shit. Have you checked your fuel? throw in a bit of dry gas and maybe drain the tank and put in fresh. I am betting you have run a tank or two through and that isn't it but I might as well offer that.
Are you running the right main jets?

Mean Green Racing
Elyria, Ohio
good question i didn't think of that. Important thing to check.
Have you checked the float level to ensure that it is actually shutting off the gas flow before it's flooding out the engine?

2001 ZL800
Delta IIs
Power Breather
MBRP Silencer
Coupling Kit
Goodwin Clutch Kit

Creek beds don't make good brakes!
Here's how to check your main the sled on a long staightaway wide open. Then hit the kill switch or turn the key off with the throttle still held wide open.Pull the plugs and the positive part of the electrode should be a light cardboard color.Black is too rich. If there white your in trouble. The first three threads should also have oil on them. Now thats you main jet. To check your needle position do the same test a 1/2 throttle. Hope this helps some one.

Later Vmaxyam

Bit complex vmax. The way we do a similar thing is this. Take it for a rip. Open it up good. Come back shut down normal slow down hit the switch. Pull the plugs and check them. DOn't need to do what you said to be able to detect rich or lean on the plugs.
To troubleshoot this problem completely it would help to know if the machine was fine then started acting up or if it's always been this way since you owned it or if it ran fine last year and hasn't this year. Also the fact that it runs fine at WOT would send me looking not at the mains but at the needles and clip position and the needle jet size. Can help you pin point the problem with more info.
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