86 FZ600S high idle issue

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86 FZ600S high idle issue

Postby d2thomas » Mon Jul 23, 2012 5:07 pm

Hey all, looking for some advice on what to do / look for to resolve this last issue before I can actually ride my bike (it's been since 2004 since I was able to ride). I've been looking online / in forums but have just not seem to find that one a-ha post that helps me out.

I picked up this 86 FZ600S Vance and Hines for basically a steal. All it "needed" was the carbs looked over and a new voltage regulator / rectifier. I pulled apart the carbs, cleaned the primary and idle jets, emulsion tubes, cleaned out the bowls, etc. They looked very good - the bike has about 15k miles on it and has sat for the last 3 years. Anyway in addition to that I had to bleed the brake lines, lube the clutch cable, change the oil, replace the fuel lines / filter, get a new battery.....

I get everything back together and get the battery charged. I fire it up and after some gentle coaxing she comes to life. After some tinkering with the idle adjustment she comes in at around 1250, which ironically I later read is the recommended idle. So I grab a helmet and hop on....here is where the fun begins....

I run it around the neighborhood a few times and almost instantly notice it is now idling at 3000 RPM. Once the idle is up to 3k, nothing can bring it back down. I've tried adjusting the idle however then it's too low for the bike to start. Something is making this thing idle high when it's warmed up and I have no clue what it is.

Any and all help with this issue would be amazing. I told myself I was going to take my time on this bike and enjoy getting it ready but being so close and wanting to taste that wind (after so long missing it) I'm starting to get a bit exasperated.

Advise / ask away!

Thank you!

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Re: 86 FZ600S high idle issue

Postby Murat » Wed Aug 08, 2012 9:30 pm

Check the carb boots for cracks or missing vacuum caps. Carbs might be out of sync. Good luck.
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Re: 86 FZ600S high idle issue

Postby Evilchicken0 » Sat Dec 01, 2012 6:13 pm

It could be time to splash some cash, take it to a dyno and get it set up properly. They'll be able to find the cause using a dyognostic whereas you could chase it around for ages.
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Re: 86 FZ600S high idle issue

Postby HybridSport600 » Sat Dec 01, 2012 8:11 pm

ok, let me understand you better, it idles fine till you throttle it, then wants to stay around 3000rpm, and will not drop down at all? many things can cause this, such as leaking intake boots, worn out emulsion tubes, bad choke valves, too large of jets, or even clogged jets forcing the engine vacume to pull gas from the next recorsful passage, or the pilot screw is incorrectly abjusted, too high of fuel level in carb...etc, as you can see I will need a little more detailed info as to what your doing to it, and the results of that. from what I have to go on, I would say your carbs are either pulling more fuel or air from an aparent leak and or blockage, which is the response of the previous user posts.
answer these for me:

1. how did it accelerate wher riding?

2. where the carbs gone thorough?

3. what did they look like?
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