Fast idle after Earshave - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 4 (permalink) Old 04-05-2014, 12:57 AM Thread Starter
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Fast idle after Earshave

I bought a basket case/fixer/parts bike. I did the Earshave/Coastered before I ever got it running (previous owner's mechanic told me it had a bad stator after 50k miles, which I replaced) once I got it running it has been idling high, about 2k-3k, I don't know exactly because the tach needle doesn't move with the RPMs (tach is the next Gremlin after fast idle). I rejetted with the appropriate jets per this forum.

I sprayed starter fluid around the boots to see if there was a leak there. The engine immediately dropped RPMs, which doesn't make sense to me. If there was a leak shouldn't the engine rev higher. I sprayed both boots with the same response, the engine started to bog. Just for S and G, I sprayed towards my K&N air pods, also bogged the engine.

If a vacuum leak is the culprit to fast idle wouldn't it surge when I sprayed starter fluid on it.

I have open and cleaned with contact cleaner, every connection and ground. The carb boots had no cracks that I could see. I tightened all four of the boot clamps.

I have the front air mix screw at 3 turns out and the back at 2 1/2. I had them both at 2.5 initially, but the front plugs looked whitish. Now they both look amber.

Anyone have a clue to what might be the problem with the idle?
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post #2 of 4 (permalink) Old 04-05-2014, 01:03 AM
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either you have a vacuum leak around the boots (which are tricky little bastards to seat properly)

or you simply have your idle adjustment knob twisted a bit too far in

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post #3 of 4 (permalink) Old 04-05-2014, 01:35 AM Thread Starter
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Thanks for the quick response new rider. I failed to mention that I completely dissassembled the carbs and cleaned them, both with carb cleaner and dental brushes. During reassembly I discovered the previous owner/mechanic missed a couple of things going by the book. First, the o-rings were missing from the coasting enricher? I'm going from memory by the name, but it's where you check for proper float level with the Kawi gauge connected to a short hose by the book. I replaced them with OEM Kawi.

Previous owner also had the carb boots wrong by the book. The correct boots were on each side designated by the "F" and "R" stamped into the rubber on each boot, but they were missaligned. The rubber marker was not aliged to the mark on each cylinder head. I alligned the boots per book.

I also added a AGM battery and when I pulled out the battery box it was amazingly clean for a 1990 bike that most likely had a good ol' fashioned battery.

Everything else I have done to spec. I have replaced all fluids and parts with per book recs. That means no syth or irid plugs. I did this for two reasons, a bike, especially a Kawi, should perform well in specs given its engineered diet. New s#!t helps but sometimes hurts, sometimes adding their own Gremlins (Spitfire plugs in my pickup killed the sending unit that cost me $300)

The second reason is I wanted to limit the control sample. I have heard even funky gas can give you wonky reading.
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post #4 of 4 (permalink) Old 04-05-2014, 06:35 PM Thread Starter
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I pulled the carbs out today and inspected the boots more closely. There is an inner ring that molded into the boots that mates with the barb on the intake. They both had chunks taken out of the inner ring. I'm pretty sure thats what makes the seal since the hose clamps aren't that strong. It was most likely caused by the improper mating by the previous owner.

Ordered a used pair on Ebay. I just hope the PO of this pair wasn't a curmudgeon like my girls ex. Fingers crossed!
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earshave , idle too high , tachometer

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