Slight idle hang

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Mnmonster
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Slight idle hang

Post by Mnmonster »

I just did a top end rebuild on my 97 220 this winter. New wiseco piston, boyseen reeds, all new gaskets, and I also had Ron mod my carb and head. Right now I'm running a 40 pilot, 150 main, needle clip 4th from the top, air screw 7/8 turn out. Bike will start on the first or 2nd kick, no choke needed. Idles great. However when blipping the throttle it seems to take a bit too long to settle back down. Its not excessive but it does take longer than it did before. I have double checked everything was tight around the head and intake. I don't believe I have an air leak anywhere. Am I reading too much into this or should I keep digging? Not sure where I should look next. I also did a plug chop test last night and the plug was still pretty white, so I'm thinking I need to go up a size on the main. Any thoughts appreciated. Thanks.
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Re: Slight idle hang

Post by jjavaman »

I did the same thing last year and had the same problem! It was a air leak for me, one of the bolts on the reed block was not tight.
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Slight idle hang

Post by SS109 »

Ron's normally pretty good about getting the jetting real close for you. I would suspect a leak as well.
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Re: Slight idle hang

Post by Jaguar »

check the crank seals for a leak
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Re: Slight idle hang

Post by Mnmonster »

Jaguar wrote:check the crank seals for a leak
I would like to think that this is not a strong possibility as I did not have this problem prior to my rebuild. I will triple check all the gaskets and bolts though.
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Slight idle hang

Post by ohgood »

Mnmonster wrote:I just did a top end rebuild on my 97 220 this winter. New wiseco piston, boyseen reeds, all new gaskets, and I also had Ron mod my carb and head. Right now I'm running a 40 pilot, 150 main, needle clip 4th from the top, air screw 7/8 turn out. Bike will start on the first or 2nd kick, no choke needed. Idles great. However when blipping the throttle it seems to take a bit too long to settle back down. Its not excessive but it does take longer than it did before. I have double checked everything was tight around the head and intake. I don't believe I have an air leak anywhere. Am I reading too much into this or should I keep digging? Not sure where I should look next. I also did a plug chop test last night and the plug was still pretty white, so I'm thinking I need to go up a size on the main. Any thoughts appreciated. Thanks.
the mixture and clip position say your pilot is too lean. richen up the pilot a few measures, retune the clip and mixture, i bet it doesn't hang anymore.
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Re: Slight idle hang

Post by Jaguar »

I disagree since he can start it without the choke
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Re: Slight idle hang

Post by Mnmonster »

Jaguar wrote:I disagree since he can start it without the choke
This is where I get a bit confused as well. Starting without choke would lead me to believe I am rich...however the hanging idle would point to being lean...kind of contradicting.
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Re: Slight idle hang

Post by Mnmonster »

Ok I tried swapping in a 42 and a 152 and then also a 38. No change as far as the idle goes. Same slight hang. See video below.



Am I making too much of this? Right now I have the 38 with the 152 main. I've got some spooge with the bigger main but the bike just rips from 1/8 throttle on up. Slight bog from idle to 1/4 when accelerating hard.
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Re: Slight idle hang

Post by ohgood »

Jaguar wrote:I disagree since he can start it without the choke
i think you're right, too.

meaning.... there is weird stuff happening that should not happen. he's rich when first started (start without choke) and lean once running (idle hanging).

i bet there is a air leak and jet block / fueling issue happening.
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Re: Slight idle hang

Post by Mnmonster »

I tried tightening everything again, reed block, cylinder, and head nuts. No change. I had Ron replaced all the gaskets in the carb, including the jet block.
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Slight idle hang

Post by jjavaman »

Does the slide "snap" shut when you blip it?
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Slight idle hang

Post by Mnmonster »

jjavaman wrote:Does the slide "snap" shut when you blip it?
Yes it opens and closes smoothly and doesn't hang up.
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Re: Slight idle hang

Post by shoe757 »

I would lube the cable just for giggles. It's quick and easy. Other than that I would say rich on the pilot or leaking fuel passed somewhere.
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Re: Slight idle hang

Post by Mnmonster »

Still chasing this. I am not loosing any transmission oil or coolant. No visible leaks of any kind. I've tried spraying wd-40 and carb cleaner all round the intake, base and head gaskets with no change in idle.

Yesterday I took the reed block off to inspect the brand new reeds I installed when I did the rebuild. Here's a pic. You can see a bit of light in the corner. Is this enough to cause an issue? And if so, I believe this would show up as a rich condition, not lean that I am experiencing, right?

Image

Also I snapped a pic down into the piston to find some real nice gouges on my ~5 hour piston. :?

Image

Starting to lose interest in chasing this stuff.
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Re: Slight idle hang

Post by Tedh98 »

Wow on the piston picture. What is your warm up procedure? Is this the first time with a forged piston?

I only see two if the four corners . . . . but I havent seen gouges that deep or narrow with a 4 corner siezure.
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Re: Slight idle hang

Post by Mnmonster »

Yes first forged piston. Had the stocker in it when I took it apart.

Warm up, I just let it idle for about 5 minutes then ride easy for a minute or two. Then ride as normal.
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Re: Slight idle hang

Post by Mnmonster »

Can anybody tell me the inner diameter of the exhaust and intake? I'm going to make a leak down tester and need to order some plugs.
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Re: Slight idle hang

Post by Mnmonster »

Built myself a leak down tester. I did have some small leaks at the reef block but got those sorted. However I have a pretty significant leak still. Lose about 1 psi per minute. Can't seem to locate anything around the intake, spark plug, head, or base gaskets...this would lead me to my crank seals I suppose :sad:

I have not lost any tranny oil, so I assume my problem lies with the left (flywheel side) seal. Is there any way to verify before diving in? I know the bearings and seals are relatively cheap, but what would I be looking at for labor if I brought just my motor in to get split and seals and bearings replaced?
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Re: Slight idle hang

Post by Mnmonster »

Starting tearing everything down. My piston is in way better shape than I thought. The previous picture had me worried. Here are some pics.

Image

Image

Those gouges in the earlier pictures aren't gouges at all. Can't even feel them with my fingernail.

Image

Image

Thoughts?
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