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Old 08-17-2009, 04:42 PM   #1
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Default Inconsistent Idle- Bearing Leak?

My Grp tuned started idling inconsistently. Sometimes when i come off the throttle it's at a high idle, sometime a low idle. If i just let it idle it will go from low to high and back again. The only leak i could find is the front bearing. If i open the carb and blow through the fuel intake i can hear some air coming from the front bearing. Is this significant enough to be the reason for my idle problem? I've already went back to factory needle settings and re-tuned to the same result.

I just figured i'd ask before i spent $15 on a new TKO. Thanks
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Old 08-17-2009, 05:10 PM   #2
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I've been there. Change the front bearing.
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Old 08-17-2009, 05:11 PM   #3
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I saw a post 2-3 weeks ago that explained how a front bearing can be completely open and have no effect on anything like that... that the shields are just for dirt and not vacuum.

It was in this off-road forum if you wanna search for it.

EDIT: Correction, it said it would have an effect on tune... but people tune to open bearings just as you'd tune to sealed bearings.
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Old 08-17-2009, 05:21 PM   #4
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A short burst of WD40 will let you know.
With the engine running, aim the straw
of your WD40 at the back of the flywheel
and give it a short burst. If it shuts the engine
off, then you know the bearing is leaking and
the bearing needs to be replaced.
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Old 08-17-2009, 05:22 PM   #5
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Quote:
Originally Posted by Semple View Post
I've been there. Change the front bearing.
You had the same idling problem, and the bearing solved it?


Quote:
Originally Posted by markr04 View Post
I saw a post 2-3 weeks ago that explained how a front bearing can be completely open and have no effect on anything like that... that the shields are just for dirt and not vacuum.

It was in this off-road forum if you wanna search for it.

EDIT: Correction, it said it would have an effect on tune... but people tune to open bearings just as you'd tune to sealed bearings.
I found that post, but now i'm confused on what to do to fix my problem. Looking for more opinions.
Quote:
Originally Posted by rageworks View Post
A short burst of WD40 will let you know.
With the engine running, aim the straw
of your WD40 at the back of the flywheel
and give it a short burst. If it shuts the engine
off, then you know the bearing is leaking and
the bearing needs to be replaced.
That's what i was looking for, i'll try that this evening and let everyone know.
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Old 08-17-2009, 06:21 PM   #6
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Weird, i go out there to check the bearing with WD-40 and the idle is fine. The engine was very rich for some reason. The only thing i can think of was that there was a leak that i fixed yesterday when i checked/resealed. That caused the engine to go back to normal so making it rich. I have to go now, so i'll keep trying later/tomorrow. Thanks Guys.
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Old 08-18-2009, 07:04 PM   #7
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could be losing pressure some where. check pressure on tank, and exhaust seals. Could have a hole in the presure line. Hope this helps.
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Old 08-18-2009, 07:54 PM   #8
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Might only happen when hot like running race pace for a few min.Alum blocks grow a bit when heat soaked & then the problems show up.Worth a check if the neibors dont get mad.
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Old 08-18-2009, 10:08 PM   #9
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Quote:
Originally Posted by bigde2001 View Post
could be losing pressure some where. check pressure on tank, and exhaust seals. Could have a hole in the presure line. Hope this helps.
I actually found that my pressure line was melted at one spot. So that may have been the problem. Once i fixed that, the engine richened up. The tanks/seals were good.

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Might only happen when hot like running race pace for a few min.Alum blocks grow a bit when heat soaked & then the problems show up.Worth a check if the neibors dont get mad.
I'll get some tanks in tomorrow, so hopefully i can compare to see if it only happens when it gets hot. I live in the country, so i don't have to worry about neighbors. Except for my grandparents who live across the street. It's like "Everybody Loves Raymond"
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Old 08-18-2009, 10:49 PM   #10
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I'm so sorry
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Old 08-19-2009, 07:21 AM   #11
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Quote:
Originally Posted by Cory Kerber View Post
You had the same idling problem, and the bearing solved it?
Yep. My bearing was leaking, to the point of leaking a puddle under the engine mount. My idle was erratic. Wouldn't hold a tune, kept leaning out, etc.
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