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Old 08-06-2010, 07:01 AM   #1
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Default Wheels spinning by themselves?

I took out my ofna buggy recently and realized the wheels were going by themselves at idle. I took out the engine and had a broken plastic clutch shoe, so i upgraded to aluminum shoes with ofna gold springs. I put the bell back on and it spun freely after tightening the screw. But the wheels are still going by themselves? The bearings weren't locked but could that be the problem? I have about half-gallon through the buggy.

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Old 08-06-2010, 07:07 AM   #2
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could be bearings or could be nothing at all.. running and see if you keep stalling out... or it could be your idle is to high
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Old 08-06-2010, 07:08 AM   #3
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Did you replace the springs with the clutch shoes? is the idle to high and engaging the clutch?
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Old 08-06-2010, 07:09 AM   #4
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If everything with your clutch set up is in working order then it sounds like your idle is set too high.
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Old 08-06-2010, 07:12 AM   #5
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Yes the springs are brand new and bought them with the shoes. Im gonna have to check the idle setting but it was running fine until the shoe broke, and the gap looked like it was set properly (about 1mm) in the carb.
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Old 08-06-2010, 07:16 AM   #6
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or springs are too soft
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Old 08-06-2010, 07:18 AM   #7
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Typically when I put on new clutch bearings (rubber shielded more so than metal) I get a little wheel movement. How much are you talking about? Did you deburr the old shoes?
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Old 08-06-2010, 07:31 AM   #8
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The springs are 1.1 that i put in. And the stock bearings are still in the clutch bell i should be getting a new set today. But the thing that surprises me is that the bearings were still spinning pretty well so i cant imagine its them. I'm going to adjust the idle screw to see if that helps.

Do you think it could be the shimming?
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Old 08-06-2010, 07:33 AM   #9
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Quote:
Originally Posted by 3DRCRACER View Post
Typically when I put on new clutch bearings (rubber shielded more so than metal) I get a little wheel movement. How much are you talking about? Did you deburr the old shoes?
When i lift it off the ground i get a significant amount of movement. And this might be a newb question but what does "deburr" mean?
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Old 08-06-2010, 07:33 AM   #10
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depends how fast they run "by themselves"... if your car has an excellent free wheel, then the little friction in the clutch assembly (bearings... shims... even the vibrations) can be enough to make the wheels turn very slightly even if the idle is set properly - to me this is a non-issue. My car does that sometimes, and I can guarantee the clutch isn't engaging the least.

However - in most cases it's due to the following (non-exhaustive list):
- seized clutch bearings
- weak/broken spring
- unscrewed clutch nut
- wrong clutch/shoe combo
- idle too high

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Old 08-06-2010, 08:03 AM   #11
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If the idle gap is set right, then the low speed needle maybe too lean, causing the idle to be too high, check that and turn it a few hours to the rich side and see if that drops the idle. Be sure to get the engine up to proper temp before tuning it.

And for clutch bearings, you should change those often, keep several sets on hand, and they are cheap, like $1 each from Avid RC.



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Old 08-06-2010, 08:25 AM   #12
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Quote:
Originally Posted by jaykay098 View Post
When i lift it off the ground i get a significant amount of movement. And this might be a newb question but what does "deburr" mean?
The burr is on the side of the shoe, both flywheel side and clutch bell side. The aluminum will mushroom over and could actually hit the bell or flywheel. A dremel will fix this easily. If any clutch material is past the original side of the shoe, that could be your problem. A lot of times it will fall off on its own but that depends on the aluminum in the shoe. My Mugen shoes did if pretty bad but never got to the bell. I usually run a shim between the flywheel nut and bearing to pull the bell away from the shoes a little.

If your idle doesn't sound high, then it isn't with 1.1 springs.
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Old 08-06-2010, 08:39 AM   #13
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I would say if you hit your brakes and it doesn't stall, your fine. Don't sweat it. My wheels on my truggy spin a bit too, not a big deal.
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Old 08-06-2010, 08:44 AM   #14
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Check and make sure ur carb is closing all the way when u let off the throttle.
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Old 08-06-2010, 08:54 AM   #15
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Alright i just took it apart and put it back together, i had a shim inbetween the bearing and flywheel that was causing it not to spin freely when the nut was on, i took that off and everything seems alright. (no crazy wheel spin)

When i give it throttle then let off, it seems to rev a little high for a second then go back to normal...would that be the low speed ya think Tim? And the new bearings are Avid that i'm waiting for..i bought 3 sets of them

Thanks guys i appriciate it!
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