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Old 10-17-2009, 09:22 AM   #1
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Default Could it be an airleak?

I was having trouble with my engine yesterday. I started the car and it idled fine. Then after 30 seconds it would start to idle extremely high and the wheels would start moving. I put the truggy on the dirt and it moved by itself. But it cant be the idle because i turned it down and it still did it. And the carb wasnt opening either. Its an V Spec with 3 gallons on it. Not sure what could be wrong. Any suggestions?
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Old 10-17-2009, 09:45 AM   #2
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sounds like an air leak or possibly to lean on the bottom end
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Old 10-17-2009, 09:59 AM   #3
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So should i seal it up?
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Old 10-17-2009, 10:04 AM   #4
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You could try sealing it up. It may be the front bearing. They can develop air leaks after some time. May also want to check the o-rings in the hsn. Good luck.
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Old 10-17-2009, 10:12 AM   #5
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How could i find out if its the front bearing? And i would need to replace that right.
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Old 10-17-2009, 10:50 AM   #6
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Not sure how to test it but if you have ever noticed any oil residue on the front bearing or in the clutch assembly. Thats how I noticed it on my nova. I actually just got my new front bearing fro avid this morning. I guess I will tear down a couple motors today and replace the two front bearings. I got a ceramic for the nova and the bearing rbmods gave me for the xtm 457. The standard bearing is like $5 and the ceramic one I got for the nova was $10 from avid rc. I would just replace it for 5 bucks if your motor has some time on it. That way you will be sure. My nova would high idle after wot runs. I first thought about idle gap and a fat low end but after trial and error and much tuning I am pretty sure its the front bearing. I had the motor sitting on the bench for a few days without a clutch on it and noticed a little oil droplet on the bottom of the front bearing. Bam that reminded me of what Rick from rb mods said about my xtm 457 having the same problem. I hope you figure it out.
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Old 10-17-2009, 06:30 PM   #7
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If you plug the exhaust and fuel inlet port,you can blow into the carb with the engine held upright. Put a couple of drops of fuel on the bearing and you'll see it bubble up if it's a leaking. Kinda shadetree but it works
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Old 10-17-2009, 07:02 PM   #8
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i seen the same thing last week, i changed out the 2 orings 1 on the carb and other in the motor. the lower carb oring that in the carb hole, and i changed out the front bearing.
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Old 10-17-2009, 07:29 PM   #9
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Just put a new ceramic front bearing in my nova/rex p5x this evening. Took a quick pic with my phone. Its a little out of focus. The crank has rbmods signature on it and an R engraved on the con rod. Looks like quit a bit of grinding was done to the crank and sleeve. I hope the rain stops so I can burn some nitro thru it tomorrow. I also hope the bearing takes care of the suspected air leak.
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