Loud gear sound when revving?

The-DMV

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When I rev my engine, I get hear a loud gear sound that's almost louder than the actual engine. Any ideas of what it could be? Here's a video I took with my phone:

After riding for 15 minute, it seemed to get worse.
 


Frankenstein

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Do you have a spring under the clutch plate? I recognize that specific sound from when I had to fix that very sound for someone.
 

The-DMV

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Yes, there is a spring, but I notice that when I turn the crank, the clutch plate wobbles a little bit as if something is bent in there.
 

Timbone

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It COULD BE the small gear on the main crank being a bit loose and climbing up to hit the clutch cover when revved. Easy to check.
 

Street Ryderz

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When I rev my engine, I get hear a loud gear sound that's almost louder than the actual engine. Any ideas of what it could be? Here's a video I took with my phone:

After riding for 15 minute, it seemed to get worse.
Are you sure thats a gear sound because it sounds kinda like a head clearance issue and it would sound worse after running a bit and just keep getting worse!
 

Frankenstein

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Are you sure thats a gear sound because it sounds kinda like a head clearance issue and it would sound worse after running a bit and just keep getting worse!
Oh that's a real good possibility actually, especially because it gets worse with heat.

Though possibly detonation? Maybe? Kinda weird sound, that aftermarket head might be a bit too much? Running 87? Maybe give 89 or 92 a shot see if you can clear it up and get that wide Rev down a bit smaller, you'll be running a little cooler too which will help if it's just detonating.

Quick look under the head tells all...
 

The-DMV

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I'll look at the head then. That sounds like that's likely the problem. I'm currently running 91 octane fuel, and that's all I've done. If clearance is the issue, what do I do? Get a thicker head gasket?
 

The-DMV

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It COULD BE the small gear on the main crank being a bit loose and climbing up to hit the clutch cover when revved. Easy to check.
I checked that little gear, and it seems tight. There's no play in it, so I don't think that's it.
 

Frankenstein

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Yep, or add another gasket (should use 2 new ones really...)

Uh I have a question do you seem to be lacking power while riding? Could be a blown head gasket, they can be pretty loud, even a exhaust gasket pop could make a loud unusual sound that seems to be something it isn't. If while running you look closely at the head gasket area or exhaust gasket area you can see puffs of gas comming out, you can also usually feel it. Just hover fingers around the gasket areas, you will feel the puffing of the escaping gasses.

Just something to do instead of pulling the head, may actually yield a simple result.
 

The-DMV

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Okay, I'll pull it tomorrow. I don't seem to be low on power. I'm getting up to 32 mph with my 36 tooth sprocket, and I still need to tune the carb right to maybe get more out of it. The engine is still breaking in too, and I'm not seeing oil around the head or leaking out of any seals.
 
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