# Brute force 750 rattle



## Trxguy594 (Oct 21, 2013)

I just rebuilt my brute and all was going great. Motor sounded great. Rode for maybe 3 hours no problems. Went for a good pull after washing it up and not it has developed what I would describe as a rattling or kinda a grind. Sounds like something rubbing kinda like a chain but I put all new chains in it. Can hear it strongest by clutch side but doesn't seem to be coming from clutch area. Any pointers would be awesome and apritiated. Mostly heard at idle but comes up a little with rpms. I'm at a loss

---------- Post added at 04:21 PM ---------- Previous post was at 04:05 PM ----------

Also getting oil out of vent tube underwater pump. Could oil pump of quick working? I know that spring seal or watever could also be bad?


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## NMKawierider (Apr 11, 2009)

Let's hope its nothing internal. Might as well pull the clutch cover and pull the primary and look for any spinning on the crank and any larks on the air deflector plate behind it. Start it while its off to see if the noise is still there and if it can be located closer too.

On the oil pump shaft seal, its just a regular seal. Its the water pump seal that a mechanical seal. I assume it got replaced with the rebuild. If not...probably should have. It needs it now. If it did get replaced, look for shaft movement or excess crankcase pressure from a kinked vent line.


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## Trxguy594 (Oct 21, 2013)

Unfortunately I didn't replace oil seal and mechanical seal. I'm getting blow by out of that vent tube so I think maybe it starving top end for oil and noise is timing chain guided rubbing or cam in bearings? Could I be losing oil pressure enough from a bad seal? I will prolly look for any kinks. Oil isn't getting coolant n it tho.


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## NMKawierider (Apr 11, 2009)

The only pressure against the seal is the weight of the standing oil in the crankcase. It doesn't seal the pressure area of the pump.

Pull the valve covers and run it. You will know if its getting oil or not. Also if any of the cam sprocket bolts have come loose...you will hear it better along with any chain-related issues.


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