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transmission noise

X1R9734

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New to the Forum and find it very helpful.
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Just putting the finishing touches on cb750k5 with 20,000 miles and hearing transmission noise in neutral but drastically decreases
when clutch is pulled in. Rode it for 5 minutes appeared fine except for the noise heard at idle . Using Castrol 10w40 oil examined the clutch plates and they appeared clean and fine. Before I tear down the unit what should I look for as far as bearings or anything external.
thanks
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As far as the noise in neutral with clutch out they all do that, Even My 95 goldwing had the noise in neutral until I engaged the clutch, From the dealer new They assured Me it was normal when I took it back and complained about it 50,000 miles later no problems. Don,t worry about it unless it starts making noise while riding.
 
I put it on the center stand and into first gear and the noise is still apparent. I will use it for a couple of days and see if anything changes.
 
You will get noise running it free wheeling on the center stand alot of parts back lashing in there including the primary chain.
 
Some noise is acceptable but loud is not. If an erratic come and go type then look at the carb sync, uneven idle pulses will rattle any looseness, the pulses can come from one cylinder not putting out as much as the others too like a compression issue.

More even rolling noise then look at end clearances of parts like thrust surfaces there. Shaft endplay getting looser makes more noise from what would otherwise be lower noise, the 'hammer effect' of more clearance.
 
Agreed on doing a carb sync first, along with checking general engine tuneup and engine compression. Also do a timing chain adjustment. A too low of idle speed will also make it worse. These motors do have a fair amount of mechanical noise too them because of the design. If the noise continues after doing the checks and adjustments then it is more than likely the primary chains gettin slack in them. With 20,000 miles they will be getting loose as they started making the noise with under 10,000 miles when the bikes are new. Its very hard to say if your noise is acceptable or excessive without being able to stand next to it.
 
I put in primary chain too then rethought that as I'm not that much knowledgeable about the SOHC I removed it. The DOHCs DEFINITELY can rattle at the primary chain and lower idle since they are kept taut by oil pressure lets the chain fall slack as the pressure drops off.
 
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