Help - Same motor noise lower crankase side!!

5 replies to this topic
  • nopremix

Posted April 14, 2002 - 08:50 AM


I just got done replacing the cb drive gear key ( made one myself to make sure it's real tight), because the replacement I got from yamaha seemed to have the same amount of play as the one I took out. I still have the same noise.

This time while it was running, I put a mechanics stethoscope on it. I heard these sounds coming from these specific places on the crankcase side moving from the head down it gets louder and louder:

Head -- sounded normal

Cylinder -- more noise than the head

Kick starter shaft area -- about the same as cylinder

Clutch Cover -- a little more noise than cylinder

Below kick shaft area close to bottom -- quite a bit of noise

Below water pump -also- down by oil pump drive -- the loudest noise

I still wonder if it could be excessive play in some of the drive gears behind the clutch basket ( not the clutch basket gears). These gears seem to have a lot of play on their shafts when I inspected them. Also I wonder if anyone has had issues with the oil pump area. When I spun the oil pump drive gear by hand it did not have any rough spots I could notice like a bad bearing would.

Any suggestions would be extremely helpful at this point, I am at a total loss.

  • nopremix

Posted April 15, 2002 - 06:07 AM


no one has any ideas on this one?

  • John_Lorenz

Posted April 15, 2002 - 07:23 AM


what about the impeler on the water pump ?

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  • Shawn_Mc

Posted April 15, 2002 - 08:10 AM


Check the impeller like Ego suggested. IF thats ok, go back to your CB keyway. Another guy posted that he got a piece of 5mm key way from McMaster Carr. He also said he had to fit the key by sanding very carefully. I did the same, no more problems as of yet. If going with a piece of 5mm stock, Id freeze the key and heat the crank and the gear and see if you can assemble it without reducing the keystock. If your bike is 01 or later, you dont have a keyway so look elsewhere for your noise.

  • nopremix

Posted April 15, 2002 - 09:09 PM


What do you guys suggest looking for with regard to the water pump impeller? That is easy enough to look at, I just don't know if there is something specific to look for on it.

  • John_Lorenz

Posted April 15, 2002 - 09:25 PM


If you remove the case from it and clean it up spin the thing around listen for Bearing noise.. Loose, cracks, damage etc etc

Shawn your turn

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