Isolastic vibration

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I have recently rebuilt the front motor mount with new rubbers and bushings for my 74 commando. Having reshimmed and installed the mount I am feeling vibration at all revs through the foot pegs and handle bars.
The problem seems to be this. When I look at the bolt that goes through the motor mount it is not centered. It is in fact higher which means the inner 2 buffers are tight againt the inside top of the mount hence transfering vibration from the engine to the frame. The outer 2 rubbers with the steal inserts are squished down under the weight of the motor.
Either these outer rubbers are too soft or I am missing something in the set up of the motor mount. I have tried a second set of outer rubbers with no change.
Any thoughts would be appreciated.
Ross
 
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Yes. Iso gap is correct but the motor sits so low in th front mount that the outer rubbers are squashed and the inner buffers are touching the inside of the mount transfering vibration.
I'm not sure how to correct this. Has anyone had problems wit the outer rubbers with the steal inserts being too soft?
 
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The inner rubbers for some reason sound like they are too big, they should not be touching the inside of the cradle at all
until the motor is running and jumping up and down, then their function is to provide support as the outers squish.
Are the new inners the same size as the old ones you took out? Maybe you got sold an oversize batch of inners?

Can you rotate the outers 180 degrees so the mount sits more centered in the cradle?

Maybe try putting your old, properly sized, inner rubbers back in?
 

RoadScholar

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Just so you've checked.

The bolt that secures the mount to the chassis can be run in either way (in from the left, or in from the right), if you have run the bolt in from the left the washer and self locking nut will interfer with the right engine case causing the vibration you describe when the engine is running; with the engine at rest you will have a deciptively narrow clearance.

RS
 

rvich

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Are you doing the install while the bike is on the center stand?
 
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Bolt head goes in from the right side so clearence is OK. Bike is held up by a lift which supports the bottom frame tubes.
Ross
 
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