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Upper motor mount bushings

Discussion in 'The Garage' started by Aedan Graves, Oct 14, 2020.

  1. Aedan Graves

    Aedan Graves XS400 Member

    Hey all,

    I did a basic inspection of the bike a while ago and noticed there's not a lot of meat left on the upper motor mount bushings to the point where the engine is slanted to the right looking head on. I've look around and cant find much on them, maybe I'm using the wrong keywords?

    I'm not apposed to pouring my own poly mounts, I've been wanting to try it for a while and this seems like a small enough job to try it out on, I just don't know where to start.

    I attached a picture of the rubber I'm talking about
     

    Attached Files:

  2. amc49

    amc49 XS400 Addict

    If they happen to luck out to be the same size as shock or stabilizer bar bushings for cars you may not have to make them. Car parts stores may well have them. You can commonly use a bench grinder to shape them or shorten if you need to to fit. Correct you want to have to slightly pressfit them into place. You in no way need the 'teeth' those have either, not having them makes the rubber last longer. Use your new rubber with the old sleeves.
     
  3. Aedan Graves

    Aedan Graves XS400 Member

    I'll rundown to the store later and look! I hadn't thought to check.

    Thanks
     
  4. xschris

    xschris a lifestyle not a trend Top Contributor

    The RD400 and 350 use them also for engine dampening. They can still be had new in some RD aftermarket kits but are pricey. The rubber is molded/adhered to the metal parts so you would need to cut and or grind it off. I have seen new oem ones on ebay from time to time just use the stock part number. Those are not a solid bushing as the top mount hole doesn't always line up perfect and need a bit of free space to do so. This is why they have "teeth". Also because of the 180 degree crank the motor vibes most at the top end. These just keep it down a bit. Only on the 81-82 sohc bikes these are really needed to be a good as they can as those motors have lower rear rubber bushings and less motor to frame mounting points than the 77-80 motors.
     
  5. amc49

    amc49 XS400 Addict

    All rubber gives, and why they use it in mounts. The teeth simply allow the mount bushing to wear quicker, what lesser contact with more load per unit spread over it does. I for one will take a toothless part quicker every time, I have replaced toothed ones with solid to make improvement.

    The teeth simply make the parts cheaper, they use less material, no different from any other parts. They also install faster with less trouble when in a hurry on assembly lines, the space allows the teeth to deform to enter a hole easier, solid would snag possibly. Those things are for the company not us.

    My view anyway. Means nothing. Bevel the edge slightly of a solid bushing and use lube and they go right in. Off center in the hole? Create a pilot point bolt out of the original bolt, takes seconds on a bench grinder. Or jack motor up or pry it around to suit with other mount bolts loose. You should have no trouble getting bolts in.
     
    Last edited: Oct 15, 2020

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