Honda Pacific Coast engine vibration

Discussion in 'Road Warriors' started by Mr. Paul, Jan 11, 2018.

  1. Mr. Paul

    Mr. Paul Adventurer

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    Hello all! I am the proud new owner of a 1990 PC800 with 40k on it. The motor seems to be vibrating more than I think it should. Can anyone tell me if this bike has any type of rubber engine insulators and if so, where can I get them?
    #1
  2. Johann

    Johann commuterus tankslapperus

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    The PC800 did use rubber mounting for the engine. The part numbers can be found here....

    https://www.partzilla.com/catalog/honda/motorcycle/1990/pc800-a-pacific-coast/frame

    Unfortunately the front mounts are listed as unavaialble (18&19), You could try David Silver to see if any are available.

    Are you sure the vibration is from the engine? Any bike with that much plastic bodywork on it can make a lot of noise if there are worn/brittle/broken grommets/fasteners where the bodywork attaches to bike.
    #2
  3. Mr. Paul

    Mr. Paul Adventurer

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    Thanks! I think I have found the front mount from a supplier in North Carolina. Can you tell me the number of the rear mounts in the schematic? Sorry but I dont know quite what I am looking at yet. I am reasonably certain it is not the body panels. Gets worse at low rpm while the engine is under load. I mostly feel it in the seat.
    #3
  4. Johann

    Johann commuterus tankslapperus

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    There are two engine mounting bolts at the back I can see, part 29. Each of those has two of these...part 12 below. There are also two used with the front mount.I don´t know whether it would be worth replacing the collars at the back at the same time (14,15,16,17). If they are solid metal and in good shape they should be reusable.

    12 RUBBER, FR. THRUST MOUNTING
    50201-KE5-000


    The same part is used on the subframe (13) as well.

    Have you tried checking the torque settings on the mounting bolts against factory specs before spending any money?



    #4
  5. Mr. Paul

    Mr. Paul Adventurer

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    I haven't checked the mounting bolts yet. Just purchased the PC800 so I am in the learning curve. I think I may rebuild the petcock, the carb, and replace the intake boots first and see if that helps smooth things out a bit. The petcock leaks and the low idle jets appear to be clogged. May as well replace the intake boots while I'm there. I am really happy to get a PC. It is a BIG upgrade from my Helix!
    #5
  6. Johann

    Johann commuterus tankslapperus

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    I think sorting the carbs out first sounds like a very good idea. including a carb balance when back together. Ditto for intake boots. If they aren´t leaking there is a thread on here somewhere about rejuvenating old boots to make them pliable again. Might be worth a go if they are still serviceable....

    http://advrider.com/index.php?threads/soften-hard-rubber.865303/
    #6
  7. Mr. Paul

    Mr. Paul Adventurer

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    Thanks for all the responses! I went ahead and ordered new boots. They were about 20 bucks plus shipping for the pair.
    #7
  8. Mr. Paul

    Mr. Paul Adventurer

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    Update; I cleaned the carb and replaced the boots. Also replaced the vacuum lines. When I balanced and adjusted the carbs, the engine smoothed out! No mounts needed! The carbs were waaay out of balance.
    #8
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  9. Mr. Paul

    Mr. Paul Adventurer

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    Sorry but I have another question. When I rebuilt my carb I noticed a large nipple on the bottom of the plastic "tree" thing. Looks like it should have a hose or something but the end is open and if I plug it, the motor stops running. Can anyone tell me what that pipe is for? I found a photo of it on another site. It is the black plastic pipe with the open end;

    http://pc800.co.uk/cgi-bin/mwf/attach_show.pl?aid=246
    #9