Oil leak from recently restored 72 CT70 HK1

Discussion in 'Tech Area' started by Swede, Dec 2, 2010.

  1. Swede

    Swede New Member

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    New to this forum. I am the original owner of a Candy Ruby Red 1972 CT70HK1. Just had it restored, with a new 88 cc kit installed. Had the work done by a custom shop and it looks great. Here's the problem, and I'm not sure about the part names so please forgive. After getting it home and taking it for a short drive around the block, I noticed a serious oil leak coming from the right side of the engine. Tracked it down to leakage from under the clutch housing cover. Took that off, took off a small plate and got a pin out of the clutch linkage and slid that to the right. There I found a small O ring seal that didn't seem to be seated properly at the top. This O ring surrounds what I would call a clutch button. Re-seated it, put more oil in, started it up and still noticed oil leaking from the bottom of the seal. Should this have any leak at all? The seal or O ring does not look damaged. How can I stop this leak?

    Regards,
    Swede
     
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  3. mrichard

    mrichard Member

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    Take it back and have THEM repair their problem.
     
  4. OLD CT

    OLD CT Well-Known Member

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    sounds like a nice bike!and a easy fix!the seal is shot.it should not leak.order one from the vendor of your choice.it can be removed very easily with a little pick.put a little grease on the new one before installing the new one.
     
  5. Swede

    Swede New Member

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    The restorer is several hundred miles away, or I would. Regarding grease on the seal/O ring, when I removed it I noticed in the recess behind it a small slot on the left side where the oil seems to be coming from. Is that supposed to be like that? Also, what kind of grease is recommended and should care be used to keep the grease away from the button that pushes when the clutch is engaged, or does that not matter? FYI there was no grease on the seal/O-ring when I removed it.

    Swede
     
  6. OLD CT

    OLD CT Well-Known Member

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    The little slot behind it is normal,any grease will do.you dont need alot.the old seal wouldnt have left over grease from 40 years ago.it just helps to install it.
     
  7. racerx

    racerx Administrator
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    This is the main juction of the oiling circuit; filtered oil flows out from the oil spinner (pocket inside the clutch face, behind the throwout bearing) into a channel inside the clutch cover, which routes oil to the head. The clutch lifter (stovepipe hat-shaped piece) needs 360-degree contact with the seal lip. Otherwise, pressurized oil gets past the seal - leakage you now have. The seal, PN 91201-035-010 is still available new for less than 5 bucks. The shop should be willing to send you a new seal, almost certain to cure the problem.
     
  8. OLD CT

    OLD CT Well-Known Member

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    i can give a scenario why its leaking,the builder fail to change it and with a freshly rebuilt motor with every other seal changed,''i assume''. it, the engine.obviously now has a higher oil pressure forcing oil out of the weakest link.the missed lifter seal.sound about right?
     
    #7 OLD CT, Dec 3, 2010
    Last edited: Dec 3, 2010
  9. racerx

    racerx Administrator
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    No argument here. I agree with you, fwiw. The builder probably sourced a gasket & seal kit, or "complete" seal kit alone, that lacked the clutch lifter seal and simply overlooked the arthritic original.
     
  10. Swede

    Swede New Member

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    Got a replacement seal (a different manufacturer) from the retoration shop and verified they had installed a new one originally. It seems the one they installed may have been sitting in stock for a while and lost some of it's flexability. The seal which failed has the markings NOK in a diamond with SC 12 21 4. The new seal which I installed per the above instructions is marked ADK 12 21. The new seal stopped the leak totally. The new seal also seems to have more of a rubber feel to it while the original seems less pliable. I guess some dealers or parts houses keep these things in stock for a long time.

    Now, I just have to work on getting the bike to run a little smoother. It was tuned at around sea level elevation and I am at 5500 altitude with just a little thinner air.

    Regards,
    Swede
     
  11. racerx

    racerx Administrator
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    Good to know that it was just an honest oversight and you have the leak fixed.

    Between jet needle clip positions and the pilot air bleed screw (idle mixture) screw, you should have enough adjustment range to compensate for the altitude change. I'd start out by raising the jet needle clip 2 positions and turning the pilot air bleed screw 1/2 turn counterclockwise. That will lean-out the mixture significantly. You'll have to experiment, with the engine at full operating temperature, to get the settings optimal. Hopefully my suggested starting point will have you headed in the right direction.
     

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