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Valve seal Recommendation(s)

Discussion in 'Norton Commando Motorcycles (Classic)' started by RoadScholar, Oct 3, 2019.

  1. RoadScholar

    RoadScholar VIP MEMBER

    Joined:
    Dec 28, 2008
    Looking for manufacture(s) and part numbers for intake valve seals for a '71 750 with bronze guides.

    The seals that came in the "genuine gasket and seal kit" are a serious joke.

    Best.
     
  2. RoadScholar

    RoadScholar VIP MEMBER

    Joined:
    Dec 28, 2008
    I finally found the Comnoz post with the Kibblewhite part number, that was updated to 71006-4 (set of 4). For those of you that may be looking for same the site URL is: https://www.kpmi.us/

    I apologize for my lack of diligence...

    Best
     
  3. jseng1

    jseng1

    Joined:
    Nov 26, 2009
    The stock type seals work fine as long as they have the springs. But most suppliers send them out without the springs. You can get them from Old Brits (insist on the springs). Other brands with the springs do not always fit - some are too tall and strike the spring retainer.
     
  4. RoadScholar

    RoadScholar VIP MEMBER

    Joined:
    Dec 28, 2008
    The seals in the kit I purchased may have been an after thought, or knock-offs; they could be easily be installed and removed with fingers and had the flexibility of an old inner tube, I wasn't going to use them. The Kibblewhite seals have demonstrated all the right qualities and are noted by one of the best, if not the best, Norton engine builder to shed his grace on this forum. I'm sure that I could find a topic to argue with Comnoz, but it would have no Norton content.

    If I'm going to pay a top shelve price I expect the part(s) to come with an overwhelming amount of peace-of-mind. When this engine is finished I'll have the bandwidth to worry about something else.

    Thanks for the information, Fred keeps a stock of good stuff, but I'm not willing to buy it in the hope that the seals will work when I can make a similar purchase and know that they will work.
     
  5. Torontonian

    Torontonian

    Joined:
    Dec 28, 2009
    Kibblewhite seals on the intakes is the way to go. You do not really need the special tool to install them over the guides.. Just lube 'em with fine oil and use a lot of finger force and they push right down into place. Never re-use any valve seal. New only. Just my 2 cents on that. Hope this helps.
     
  6. comnoz

    comnoz VIP MEMBER

    Joined:
    Dec 10, 2008
    The viton seals get hard after some time when used at Norton head temps. They were fried after one year in my bike. 440 degrees F. max temp for viton.

    Teflon seals will handle 600 degrees F.

    A piece of tubing makes them easier to install. Just make sure the tubing is large enough that it clears the spring -after the seal is on the valve stem.
    If the spring can not expand due to the tubing it will make a hole in the seal under the spring.
     
  7. jseng1

    jseng1

    Joined:
    Nov 26, 2009
    Yes teflon seals can take more heat. But some brands of teflon seals are too tall. Most people still use the stock type seal without the spring because thats what you usually get with a cheap (paper) "genuine" gasket kit. The same stock seal will accept a spring and Fred supplies them that way. So if you're going cheap - at least get the Spring seals. If you're going quality then you shouldn't even be using a "genuine" gasket set because "genuine" original seals don't even have the springs.
     
    Last edited: Oct 5, 2019
  8. cliffa

    cliffa

    Joined:
    May 26, 2013
    Is there anywhere in Europe that stocks these? Kibblewhite are quoting (an estimated) $26 shipping which to me seems pretty expensive for what would fit in an airmail envelope.

    Cheers,

    cliffa.
     
  9. northern750

    northern750

    Joined:
    Jun 18, 2009
    The Kibblewhite seals don't appear to have springs on them, should they have springs and do they need them?
     
  10. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    They have a flat band on the lower OD at the guide and a wire coil where they contact the valve stem.
    Kibbewhite should have all their worldwide sources on the US website.


    thumbnail_Image-153.jpg
     
    Last edited: Oct 10, 2019 at 3:04 PM
  11. cliffa

    cliffa

    Joined:
    May 26, 2013
    The white PTFE 71006 have a wire spring on the seal collar, and a sprung retainer on the body. My personal opinion is that it's better to have than not have.

    Cheers,

    cliffa.
     
  12. Tornado

    Tornado VIP MEMBER

    Joined:
    Dec 5, 2017
    Wasn't there a material comparison write up done on commando seals using viton/ stock and teflons ? Was it on OldBrits or some other obscure place? I recall Kibblewhite (Viton) were found best overall.

    I got my KB from an Ebay reseller for pretty decent pricing.
     
  13. cliffa

    cliffa

    Joined:
    May 26, 2013
    :confused:
    That guide looks a bit sloppy !:D
     
  14. Time Warp

    Time Warp .......back to the 70's. VIP MEMBER

    Joined:
    Dec 3, 2012
    I bumped the clearance up to 4 mm to avoid galling. :D
     
    baz likes this.
  15. northern750

    northern750

    Joined:
    Jun 18, 2009
    I must be missing something, the Kibblewhite valve seals I see online are red with no springs. Where are the white ones with the spring and band listed?

    Thanks.
     
  16. cliffa

    cliffa

    Joined:
    May 26, 2013
    Last edited: Oct 11, 2019 at 11:31 AM

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