Valve seal Recommendation(s)

RoadScholar

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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.
 

RoadScholar

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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...

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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.
 

RoadScholar

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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.
 
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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.
 

comnoz

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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.
 
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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.
 
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cliffa

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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.
 
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The Kibblewhite seals don't appear to have springs on them, should they have springs and do they need them?
 

Time Warp

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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
 
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cliffa

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The Kibblewhite seals don't appear to have springs on them, should they have springs and do they need them?
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.
 

Tornado

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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.
 

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I bumped the clearance up to 4 mm to avoid galling. :D
 
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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.
 

cliffa

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Last edited:

cliffa

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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.
Bumping in the hope for a response.
 

cliffa

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Hi Cliffa think I've got two spare from when I did my intakes back in spring. Can send them your way if you'd like. PM your addy.
That’s great, thanks Tornado. I’ll P.M. you now.

Cheers,

cliffa.
 
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