KR double springs info

Racing K Models

KR double springs info

Postby thefrenchowl » Sat Jan 20, 2018 6:47 pm

Hi Kurt,

As requested:

Image

Image

Patrick
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Re: KR double springs info

Postby EKHKHK56 » Sat Jan 20, 2018 7:16 pm

Love that image Patrick! From deep somewhere...And the XLR base nut is my favorite.
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Re: KR double springs info

Postby hennesse » Sat Jan 20, 2018 11:52 pm

Patrick,

Thanks for posting this. I've got the double valve spring setup on my 1954 KH, along with KR #7 heads, and a set of KR cams from the early 1960s. I'm restoring the bike, but I'm gonna keep these racing parts on it to make the previous owner happy - and heck, it makes the bike a little peppier than the production configuration. (Dock me some points, you AMCA devils, I don't care).

Do you know when the #7 heads came out?

Dave
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Re: KR double springs info

Postby thefrenchowl » Sun Jan 21, 2018 6:05 am

#7 are the last ones for flat K/KH type pistons, so, 1967/1968... But not much different from the outside...

Check on your KH cylinders that they have been properly releived for the double springs behind the exhaust valves, the std casting is in the way there due to the valve tilt and bigger diameter covers.
Recheck as well if you have the proper valve opened to head clearances to take full advantage of KR heads and cams.
Cylinders should also have the valves sunk as per factory drawings

Patrick
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Re: KR double springs info

Postby hennesse » Wed Jul 18, 2018 7:19 pm

Attn: French Owl, wz507, and other racers...

I badly need a set of the KR double valve springs. I saw a very old (2011) topic - on CAI about this - featuring French Owl and wz507. There was some mention of these being Triumph 500cc springs. Can you elaborate? If so, where might I find some?

What other choices do I have, while keeping the double-spring covers? Are the Enfield Racing WR heavy valves a good choice?

---
HELP! I was within striking distance of having this 4-year project on the road this summer, but lately it's One step forward, and Two steps back. I seem to have recently acquired the Midas touch - everything I touch turns into a muffler...
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Re: KR double springs info

Postby thefrenchowl » Fri Jul 20, 2018 12:21 pm

Yes Dave,

When Tom Sifton did the 1st ever set of double springs for Joe Leonard KR in 1954, he used Triumph 500 twin springs, and adapted the cam flanks to suit with his strobe light jig. Tom noticed the heavy std KR springs have plenty of rate but were too sensitive to harmonics/float at various revs of the KR 7000+ range...

Then the factory followed his path a year later and sourced similar double springs in the States...

A friend of mine thought the Triumph race were well overpriced in GB and sourced similar double springs with near identical dimms and rates from old racing Mini Cooper spares... I think a full set of 4 in/4 exh were about $50.00...

They are now in his WL/KH special and work fine, plus a spare set in the garage...

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Re: KR double springs info

Postby hugoct » Fri Jul 20, 2018 12:50 pm

If those springs would have been from a 500 Triumph they would be pre unit and the same as the 650 Triumph. I would think that RD or Kibblewhite springs for pre unit Triumph twins would work. Both JOMO and TRICOR (the US Triumph distributors) used S&W springs in their race bikes. Spring rate, diameter, length and length at coil bind would be important. You might inquire regarding the new beehive springs.
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Re: KR double springs info

Postby Mutt » Fri Jul 20, 2018 2:30 pm

who sells the new beehive springs?
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Re: KR double springs info

Postby hugoct » Fri Jul 20, 2018 4:56 pm

Try RD Spring or Kibblewhite.
You will need diameter, spring rate, free length, compressed length, cam lift.
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Re: KR double springs info

Postby Mutt » Fri Jul 20, 2018 5:20 pm

so these would all be one-off sets of springs?
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