Author Topic: Valve Springs...stiffness?  (Read 850 times)

Offline AndyDenmark

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Valve Springs...stiffness?
« on: 30.09. 2014 07:17 »
Hello all

I have recently had newvalve springs put in my Golden Flash and the mechanic concerned, who is a good one , seems to theink they are too " stiiff " as the bike in his opinion should not be as noisy as it is in that area. Are there different types and quality of springs.

Many Thanks in advance.

Andy

Online muskrat

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Re: Valve Springs...stiffness?
« Reply #1 on: 30.09. 2014 10:51 »
G'day Andy. Most new vehicles have a lot lighter springs due to modern cam designs/lighter valves. Yes our springs are quite heavy in comparison. It has got me thinking has anyone measured the spring tension in our springs? I did 20 years ago but that book got eaten by white ants along with the bottom step. *pull hair out*
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Offline Briz

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Re: Valve Springs...stiffness?
« Reply #2 on: 30.09. 2014 11:30 »
I'm not sure why stiffer valve springs would cause more noise. But they definitely increase cam & follower wear.
I once put S&W springs meant for a triumph in an A10. The cam & followers were shot inside 3000 miles.
The beehive springs we used in the salt-flats bike have an installed rate of 90-lbs. No Idea what standard is I'm afraid.

Offline AndyDenmark

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Re: Valve Springs...stiffness?
« Reply #3 on: 30.09. 2014 16:08 »
Thanks guys. I have spoken to SRM in the U.K who did not supply the springs fitted :) and the guy there says it sounds a bit like a slightly longer spring was sent in error as evidently some models do have different length springs...have ordered a new set that will be fitted while I am away at sea and will see if that improves the noise issue. It was only because the mechanic and one or two others commented on the fact that the iron head Golden Flashes should be a bit quieter up top than mine . She is running very well but the noise issue is a bit of a concern :).

Online Billybream

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Re: Valve Springs...stiffness?
« Reply #4 on: 01.10. 2014 07:55 »
The Haynes manual quotes all models have same springs:-
Free length inner = 1" 17/32
Free length outer = 1" 7/8
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Online trevinoz

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Re: Valve Springs...stiffness?
« Reply #5 on: 01.10. 2014 21:59 »
Rockets have different springs.

Offline wardleybob

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Re: Valve Springs...stiffness?
« Reply #6 on: 02.10. 2014 17:02 »
Super rocket springs are 2 00 & 2  1/8 long and can get coil bound on a flash.

Offline RichardL

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Re: Valve Springs...stiffness?
« Reply #7 on: 02.10. 2014 17:30 »
I had a recollection of reading the force constant somewhere, but now can find nothing on it other than lengths. If someone had an NOS set of springs, a test could be run to know what BSA had designed, or stumbled on. I believe spring equations have been around since the 1700s or earlier, so I gotta think BSA had engineers interested in that, even if not overly concerned. One of the books I have says, "valve springs are cheap, so they should always be replaced in an engine rebuild." Maybe so, but force constants in new product could vary widely from original or between suppliers, even if the dimensional characteristics match.

On another side of this, what about the beehive style springs? Does anyone know if they are available for an A10? Are they better than originals when used on an A10? What do you do with the bees? Have I beaten-up this topic enough?

Richard L.
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