Valve spring options

So I have decided that I will just raid the rockers out of my RH4 for the FA head as it was rebuilt only 3000 miles ago which in turn, leaves me with a decision.
What valve train
Stock I can get complete aprox $230AU w/kibblewhite valves
Kibblewhite light racing springs + kibblewhite valves $340AU
JS beehive complete $445 (aprox $500AU)

anyone had experience with all three?
What are the advantages over stock keeping in mind I ain't no Doug McRae or Kenny Cummings
Just a daily rider looking for optimum performance.

I and others can tell ya that stock valve kit will loose control of valves cutting power drive with horrific noise and misfires too dam soon after 7000 rpm, which in street use, say to finish a tight pass in time it so easy to do in a passing gear. If kicking up heel on stock kit then invest in rev limiter security. Kenny Dreer about 20 yr ago worked up a K/W kit that Peel got the last of from him then accidentally tested fine way over redline so sticking with it. I was both pleased and horrified valve train didn't miss a beat while missing pistons. On the other hand a plain stock Commando is hard to beat up to 90's mph but then beating up rest of engine to press faster. To make use of the beehives ya need to get more radial with the cam and that may need more CR to use in towns.

A club president once told me never use more spring tension than you need. it only wears out the cam faster. If you didn't float the valves in your past experience, you don 't need more tension.

I would assume that more tension in the valve train would transfer to another area such as cam lobes or rockers, followers etcetera but the JS street kit gives the same valve tension as stock (or so I'm led to believe) thus negating that as an issue. The kibblewhite racing valve springs appear to have a higher tension load (the JS kit can be adjusted to higher load by fitting thicker washers) however I don't know if this is overkill.
I have run my stock setup to 7000rpm once or twice and beyond when I popped a gear (1st) but generally speaking I pull up at a little over 6000rpm due to the benefits of exceeding this rpm not outweighing the cons.
With the FA head I believe there will be benefits from 1000 to 7000rpm

Dkt26 said:

I would assume that more tension in the valve train would transfer to another area such as cam lobes or rockers, followers etcetera but the JS street kit gives the same valve tension as stock (or so I'm led to believe) thus negating that as an issue. The kibblewhite racing valve springs appear to have a higher tension load (the JS kit can be adjusted to higher load by fitting thicker washers) however I don't know if this is overkill.
I have run my stock setup to 7000rpm once or twice and beyond when I popped a gear (1st) but generally speaking I pull up at a little over 6000rpm due to the benefits of exceeding this rpm not outweighing the cons.
With the FA head I believe there will be benefits from 1000 to 7000rpm

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If 6000 is your general max rpm, you don't need higher rate springs. Stay with stock. Including up to PW3 cams for which the suppliers recommend stock anyway (yes I know others disagree). If you find that your new FA head turns you into a 7000 plus regular...not likely...then uprate them....

But if you plan to do higher mileages, then consider the already mentioned potential extra valve train wear with a spring of a higher rate than needed. More money now may just mean even more oney later.

Since I expect to spend a lot of time (racetrack) at or above 7000, I have chosen uprated springs, some very knowledgeable individuals suggest I don't need to, others insist I do, I am listening to both sides....but spending more money now and assuming even more later... :?

Horses for courses.

I raced mine for years with a 4S cam then an Axtell cam using standard valve springs. No problems at all. I then fitted a PW3 and put the bike on the road and suddenly I have bent valves!
the guy who has the head and hopefully has fixed it recommended the Kibblewhite lightweight racing valve springs and retainers.

If I had a standard cam I would be perfectly happy with standard springs.

Engine is currently stock w/20thou stock hepolites.
If it's overkill then that's what I wanted to know. I don't sit on 6500 rpm but would like to nudge 7000 with confidence but then, what about the alloy rods? Upgrading or over engineering one component is truly a slippery slope. It can just transfere the issue to the next component in the line then nek minnut I will need to upgrade the crank to billet with Maney cases.
Alright bit extreme but you get the point.

Is it overkill to fit up rated system and will the expense justify itself?
I am leaning toward the beehive setup and have looked at countless videos and read up but is it a tangible benignity to fit them to my daily rider that i do like to wind out each gear? Sometimes I don't get out of 2nd gear on my way to work.

My personal leaning is that the Beehive becomes useful if revving above 7500, by reducing vave train weight.

The medium cost Kibblewhite seems like a good choice for occasional 7000, if you want a 'comfort factor', standard is not a bad choice either...

Can you explain comfort factor Steve? Comfort in the hip pocket or something else?
Like I say, I don't sit on 6500 like Doug or Kenny but like to "peak" my gear changes. Local guy here in aus with a British bike shop says I looking at overkill and that the standard setup is what he used on his race bike. He ain't no Steve Maney or Doug McRae but then neither am I!!!

Like others here, I also raced for a couple years with stock valve springs with no issues. That was with a stock cam. I never experienced valve float, but I used 7000 rpm as a red line, and pretty much never ran it above 7200 rpm. When I connected with Axtell and started running his cams, I used S&W valve springs at his recommendation. Those same springs are now available through RD springs, and I use their springs with titanium retainers. I also used the Kibblewhite springs for a while with the aluminum retainers that they supplied, back before they offered the Ti retainers. They worked well, but I did have one of their springs break, so went back to RD. Haven't tried the beehives yet, but I plan to try them in the 1007 motor with radical cam for Bonneville. The key with any of them, stock included, is to make sure that they are shimmed to the proper height, typically to higher pressure for race use than for street, but staying short of coil bind by a reasonable margin.

Ken

Dkt26 said:

Can you explain comfort factor Steve? Comfort in the hip pocket or something else?
Like I say, I don't sit on 6500 like Doug or Kenny but like to "peak" my gear changes. Local guy here in aus with a British bike shop says I looking at overkill and that the standard setup is what he used on his race bike. He ain't no Steve Maney or Doug McRae but then neither am I!!!

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I like Ken's post. He is pretty much saying...'standard springs will be fine'.

I don't think you application needs anything other than standard springs for your application. Unless you have a radical cam in there, and possibly even if you do, you can run standard springs at the revs you plan to use. But you may not feel 'comfortable' with that, yes bottom line this is financial comfort, you may feel you are dealing better with the risk of a problem by spending the money on tricker parts to save the trick part you already have.

I used S&W back in the day too, in an 850 with a 4S like cam, and reangled big inlets, big ports, 36mm Amals.....and one of the springs broke...just an inner spring, the bike would not rev past 6,200 in top...until I changed them for more of the same and it went back up to 6,800.....the rev limiting factor was not the springs.

My short stroke will rev more, in my application the Beehives seem like a good idea, for my comfort, at least one view says standard would be fine in that, others might go with RD, or Kibblewhite!

The thing about valve springs is, you can fit springs with the correct seat pressure for your needs now and a year from now have lost much of the seat pressure. The springs from RD maintain their pressure over the years very well.
I don't know about the various no name springs supplied by the Norton suppliers, but the Vincent Spares Company springs appear to be made of mush.
This was discovered some years ago after a rebuilt and nicely broken in Black Shadow would not top the ton. Spring seat pressure, which had been measured at 110 pounds at time of rebuild, was checked and found to be down in the 55 to 60 pound range, after just four thousand miles.
A call to RD was made, drawings sent and new RD custom springs were made. With the RD springs installed and no other changes the bike now ran easily past the ton, all the way to 120 mph, as it should. Years and many thousands of miles later, it was still capable of 120 MPH.
Since RD springs are available for the Norton, I would use them, their metallurgy is right. But as others have said, no need for an extra high seat pressure if you are doing normal road riding, just as long as the spring is made right so that it maintains the correct pressure over many miles. RD know how to do this.

Glen

It ain't the valve springs that limit using mild red zone regularly its the cast iron flywheel brittleness and crank flex on bearings/cases. With head apart its a not a bad thing to lighten the ends of the rocker arms, especially the very ends both for less mass for springs to move but also allows pushrods to slip in and out on first attempts. If keeping the cast iron grenade and cam similar to 2S I'd use the stock springs and spend the difference on getting them cryo tempered along with lifters and cam shaft. You can lighten the factory lifters a bit also to ease stock valve springs job into factory crank shaft danger zone. I'm with Alan/acetrel on gearing up final drive to get more acceleration time in lower gears and definitely the taller 850 2nd > so good up to ~90 in mid 7000's. Its a treat to zoom up to 120+ and sustain it in nice opens for as long as you like below red zone. 3rd gear is still too tall over 850 2nd so rpms drop below max torque too much, so i tend to short shift 3rd to get the stronger/longer pull of 4th. Might consider lower 3rd ratio good to 115 mph below red zone. TC and P11 desert racers got away with factory internals [lightened cast iron cranks though] up above 8000 routinely, though not much more. 120 mph is getting into tuck down zone to faster and very rarely will even the elites sports bikers willing to exceed that in public on fun roads. Ms Peel in her hay day had standard 28.5 mm 'low' CR head + 2S cam, single 34 miki carb 2>1>mega and would out drag sports bikes up to 90 because they'd wheelie on less acceleration than a lower Cdo which surprised me too. Peel had lightened smaller OD steel flywheel though and re-enforced stress riser eliminated cases plus cryo tempered parts. Within two seasons word got out about the Norton Nut in Kingston so folks from out of state would hunt me down to compare pecking order with but with the isolastics+tri-links and spunk of Combat they didn't stand a chance in any leaning conditions. On my pure factory Combat its gets real spunky after 90 mph in 4th with 19T sprocket so have to use discipline not to hit 120 into red zone, though have tested it that hi half dozen times to get it out of my system for the long term on mere factory engine. If I feel bad to the bone my Trixie Combat can match SV650 till 70-80 then can leave it behind, but not in serious corner loads as not a tri-linked wonder that just don't have to slow up much or any at all for turns everyone else is hard on brakes, including my handy torquey boney 70 hp/365 lb SV with supsension upgrades and pure race tires wearing down to the very edges. Loss of mass pays back a lot on a Commando too but costs as much as fancy race power items.

I believe that lowering spring pressures gives a whole range of benefits, not just preventing high rpm float.

Admittedly I've only tested my JS beehive springs to approx. 6200 so far, but so far so good.

And they are shimmed lighter than suggested, even for road use. Its an experiment I confess, I'll let y'all know how things proceed as revs rise.

Just to throw a contrarian view on the whole idea of using the lightest spring pressure possible, which was my rule until recently, here is the view of John Mcdougall, ex Daytona Norton racer (1970s) , an excellent Vincent and Norton engine rebuilder . When you see a group of twenty Vincents at a North American Rally, chances are John has rebuilt 18 of them and the two that won't start and leak oil profusely are about to be rebuilt by him.
He feels that it is better to put a little extra seat pressure in place at time of rebuild. One reason is that even very good springs such as R&D will lose a little seat pressure over time and with a lot of use.
The other is that he has seen great cam and follower damage and also valve and piston tangling from rebuilders using soft seat pressures in an attempt to increase valve train life.
He explained what happens at high RPM with a too soft spring. The cam lobe comes around very fast and accelerates the follower and pushrod upward, the rocker rocks and the valve accelerates downward. If the spring is too soft, the whole entourage moves more than the can lobe lift, loses contact with the cam surface then slams back down on it a fraction of a second later, over and over again many times. This kind of impact hammer like process is much more damaging than having stronger spring which keep the all of the valve train parts in contact with one another, even at the higher end of the rpm scale used.
So where the generally accepted installed seat pressure is 85 to 90 lbs valve closed, he goes for 110 standard engines, 120 is the bike is going to be ridden very hard or raced.
Not sure what Commando seat pressure norms are, but likely similar?
I'm talking about conventional springs here, beehive is another thing again.
Glen

worntorn said:

So where the generally accepted installed seat pressure is 85 to 90 lbs valve closed, he goes for 110 standard engines, 120 is the bike is going to be ridden very hard or raced.
Not sure what Commando seat pressure norms are, but likely similar?
I'm talking about conventional springs here, beehive is another thing again.
Glen

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The specs I send out for street bikes would also give the beehive springs about 90 lbs on the seat. The racing specs are of course higher.

Thanks fellas, all great info and points of view. Much appreciated. I feel now that I have more to think about though!!

Given that spring fatigue is a consideration, has anyone any experience with retesting? I mean, longer term testing of how the spring retain their pressure with the beehive and kibblewhite?

It would be good to have a race spec head albeit detuned a bit for the street. That way the head will follow me anywhere and be suitable for any application.

worntorn said:

Just to throw a contrarian view on the whole idea of using the lightest spring pressure possible, which was my rule until recently, here is the view of John Mcdougall, ex Daytona Norton racer (1970s) , an excellent Vincent and Norton engine rebuilder . When you see a group of twenty Vincents at a North American Rally, chances are John has rebuilt 18 of them and the two that won't start and leak oil profusely are about to be rebuilt by him.
He feels that it is better to put a little extra seat pressure in place at time of rebuild. One reason is that even very good springs such as R&D will lose a little seat pressure over time and with a lot of use.
The other is that he has seen great cam and follower damage and also valve and piston tangling from rebuilders using soft seat pressures in an attempt to increase valve train life.
He explained what happens at high RPM with a too soft spring. The cam lobe comes around very fast and accelerates the follower and pushrod upward, the rocker rocks and the valve accelerates downward. If the spring is too soft, the whole entourage moves more than the can lobe lift, loses contact with the cam surface then slams back down on it a fraction of a second later, over and over again many times. This kind of impact hammer like process is much more damaging than having stronger spring which keep the all of the valve train parts in contact with one another, even at the higher end of the rpm scale used.
So where the generally accepted installed seat pressure is 85 to 90 lbs valve closed, he goes for 110 standard engines, 120 is the bike is going to be ridden very hard or raced.
Not sure what Commando seat pressure norms are, but likely similar?
I'm talking about conventional springs here, beehive is another thing again.
Glen

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Not disagreeing with anything said above, but in my opinion, a beehive spring represents a superior solution to controlling valve motion for several reasons.

1. A beehive spring is progressive (non-linear with respect to deflection), i.e., the spring rate increases with increasing deflection, whereas the spring rate of a conventional spring is fixed.
2. Beehives are used as a single spring, which is generally lighter weight than multiple conventional springs.
3. Due to their non-linear response of rate to deflection (myriad rates in a single spring) and their use of ovate wire, beehives are less sensitive to valve train resonant frequencies (causing spring surge) than are conventional springs.

Because the beehive spring stiffens with deflection, through careful spring selection the end user can obtain the best of both worlds, i.e., the spring set-up can be as gentle as desired on the seated valve and throughout some fraction of valve lift occurring on the cam flank, yet on the cam nose the pressure can be significantly higher than would occur with a conventional spring. This addresses the shortcoming Glen mentioned above (lack of valve control on the cam nose), but without increasing seat pressure.

To visualize the above, see the plot below that shows deflection vs spring force for a variety of a beehive springs. Note how the springs stiffen to varying degrees with increasing deflection. These springs are not representative of a spring appropriate for a Norton (actually for a high lift Vincent cam), but rather are offered simply to show the non-linear response of spring force to displacement for beehive springs, and the variations possible that allow the end user to select the spring characteristics suitable for their specific application.

DKT - More food for thought as you toss around the subject of upgrading your Norton valve train.