Valve Spring Pressures

Any one have the Vv spring pressures of a standard Commando Vv spring?
I am giving a mate a hand with his RH10 head, took the old Vv spring set out, purchased a so called original set supplied by a reputable vendor , and as a check with the old against the new, old ones went from slack to just under 1 1/4" compression and pulled up between 97 and 98 lbs on all four spring sets.
New ones pulled up 82 to 85 lbs at same compression stroke of 1 1/4" , so wont be using them!!!
Dont know the source of the old ones or their age, although outer spring wire diameter looks slightly larger on the old ones.
Forums thoughts?
Regards Mike

Not sure if this will exactly answer your question but in 2003 I measure 3 sets of new springs

Installed lenght of 1.3 "

Commando springs from Les Emery 65 - 70 lb
Aerco springs also 65 to 70 lb
Racing springs from Hemmings 115 lb

Over the nose of a PW3 cam

Commando springs from Les Emery 185 lb exhaust 200 lb inlet
Aerco springs 160 lb exhaust 170 lb inlet
Racing springs from Hemmings 225 lb exhaust 240 lb inlet

I used the Hemmings springs in my Dommie for 10 years renewed about every 3 seasons. They fell back to around 220 lb each after a few races but we never had any issues with valve bounce up to 8000 rpm on Schitsu tach recorded by onboard video

The Aerco and Emery ones coil bound at about 230 lb

The Hemmings ones at 290 lb. 60 thou off coil bind they were 240 lb but I these days I see no reason to go that high based on our results.

I always used Castrol R and covered the cam with oil poured down the push rod tunnel everytime I started if it had been parked for a week or more. I think you need to be careful if you used these sorts of pressures on the cam so take care to keep the oil in good shape

Based on my experience I see no need for more than 220 lb pressure over the nose on a Norton 500 race bike. The bigger inlet valve on a Commando might need a touch more but I doubt it.

Thanks John, yes was a bit perplexed by the difference in spring pressures.
This is for a mates bike that is quite stock standard, giving the head a clean up in the ports and tidying up the seats and Vv's.
As an aside spoke to Gerad over the weekend, his 750 going really well with a young quick rider onboard.
We discussed the fact you know him in person as I do, I know you on here!
Regards Mike

From some old notes, I have the stock (Aerco) Commando springs, with 1.321" installed height, having 65 lbs. on the seat and 170 lbs. at .450" lift.

Ken

Here's a recent inquiry I made: standard-750-valve-spring-info-t22819.html

Mark

Hi Mike

So you know Gerad ! Brave man

I have known him for nearly 40 years now since university days. He was I think, the first president of the Victoria University Motorcycle club, now the Victoria club, which became one of the top clubs in NZ.

Very nice guy - if a little crazy - like all of us !!! Tried to Skype him at the weekend and talked to his wife who said he was away racing.

We may meet in a year or so. I have been away overseas working for my retirement - which should involve a bike or two. But next year will be 6 years and that's just about enough I think so I should be home for good next Oct I hope.

Cheers John

Ok John, thanks for that, I will see him at Manfield this coming weekend.

Am trying to talk him into one of Jim Comstocks crank case reed Vv's to stop his leaks, the cases he is running right now doesnt have that 1 1/2 " opening behind the smaller sump plug though.
See you next year
Regards Mike