I ordered new valve springs on the internet.
After receiving, I checked those springs with the spring cups belonging to the cylinder head. The top cups fitted fine, but the bottom cups seemed to small (about 0,5 mm) with the outer springs partly resting on the edges of the bottom spring cups. No problems with the inner springs.
After measured the old springs I noticed that the top and bottom also differ by 0,5 mm. Another difference is that the old ones seems progressively wound and the new ones are not.
Two possibilities: 1) in time they become compressed in diameter at the bottom or 2) the springs have to be a bit smaller at the bottom to fit the bottom cups .

If option two is the correct one, I have to order new ones.
Is anyone familiar with this problem?

After watching another thread, I think from Allen?
You might want to mic the diameter of the wire used on your old ones, then the new ones, and see if they are really close or the same diameter?

Whoever it was, they had coil binding, and I think damage occured???

_I've_ certainly become concerned! I'm building 3-4 A65's, and 3 A10's...
Brett

Hi,

Cant comment on tapered springs, but I had problems with some unbranded valve springs. Probably an eBay purchase. My experience was that the coils bound and ultimately (I believe) wrecked my cam.

See these threads http://www.britbike.com/forums/ubbthread...5864#Post275864

http://www.britbike.com/forums/ubbthread...1981#Post281981

I now believe the wrecked cam was from coil bound springs. To get the bike back on the road I recycled the old original springs and the motor was a bit tired even with the megacycle cam. I did myself a favour and bought springs from EdV. They are strong, but not enough tension to accelerate wear and nowhere near coil bound. Transformed the top end performance. Really, for what you get the small amount extra paid is excellent value.

Cheers
Ray

When the bottom cups are in the cylinder head, one might not noticed the difference in size, but I had them out and compared the fitting of the old and new ones.
Possibly no one does that and it might be no problem.

The wire of the old ones (about 4mm) is slightly thinner than the the new ones (about 4,15mm). On a caliper hard to see, with a mic difficult to measure precisely by the curvature.
The length of the new outer springs are 46 mm. manual says 44-45mm, but that should not be a problem (I think).
They were no cheap ones and I have no problem even to pay a bit more, but in that case I like to be sure that the newer ones do not appear to have the same measures. That would be spilled money.

Did have a look on EdV site (if E & V Engineering is the same) , but only found Triumph and Harley springs and no mention of fitting a BSA A65.
I have no need for extra strong springs, just standard will do, but will have a look again.
Thanks

Hi Go2fer,

Yes, you got the site correct. A lot of Ed's stuff is not listed and you just need to email and ask. I have no need for extra strong springs either. Just it's apparent some springs will coil bind more readily than others. The story is from the posts I've seen here is the EdV ones are the least likely to coil-bind. I needed new springs anyway, so for me the little extra was insurance. I had a motorcycle head specialist set it up for me as Ed had specified installed heights. IIRC he checked the spring tension (right term) and it was up there but not crazy. Just checked my notes 80lbs at no lift.

If you are using the ones you've bought I'd suggest checking how close to coil bound they are when fitted and at maximum lift. That's when my problem was readily apparent. For example, 0.15 mm x ??8 coils = 1.2mm = 0.048" less potential valve lift by my crude reckoning. Also your new ones if an extra mm longer may have to cram more metal into the same space (depending on the pitch / number of coils??).

I found Ed extremely helpful and he gave me some valuable advice on other aspects of what I was doing (some very mild port cleanup that the head guy also did) along with selling me some nice black diamond valves.

Cheers
Ray

Thanks. The effect of the extra height + the extra thickness of the wire, that"s I what I forgot to take in account.
I hoped that I could do the job with standard parts and no extra help from a technician. When I have to take in account specified install heights (in stead of just slipping the correct springs into place), that might exceed my skills.

BTW my technical English is not as it should be, so I am not quite sure what coil-bind means. Is that the situation that the bindings of the spring meets each other and there is no (or to little) room to compress anymore?

Yes.

I'm no genius. My dad was a car mechanic and I learnt a lot helping him when I was a kid. I've learnt a hell of a lot more since frequenting this site. Especially about the 'correct' way of doing things reltive to our bikes. My first mistake was lashings of oil on the pistons when I put new rings in. That wasnt the dumbest thing I've done either.

Good luck with it. Just work through it carefully and you will get answers to any questions here.

Cheers

Following the rebuild of my A65 engine last year, I had a couple of issues with a pushrods snapping/bending. After investigation it turned out that the valve springs were becoming coil bound and although the engine could be kicked over and started, the stress on the pushrods was too much and they failed after a few miles of riding.

When I checked the outer valve springs the wire was 4mm in diameter which was just a bit too thick and caused the springs to become coil bound.

I managed to source a new set of valve springs from SRM here in the UK and these springs have a wire diameter of 3.2mm, thereby avoiding the previous problems under full compression.

I dont know why the first set of springs didnt work properly, they were bought from a BSA supplier and I assumed they would be OK.