Hi guys
I've just ordered hepolite valve springs for my bsa a65 1966
They are supposed to be 1966 onward but the springs outer diameter is bigger than the spring cups , my head No is 68-0915 so any clue to what's going on
Mark
Morning Mark,
I have just bought some new springs from SRM and they fitted fine but by how much are your springs too big? There is an interesting 'read' on the Classic British Spares web-site re A65 valve springs that might help.
Dave.
Hi,
There are 3 different inner and 4 different outer springs sizes for the A65 over the years, you could have any combination of these. There are also different heads, I think you quoted the casting number not the part number. Let me know what model you have and I can let you know the head part number for your year.
As Dave mentions, SRM are the best stop for springs they will fit, with the correct amount of coils and apply the right seat pressure.
https://www.classicbritishspares.com/blogs/news/replacement-bsa-a50-a65-valve-springs-1962-1972?_pos=1&_sid=750b59bf2&_ss=r
I would send them back for a refund.
Best wishes...
Bought a Hepolite set from Feked based on the bike's age and they were spot on if that helps
Hi
The springs aren't too big so was thinking of machining a slight taper just to locate, the inner spring is ok fits good
The bike is supposed to Be a 1966 65 engine but has been butchered a bit, that number was the only number I could find stamped on the head
Hi,
Without a model I can't give you a head part number.
Before you alter the springs. If they are the wrong length or wire diameter they might become coil bond or offer the wrong spring pressure causing the valves to bounce.
I have this info if it helps:
From my records 1965/66 part number, inner 68-0169 could be offered as 1 21/32", or BSA manual 1 5/8" and SRM 1 19/32" long with a 2.7mm wire. Diameter 0.898mm.
Outer 68-0475, 2 1/16", BSA manual 2 1/32"and SRM 1 21/32" 3.8mm wire. Diameter 1.233
Best wishes...
The head is from a 1967 Spitfire - casting 68 915 but the machined part 68 914. Not in the 1967 parts book but a new item which came on parts bulletin GA22 which ammended the parts book.
Hi Julian,
That makes sense, in 1967 the springs changed to part number outer 68-0805, inner 68-0806.
Best wishes...
Thanks I'll measure the old / new springs . The model is a65L 1966
But not sure what a spitfire head make any difference . The spring do say 66 onwards so should still fit According to hepolite
Hi,
As Julian has discovered you have a 1967 Spitfire head whereas you were expecting 1966 Lightning.
There are different springs and cup specifications you should have 68-0805, 68-0806 with cups 68-0166, 41-0026.
In 1968 the outer spring changed to 68-0930 and to 71-222 in 1971, the inner spring changed to 71-1177 in 1970. Unfortunately the manufactures are producing generic springs which are causing an issues.
I would guess others have experienced the same problems, I did so made a spreadsheet of information to help in the future. I don't claim its fully correct, however for 1966 the spring inner length is 1 13/32" 3.1mm wire. The outer length 1 27/32" 4.2 mm wire, SRM offer 1 21/32" long with a 3.8mm wire and 1.233" diameter.
I have the German made spring specification mentioned in the classic bike tech report but that needs alteration to fit.
Hope this helps, best wishes...
Cheers everyone
Burton bike bits responded to my question as I got the springs from them, they said it's a spitfire head 1968 and I have a 1970 a65 as well with head 68-0466 which she said is a 1965 , hell of a mix up , so if I want to get a 1970 head what casting number should I look for
Sorry to be a pain
Mark
Wouldn't it be cheaper just to buy springs to suit your cylinder head. When they went to using the finned rocker cover the head and cover were about 1/4 inch wider.
Hi,
The head for a 1970 Lightning is 68-879 so the casting is 1 number different.
A 1965 head was held down by 2 rear 68-338 5/16" bsf EN14B bolts, the 1970 head is held down by 2 rear 68-337 3/8" bsf EN14B bolts. Worth checking what head and barrel you have, the barrel can be altered if need-be.
The head studs changed when the rocker cover had fixings for a head steady. The bikes were fitted with a plain cover from the onset, the finned introduced in 1966 and the finned with steady started in 1971.
Best wishes...
Just run a clearance drill down the back two bolt holes. There is plenty of meat on the head. I did this some years ago on a friends Lightning which was a mix and match. He's had no problems with it.
Yes the barrel is the 3/8 hold down / my frame is a 69 so I don't suppose the head makes much difference but will check the clearance for rear 3/8 hold down bolts
Ok measured springs
New ones large one L -1"27/32 coil dia 4.02mm 6 coils
Smaller spring L- 1"7/16. Coil dia 2.97mm coils 5
Old worn ones outer spring L- 1"3/4 coil dia 4.03 6 coils
Smaller L- 1"19/32 coil dia 2.62 mm coil 5
Head hold down bolts all 5/16 but the barrel is 3/8 bsf so either find a newer head for my 1970 engine coz the inlets are 1-5/16 not 30mm
My spitfire head I'm presuming can be used on either my 1966 or my 1970 engine is this correct as I've fitted new guides and valves to that one already
:) :) :)
I've done that on a couple of heads. There is actually a service sheet that gives the correct sizes etc. I think Julian posted it here about three years ago.
Mike 8) 8) 8)
Hi,
The Spitfire head had 2 inlet sizes, 1 5/32" and 32mm.
Best wishes...