A65 Lightning project......

[geraldhattrick75]

Hi to everyone.
This is my first visit to this site and I have a few queries regarding a 1965 BSA A65 Lightning, but please tell me if I overdo things.

The bike is a semi built basket case with a rolling chassis  and I was told that it was a Clubman.

However, although it has siamese exhausts, a racing saddle, Ace bars, rearsets and the general parts associated with an LC, it had a single manifold head with a mikuni carb.

What information I have is that it was built in 1965 (engine number A65DC- 7144 suggests that this is correct) and was used as a factory mule, only being registered in 1970. Additional parts supplied are: a twin carb head, two Monoblocs, a rear wheel with a Dunlop  alloy rim and the original single seat and a handlebar top yoke with a raised (I think) handlebar clamp. 

Forks and front wheel will need stripping and sorting - new wheel rim will need lacing onto existing hub.

I have pretty much stripped the engine down and can confirm that clutch side it has a standard roller bearing and ball bearing on the timing side, which I believe is a mod. (pleased with that)

The cam is numbered 68- 473, which I believe is standard for a Lightning but not sure if it would be different were it a clubman.

It's had an interesting life within the factory (?) with repairs having been made to the nearside front of the barrel, and welded repairs to a raised oil gallery near the contact breakers.

I'm not overly fussed one way or the other but, is there any obvious way of telling if it is/ was a clubman? (I believe that the lubman had a close ratio box but am not sure of how that could be identified?


Anyway, the plan is to build it into a clubman look- alike, as I think they look mouth wateringly good. And reckon to take 2 1/2 years to do so.

I built a (dare I say it here?) Velocette Venom and I found that 2 1/2 years allowed me to shop around and build it to the standard that I wanted, without 'throwing money' at it. 
Well, that's the plan.

Any comments or suggestion would be gratefully received and I hope you won't mind my seeking your knowledgeable advice as the project proceeds.

Thanks,
Dave.

[geraldhattrick75]

Er, not sure if this is the correct way to add a note to my previous but:

I need a drive side main bearing- the old one is knackered. Any recommendations for a new one please (where and how much?

Incidentally, the outer is rotating slightly in the crankcase housing. Any suggestions for preventing this recurring with the new bearing please?

Many thanks,
Dave.

[chaz]

https://www.draganfly.co.uk/index.php/bsa/bsa/a50-a-a65/1965/223-crankshaft
the parts book
https://partsbooks.britishonly.com/partsbooks/20-10166C.pdf

if the clubman was race spec , chances are that the gearbox internals, gears would be different. no markings on the outside like seperate pre unit boxes would have.
unfortunately you might have a problem, the bearing outer is not supposed to rotate, it will only add more wear and make the housing bigger. options are, machine and weld a new bush in to the correct diameter or use a seal like Loctite bearing fit 641.
the outer race should be a nc3 bearing which is a tighter tolerance outside ground diameter, if a Japanes bearing was sourced chances are that it was a standard fit so may be possible to measure outside diameter and find a bigger one.

I had a customer with a square 4 motor to rebuild, he sent it for shotblasting which took the housing oversize , we had to scrap the cases and find replacements.

[geraldhattrick75]

Thanks for that Chaz, much appreciated.

I've printed the parts list- which is going to be indispensable.

While I was wearing my printer out I thought I'd print this service manual that I came across on t'internet:
https://drive.google.com/file/d/1A9-J8ctG7aYh6SgSb-IjYEXDeGPR9-qw/view

I'll get the Loctite bearing fit 641.

I just know that I'm gonna show myself up for the plonker I am but when you say "the outer race should be a nc3 bearing"  is NC3 a bearing manufacturer?
And is there a standard bearing type number for the main bearing (like 6205 and etc)

I'll get on to Draganfly tomorrow.

Again Chaz, a big thank you.

Regards,
Dave.

[Servodyne]

The correct roller bearing for the drive side is either a Hoffmann RM.11L or R & M  MRJ 1 1/8".

Both bearings should be a C3 fit. This refers to the internal clearance of the bearing and does not affect the tolerance of the outside diameter of the outer race. As a general rule, if both the outer and inner races are a tight (shrink) fit, then more internal clearance is required to prevent the rollers bearings being 'crushed' and overloaded. If the inner race is only a push on fit to the shaft, less internal clearance is required. Therefore a C1 or even a CN (starndard) bearing will be specified. The larger the C number, the greater is the internal bearing clearance. The C number is usually annotated next to the manufacturers part number as polished rings, so a C3 will have three polished rings. If there are no rings this usually means it's a standard CN fit.   

As the outer race is 'rotating slightly' in your crankcase, the amount of 'crush' will be reduced, so a bearing with less internal clearance  will be acceptable, either C2 or CN.
Loctite 641 should provide a good repair.

Hope this helps
Jim         

[JulianS]

The 1965 engine takes a ball bearing not a roller. See recent thread.

https://www.bsaownersclub.co.uk/bsaoc_forum/index.php?topic=6685.0

[Servodyne]

"clutch side it has a standard roller bearing and ball bearing on the timing side, which I believe is a mod. (pleased with that)"

It looks like it's had the timing side modification with end feed, so a roller on the drive side will be correct

[geraldhattrick75]

Thanks julian, that article really does explain a lot and extremely well and kinda shows that mine is no longer a standard 1965 model.

It has the R & M  MRJ 1 1/8" roller bearing in place (loosely) and seems to be a two piece in so far as the outer separates from the inner easily... (or is that yet another indication of how worn it is?).
No shims or washers between it and the crank face.... (original 1965 crank I guess)

It also has the ball/roller timing side bearing, which would suggest that it has had a few mods done along the way.

The engine seems to have had a bit of a rough time over the years- possibly reflecting the enthusiasm of the BSA staff in whatever role the bike might have been used. (why hunt for the correct spanner when you have a hammer and alloy welder handy?)

Pistons have a date stamp of  3/2/70 (possibly the date it left the factory (in roadworthy? condition)... It's also 1/2mm oversize (when did BSA go metric?) and marked 68/0909 (can't find that number in the spares list)....

I'll stick with the R & M  MRJ 1 1/8 bearing as suggested by Jim (it's what came/ fell out after all), and look to the C2 or CN internal clearance jobbie.

I can't thank you guys enough. This really is very educational...... And boy, I need educating.


Regards,
Dave.

[chaz]

one cause of oversize housings  (letting bearings spin) is previous owners pushing bearings in and out cold, the rule is heat the casings up until the bearing drops out, heat evenly. if done cold, it can shave or ream the bore out. my local engineer does open out bores and fit sleeves and weld in to save crankcases.

[geraldhattrick75]

one cause of oversize housings  (letting bearings spin) is previous owners pushing bearings in and out cold, the rule is heat the casings up until the bearing drops out, heat evenly. if done cold, it can shave or ream the bore out. my local engineer does open out bores and fit sleeves and weld in to save crankcases.

Thanks again Chaz.
I'm quite fortunate in as much as, although I live in a small village on the outskirts of Stafford, I have such an engineer living round the corner.
He is presently doing a bit of work on the cylinder base and bores, and a weld job on the twin carb head for me.

I'll get him to measure the bore more accurately than I can and see if it is ok for loctite-ing and fitting a new MRJ 1 1/8 (using the heating process suggested- obviously) and if not get him to carry out the work you mentioned Chaz.

Incidentally, I think I'd misunderstood the C2 etc internal clearance information- thinking it was an increase in the outer ring outside diameter rather than radial or axial clearance to allow for elastic deformation. (please tell me if I'm still being an eejit...)

Well, this project looks like taking longer than the original 2 1/2 year estimate, based on the formula of: 
Pt (Project time in years) = Ptc Project total cost / ((annual pocket money) - (Annual beer money))

But I'll enjoy doing it and learn a lot on the way.

[JulianS]

68 909 is the number of the bare piston. The number in the parts book, 68 908, is the number of the piston complete with rings pin circlips.

The bores were measure in millimeteres hence the oversize as 1/2 mm.

The date would be date of manufacture of the piston

[geraldhattrick75]

Thanks for that Julian.

Regards,
Dave.

[geraldhattrick75]

Well, having spent my money on the main bearing, a full gasket set and a set of engine/gearbox seals I am now ready for the bottom end re-build.... (I'm happy with the Big ends, timing side bearings and small ends)

I'm planning to use the twin carb head and, If I've understood the parts manual correctly, (thanks again Chaz) the valve gear that came out of the single carb head should fit the twin carb head.... Once I've fitted new valve guides. Obviously i will need to re-cut the seats and grind the valves in.

Reason for re-using the valve gear is the £200.00 cost that new set of valves would cost......

I'd greatly appreciate your thoughts on that..... please. 

Is it feasible even?   


I hope you don't mind my pestering you good folk.


Regards,
Dave

[chaz]

If I remember rightly....
the valve assemblies were the same . the Lightning had a splayed intake head for the twin carbs, the single carb version had a twin inlet manifold fed fron a single carb but straight fed not splayed although I have seen adapted home made manifolds for twin conversion.

I trust you cleaned out the sludge trap and oil ways in the crank if you are using it again??

[geraldhattrick75]

I trust you cleaned out the sludge trap and oil ways in the crank if you are using it again??

Er no.
I was going to but haven't done so.......... er, yet.

thanks for the timely reminder Chaz.