Correspondence between Andy Hall and
Mark Appleton, owner and partsman, British Cycle Supply Company. 


From: Andy Hall []
Sent: Friday, January 19, 2001 10:41 AM
To: 'Wayne'
Subject: RE: Questions

Wayne, Mark,

Your info and advice is appreciated. I have stepped back a bit from having the SRM bearing job done. After having spent some time over Xmas building a crate, I found out more about how much shipping would cost, and decided against the idea. If I were still in Britain, I wouldn't hesitate, but from here, it's a bit too pricey.

Your suggestion of the Carillo rods backed up another opinion I received a few days ago, but even so, it sounds like quite a lot of cash. Instead, I think I'm going to keep things pretty much standard, and just be careful. Maybe on a future rebuild (hopefully years hence) and after a lottery win I'll think of both SRM and Carillo.

Anyway, during my restoration, there'll be some parts I'll need, and some of the business will certainly come your way.

Andy Hall

Hi Andy,

If it's all right with you, we will print this letter and the reply in the next BSAOC newsletter and also put it on the BSAOC web site. It raises a lot of good questions.

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From: Andy Hall []
Sent: Friday, January 05, 2001 1:32 PM
Subject: FW: Questions for BSA Owners Club rep

Please would you pass the following on to your BSA Owners Club representative.

I have recently joined your club, after having bought a 1969 A65L Lightning. The bike's now in about a thousand pieces in my garage, awaiting a gradual restoration.

I would be happy if you could answer a few queries.

(1) A lot of Classic Bike, CBG, TCMC articles all allude to A65's "vibrating a lot". Please would you characterize and/or opine on this. This is obviously subjective. Do they "really" vibrate a lot? Or is this just a case of "Media Madness"? How much do they vibrate compared with a standard T140V Bonneville (which I find quite acceptable, almost beneficial!)?

Is this a BSA design flaw? Wrong balance factor, or they stuck with A50 parameters on A65? Is it due to poor adjustment at BSA during manufacture? Can it be corrected by "light" dynamic balancing, or does it need a balance factor change?

They seem to vibrate at a higher frequency than Triumphs, perhaps due to their shortstroke engines producing torque at a higher RPM range. The pre-1971 models all had solid mount handlebars, unlike most Triumph twins, and the engines are solid mounted, unlike Commandos, so with a lot of metal rotating around in there, they do have more "tingle" at high speed than the competition.

Like most British bikes, they can benefit from dynamic balancing work during rebuilding if they are going to be ridden hard, but if properly tuned, timed, and tightened, vibration should be within enjoyable limits in any case. The single carb models seem to vibrate less, and the A50 models even less again. Factory balance factor is pretty good to strive for, and due to mass production may not have been consistently achieved with the normal static balancing on the assembly line.

Should I worry about it, given that I'm going to have SRM "do" the timing-side crank bearing mod, and that I'm never going to race/thrash the motor, and that I'll be putting on a 22T Gbox sprocket (as I did on T140 with good results) to have a nice 3000rpm (or whatever) at "comfortable" highway cruise?

The SRM work may be overkill, given having to ship them the entire bottom end for serious modifications. A properly set up standard engine should be satisfactory, though I would definitely install bulletproof Carrillo steel conrods with a stock RH bush as opposed to having SRM redo the RH bearing system and assemble with the stock all alloy rods, which are the REAL Achilles heel of the engine in my opinion. More bang (actually less chance of a bang) for the buck just replacing the rods with Carrillos and using the standard bush system set up to proper specs, though if price is no object, get the SRM conversion AND Carrillo rods fitted.

(2) My front forks are in poor shape, and need new stanchions (heavily rusted, ground or filed in the past) oil seals etc. When I look in the fork seal holders (97-3633?), it doesn't seem possible to replace the seal. I don't see how to get them out to replace them. They look to be fixed in, then somehow screwed together, chromed-over. There's not an obvious way that the whole thing unscrews or dismantles. Do I have to buy the whole fork seal holder, with integral seals, at 50-bucks or so each? Is there an alternative, whereby there's a different fork seal holder which is "dismantle-able". Will this fit the stanchions 97-3637 which I think I have (and need to replace)?

I trust you have the factory shop manual, and that you have verified the year of your bike by engine and frame numbers, as pre 1969 Twin forks were totally different construction that 1969/1970 type. Obviously you have already removed the seal holders from the lower legs, hopefully using the factory C spanner tool which engages in the two holes in the outer surface.
The seal must now be destroyed to remove it, generally by using a drift to collapse it and then prying it upwards. The new seal is then coated with silicone seal and drifted or pressed in using the factory drift, or a properly sized socket.

(3) On the stanchion subject, I see all sorts of prices. Some expensive ones are labelled "hard-chrome" ones, which I imagine last longer. What is your opinion? Are the ones you stock "hard" or "soft"? Or are we talking "apples and apples" here, or "apples and pears"?

In 1970 the wearing surface of the forktubes were improved by the BSA factory with a flash coating of hardchrome, but at present I am not aware of any stock British made forktubes in production for the 1969 or 1970 A50/65 models with hardchromed wearing surface, only with standard 1969 type unplated finish. The close (but not identical) 1969/70 Triumph British made forktubes are available hardchrome, but the only BSA tubes currently available with a hardchrome surface are US made chopper forktubes which can be obtained in standard length on special order, and are more expensive than the British made ones. Do they work better? About the same. I managed to destroy one of the factory hardchrome tubes on my BSA by scoring them badly with a damaged plastic damper sleeve....

(4) A reliable acquaintance recommended that instead of renewing the piston rings with BSA types, I would be better off using "Triumph-type" tapered ones. Do you recommend this?

There are better rings than original out there for performance applications, but I think you will find current manufactured British Hepolite or Japanese Cyclecraft rings that are intended specifically for the BSA to be quite adequate, and they are tapered, the top and middle rings all having a top and bottom side to them. More important is proper honing, cleaning, and lubing of the cylinder walls before assembly, and proper break-in. Do avoid Taiwanese rings. Though some very good pistons are made in that country, I have not yet seen a Taiwanese ringset I would assemble an engine with.

(5) What are your thoughts and opinions on SRM's mod? My motor is in pretty good shape, having only done a few thousand miles. It's at .020 overbore, for some past reason. Did they ever leave the factory like this?


The big-ends are just fine (I miked them still on standard dimension), but I can detect a slight slop already on the right-side plain crankshaft bearing. When I look at that puny-looking, thinnish bronze bearing, it's easy to say to yourself that they could have, and should have done a better job. I'm not sure…

Like they said in the old BSA adverts, Maseratis ran plain crank bushings.....among others! I agree a bearing would have been nicer, but think the bush has got a worse rap than it deserves, and the soft alloy conrods, which I have seen break in half, or distort at the big end, have been ignored. Don't forget, you do need some clearance in the bush- How much slop do you have? You can check with a dial indicator, and/or inside and outside mikes.

I understand perfectly how a little bit of wear starts an inexorable and irreversible deterioration, with oil pressure to the bearing and bigends, left roller bearing dropping off, and eventual catastrophic failure. I don't ever want this to happen to me, and don't want to worry about it either. (A CVMG colleague made me laugh when he told me about a friend of his who once suffered the famous "timing-side bearing blow-up" whilst riding, and suggested that BSA could well stand for "Balls-of-Steel Association"!

I would imagine what broke was the rod, not the bushing. Keep the oil clean, run the correct weight, (50 WT in the summer, 40 in the fall) warm up the bike, and run steel rods, and a well set up engine should work just fine!

So, I don't really mind spending a few hundred bucks, if I can later parade around with pride and confidence on such an otherwise-fine machine!

(6) I heard that someone else in the States also did a "bearing mod". Do you know any details, or can you make any recommendation. SRM seems to be "the guys" for this.

There was a guy called "Smitty" at a place called "Tri-City Motors", among others, who did right bearing conversions for racers, but tracking down these guys and convincing them to find the time to do the conversion for you in a timely manner may be a challenge. SRM conversions have a good reputation, but 2 way shipping and insurance and brokerage, expensive modification work, and along with the necessary conrods may be a lot of money.

(7) I plan also to put taper roller bearings in the steering head. Do you have these? SRM charges quite a bit. I have a small lathe to make up a simple collar/ring. I just have to locate some bearings which will fit in the space.

I have tried these bearings myself, and not only do they cost a lot, they are also thicker than the stock bearings, leaving a gap between the headlight brackets and the upper crown. I think now that high quality stock bearing kits are back in production in England, I will revert to them next fork rebuild on my personal bike. I think your assumption that you can make up spacers to fit a standard taper bearing to your bike are wrong, as the kits require standard bearings to be ground to fit, something that is not easily doable on your lathe and requires considerable precision.

(8) Any other things you recommend, apart from Boyer and oil filter? I want to do this motor ONCE, for all time (har...har...), not for speed/power, but for reliability and bottom-end "grunt". (I also want to be just like that guy in the 1968 BSA promotional/sales poster, surrounded by the bevy of bikini-clad babes down at the marina...)

Sure: besides Carrillo rods 71-1105/1106/A and dynamic balancing by an expert,  a high output alternator kit 331-131 and Barnett clutch plates 57-1362/A are nice. There is a ball bearing type clutch adjuster screw available (part number 57-2159/A) to convert the standard pressure plate into a bearing type one for a few bucks. When you remove and clean the sludge trap after your crank, install an allen type sludge trap plug 70-3905/A. There are high output cast iron oilpumps 71-2413 out now for your bike, but I would wait for the rotary pumps expected out next year for the ultimate oiling system. There is also a finned sump plate with magnetic drain plug available, though I use the standard type sump plate and clean it out every oilchange. By the way, you may find a 22 T gearbox sprocket 68-3089/22 a bit on the high side for gearing, and requiring grinding some alloy to install, though people do buy them. There is also an updated clutch "shock absorber centre" 57-4435 with 5/16 bolts to replace the old system that used tiny screws to secure the side plates, a good investment to prevent the slipping clutch that follows the shearing of the original screws. A heavy duty nylon lined clutch cable should finish off the job, and away you are, looking for "BSA Girls" at the marina.

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Happy Kickstarts in 2001!
Andrew J. (Andy) Hall
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