Monthly Archives: February 2018

Building a Rotating Motorcycle Engine Stand


Since time immemorial, I have stripped and built engines on the bench or on the floor…

…and it’s a royal pain in the backside. Trying to balance the thing at suitable angles, hefting it about, running out of hands at every turn and of course, that searing pain when you realize which part of your anatomy it was resting on when you hit it.

But no more, I say! Rupert Ratio has a drawing for a decent one, which you can lay on its side, in the back of his book.
Before embarking on production I had a quick look at fleabay (it’s often cheaper to buy than build) where I saw a truly snazzy one which rotated through about 300 degrees.
On closer inspection, it had a couple of drawbacks. One was a fairly substantial price tag and the other that the rotation was locked by a bolt through a radial slot in a circular plate. This means that only the friction applied by the bolt would be holding it, which just didn’t sound quite enough when you start riving on the thing with a big bar, or even have to tap something off/out.

However, this is the backyard builder and suitably inspired I headed for my various scrap bins to see what I could find…

I have to confess that I bought some bits. Actually two steel discs (offcuts on fleabay, presumably out of the middle of something with a hole in) and two M10 nuts and bolts.

To action!

The steel discs were marked out thus…


For marking out rough stuff I love my little white paint pen. It’s nowhere near as accurate as engineers blue and a scriber, but a lot less messy.

Then bolted together, stuck in a vice and attacked with an angle grinder.


A chunk of square section provided the next bits. Chopped up and drilled as below…20171007_123626

A quick zap with the welder renders all the nuts captive… then the channels get glued to the discs



Now I need something to hold them off the ground…
I cadged half a dozen four meter lengths of this heavy walled tube from some chaps who were chucking it in a skip. It used to be handrail in an industrial unit. Keeping your eyes open and have a bit of cheek can save you a fortune.


But beware, welding galvanized steel produces lethal fumes. I make sure I grind all the zinc off the outside and since I don’t have an enclosed space to weld in I reckon being a bit careful will do for the bit on the inside. You may want to clean that off too.

Once it was tacked together I chopped it in half…


Because, by a fortuitous miracle I just happened to have a few yards of this size tube as well


Which is what I’d call dead jammy.

So, with a couple more bits stuck on, I now have an adjustable width standy uppy bit, to stick my roundy roundy bits to.


Now, if you’re going to build one of these, I suggest you ignore the next bit, because it’s where I came up with a stupidly complex solution to a very simple problem.

I bolted the disk to the upright, so far so good…


Then produced this natty little pawl mechanism, involving lots of cutting and folding, which I welded to the top of the pole.


And it works a treat. BUT…

If I’d just left the pole a bit longer (like I did on the other end) it would have been a helluva lot simpler…


To just stick the pawl in a slot in the pole. Then fashion a little spring out of piano wire to hold it in place.


But only put a spring on one end, or you’ll need three hands to rotate the engine!¬



A few bits of plate cut out and bent, provide the right mountings for the engine. Which just bolt to the captive nuts in the channels on the discs.
The width is adjustable anyway, But I measured the ones on the bike to get the right range. The height difference I took from RRs drawing, but isn’t critical.

I also decided that it would be a good test bed for the paint I’d decided to use on the B40s frame. So a coat of etch primer and a splash over finished the job.


One huge, and unforeseen, advantage of the two part construction turned out to be the incredible ease of mounting the engine. You never have to actually lift it up. Just tilt it back to put the front in…


Then swing the back up and slide the other end in place


In use, I have to say it’s wonderful. Not that mine’s any better than anyone elses’, but having one is wonderful. I don’t know how I ever lived without one.
It seems to be stable at any angle and has handled sockets with a big breaker bar and some genteel tapping with no problem whatsoever.
I’d definitely recommend the extra effort of the rotating mechanism. It ain’t difficult and being able to instantly set it to just the right angle to reach bits (or stop them falling out) is a real boon. It’s odd, but it’s one of those things I probably wouldn’t bother to adjust if I had to take a spanner to it, but it makes life so much easier.


BSA B40 Rebuild, Order of Play, Getting Ready

It’s well worth scribbling up a list of everything you can think of well before you start on the job. You will, of course, miss some bits, but it will nonetheless give you an opportunity to come up with a rough order of play, based on which items are likely to be long lead, need saving up for or, of course, need something else doing first.

I stuck it all on a spreadsheet, which makes it easy to add the bits I forgot and indulge in the unmitigated pleasure of ticking things off when they’re done.
For those who are sad enough to be interested, here’s the logic behind my particular approach. It may or may not work for you, but that’s your decision.

Stripping the top end of the engine may seem like a very odd place to start, but there is logic to it.
Firstly, it allows me to assess the state of the cylinder bore. This is important because knowing whether I need to have it re-bored (one of the few jobs I can’t sensibly do myself) and by how much, will determine which piston I need to buy.
I’ve already decided to fit the high compression SS90 piston, but do I want it standard, or oversize and by how much? Once I know that I can buy the piston and once I have that I can send it off to get the re-bore.
Incidentally, if someone says they don’t need the piston to do the re-bore, go somewhere else. A proper job involves machining to precisely the right piston clearance, not just an arbitrary plus 20, or whatever.

The other thing I can check is the big end wear. Alas, on the B40, a crankshaft rebuild is another one of the few jobs I can’t do. The crank is a press fit job and the combination of extreme force (typically seven tonnes or so) and precision needed to dismantle and re-assemble it requires a big hydraulic press and a lot of skill. Not to mention the fine art of truing and balancing it, so it’s a job for the professionals. That’s professional engineers, not smoothly dressed gentlemen with hot 1970s Fords and guns. I used to really enjoy that show.
However, dragging the ageing mind back to the matter in hand, it’ll make a big difference to the cost too. Quite apart from the cost of the crank rebuild, I may well then be tempted to fit a needle roller big end in place of the original plain bearing.
I’m not sure on that one. On the one hand, Jeff Smith got to second in the world championships on plain bearings and this will be a relatively low stress, low mileage road bike, on the other, I’ve no idea how often his engine was rebuilt and I want this bike to comfortably out last me. More thought required.

Having stripped the top end, reason dictates that I continue the engine strip. Again, there is logic. A very major factor here is clearing the bench space. I have only one small bench and as long as there’s half an engine sat on it I can’t use it for anything else. It’ll also give me a fair idea of what else I need to buy for it. B40 bits (especially tuning parts) are not always easy to come by, so having a shopping list to hand aids regular browsing of the web, autojumbles and any passing fellow enthusiasts. All of these will probably need to be enlisted at some point.
As an interesting (well, to me anyway) aside, it seems far easier to get BSA parts in the USA than it does here. I’m really not sure why, but beware import duty and the (sometimes higher) “administration fee” that the post office put on collecting it, when calculating prices.

Once the engine is safely packed away in bags and boxes (more on that later) I shall turn my attention to the front wheel, the reason for this is that I have managed to acquire a seven inch twin leading shoe brake which, while not correct for the Enduro or Trials spec’, is much a much better stopper than the SLS original.

According to the all-knowing RR (Rupert Ratio aka Dave Smith) it will fit in a B40, but may need some material removing to avoid interference with the fork leg. Since that’s all RR said on the matter, I have no idea how much or from where, so quickly fitting it, while I still have the forks assembled will enable me to quantify the job, or come up with plan B if it doesn’t work.

Sticking with the theme of long lead items, wheels come next.
The front will definitely require a new rim, since I’ve decided to fit a 21” in place of the original 18”. The enduro actually had a 20” front wheel, but good tyres in that size are few and far between, so most restorers opt for either a 19” or 21”. I’ll go into the reasons for my choice when I get to wheel building.

I’m not too sure of the condition of the rear rim, but the fact that it’s been painted over doesn’t lead me to suspect that it’s pristine. I’ll probably want to replace the spokes with stainless ones anyway and I’ll certainly have to dismantle it to refurb the hub, so that needs to come apart as well. Then I can order rim(s) and spokes.

Once those few bits are out of the way the strip of the cycle parts should be pretty straight forward.

I’ll need to check the state of the swinging arm bushes early, as this is the other job that I can’t do. It requires putting the whole frame in a big press to either remove or fit the swinging arm pin. My impression riding the bike home when I bought it (about 50 miles) was that it was actually in pretty fine fettle, the handling felt surprisingly tight and stable, but it needs to be checked properly. Casting about on the web I was surprised to find that leaving it in doesn’t seem to provide any barrier to cleaning or painting the frame. Indeed quite a few people have had the frame powder coated with the swinging arm in place. I’d have expected the heat/grease to cause some problems.

It has probably not escaped the notice of the more astute reader that I will rapidly end up with a large pile of bits, which need to be stored carefully and somewhere near sensibly, for a period of at least twice the estimated duration of the build!

In my case this is exacerbated by the fact that I don’t have a nice, dry, heated garage. Indeed, I’m still building in a tent. It’s a bigger tent than it was in the days of Little Suzi, but still a tent, I did invest in a tiny shed (3x4ft) for storage.

My suggestion of the basic requirements, when dismantling are as follows:-

Large and small Freezer Bags – the ziplock type work best and can accommodate parts up to cylinder head size.

Sharpie Marker – For writing on the freezer bags. You will definitely forget what some bits are (or which versions , if you’ve bought used replacements) and it’s really helpful to write on what sort of order they assemble in i.e. where spacers go and such.

Takeaway boxes – For small parts, or groups of small parts, cylinder head fastenings for example. One can of course buy lots of takeaways, but if you don’t want to risk your health, fifty new ones is only a few quid on the internet.

Big plastic storage boxes – the stacking type are good. Cheap from places like Willco and QD. You can put the freezer bags and takeaway boxes in them.

Mobile phone – PHOTOGRAPH EVERYTHING before you take it off. Digital photography is wonderfully free, so don’t skimp. Back up your pictures in the cloud (also free) and you have a secure record of what went where.

Vacuum cleaner – With a bit of imagination and some gaffer tape, you can suck the air out of the freezer bags and effectively vacuum pack your bits to stave off oxidation.

Silica gel packs – also available cheaply on the web. Stuff them in your freezer bags to keep the moisture at bay.

Tie on labels – old fashioned, but still the best way to label some parts.

All that may sound a bit anal, but it’ll add about twenty quid to your rebuild cost (unless you buy a vacuum cleaner specifically for the purpose) and could save you hours of work, and possibly some expensive bits, later on. In the words of the great Eric Burden (obscure 1967 song reference, just humour me) “it will be worth it”

Clean or grubby?
Personally, I prefer to clean off the very worst of the muck, just to make them easier to handle, but leave the parts pretty much as they came off the bike until I need them.
At build time it’s nice to pull out lots of clean and shiny bits, but clean parts are a lot less stable than mucky parts, by which I mean that newly cleaned surfaces are open to oxidation and scuffing, far more than those protected by a layer of grime.

To take this to it’s logical conclusion, try cleaning a cast iron part. I boiled my barrel (is it just me or does that sound like a Glaswegian insult.. “g’away and boil yer barrel, pal”) in caustic soda and it, literally, rusted faster than I could paint it.

The counter argument is that it’s not until a part is cleaned that one can properly assess its condition and consequently, whether a replacement needs to be sourced.

I suggest use of that wonderful oxymoron “common sense”. The barrel, for example, had to be measured accurately to resolve the rebore question, so that had to be cleaned straight away. The cylinder head isn’t going to be attacked straight away, so that can stay grubby for now.

Just remember that if you do clean something, figure out how you’re going to protect it first. In the case of the barrel, Granvilles cylinder black on the outside, WD40 on the bore and gasket faces and vacuum packed with silica gel.

BSA B40 Rebuild. What and Why – Restoration, Rebuild or Reboot?


It’s surprisingly easy, in any project, to lose track of exactly what you’re doing and why. In industry it’s called “scope creep”, can cost millions and is controlled by having a tightly written specification and referring back to it at regular intervals, so that any change must be justified.

In bike building terms it’s a bit simpler, but it’s still a good idea to at least have a decent mental picture of your original objective.

When developing said picture one would be well advised to be both honest and unembarrassed. The latter is a lot to do with remembering that it’s your bike and you can do what you want with it. Someone somewhere will probably disapprove, but that’s their problem, not yours.

By way of explanation, here’s my logic.

I want an enduro style road bike. In all honesty, it probably won’t do the bit of green laning that we all say it will, since I already have a trials bike. It really is just a style/fun thing.

It won’t be my daily commuter, so it will probably be fairly low mileage and it’s unlikely to be thrashed.

I want something middle weight, to me that’s about 350cc.

I want another British bike, rather than a rice burner. Just because I like them.

It must be a practical ride on modern roads.
Now this is a potentially contentious one. I’ve read many an article by people who insist that their bog standard classic Brit is perfectly practical and I think they’re wrong. I say this, not as someone who thinks of brit bikes as some sort of ancient novelty and was brought up on Hondas. My first bike was a C15, followed by a 500 Ariel single. But that was forty something years ago and the roads were very different.

Sure, old bikes are fine for a Sunday run in the country with a few mates on similar bikes and in all honesty, this isn’t intended as a daily commuter, but I still don’t want to think twice about going anywhere on it. So here are my requirements for modern roads, and why.

Mirrors and indicators – Sorry, but the sheer volume of traffic nowadays means you need mirrors. Obviously anachronistic as they may be if you look behind you often enough to keep track of modern traffic, you’re not looking forward enough.

Nobody is looking for hand signals nowadays and, ugly as indicators may look, trying to signal right while your speed decays on a busy dual carriageway, just ain’t safe.

It must not be embarrassed on the motorway – I don’t intend to do a whole lot of motorway cruising on it, but you only have to get two miles outside any given town and you’re likely to be on at least a hefty dual carriageway. Even on A and B roads the traffic moves a lot faster than it did in 1962.

So the B40 is going to need a bit more power. I’m not talking about tuning it to death or trying to blow off anybody’s Kawazoomie, but a bit more would be good.

It must have decent lights – that means they must illuminate more than the front mudguard.

The brakes must have a significant effect on the speed of the bike – again, modern traffic moves a lot faster than it did forty years ago and drivers expect you to be able to stop, so they won’t allow you extra space to scrape off your speed with the soles of your boots.

It must go when I want it to – yes, old bikes will always need more maintenance than modern ones, but I don’t want to have to fiddle it into life every time I go out on it.

So that’s the requirements. How am I going to meet them with a B40?

On the styling side, I’m going to rebuild it as somewhere between the Enduro Star and the C15T (trials). Actually the Enduro Star didn’t exist until a couple of years after mine was built (and had a different frame) but the high compression piston and slightly hotter cam (used on the Enduro Star and SS90) will give it the gentle power boost that I’m looking for.

The C15T was made at the same time and had the same styling but was a 250. Both had a wide ratio gearbox that wasn’t too great for pure road use, so it’ll retain the stock gears.

So you can think of the result as an “in the style of enduro”.


The Enduro Star


The C15T

There are some out there who will consider this a terrible waste of a standard bike, and it’s a fair point. As it happens, standard B40s are still pretty common and I always hated the styling.

As I already mentioned, my first bike was a C15, which looked identical to the B40. At the time it was just an old bike and what I really wanted was a Bonnie café racer. Try as I might, I could never get the C15 to look like anything but the type of bike that peoples dads went fishing on and that feeling has stuck with me through the years.

Of course, the purists will tell me to go and buy an Enduro Star. Alas they’re usually kept on the shelf between the hens teeth and the rocking horse poo, a fact which is firmly reflected in the price.

Strangely, nobody seems to complain when people take standard Ford Escorts and build Mexico copies, or even rebuild A65s as Rocket Gold Star copies for that matter. Each to his own and all that.

So, the power part is pretty much taken care of by the SS90 piston and camshaft. It’ll also get a little bit of extra boost (along with improved starting and reliability) by the addition of electronic ignition and a modern carburettor. The former being completely invisible and the latter pretty discrete.
12v electrics and a low power/high output LED headlight bulb take care of illumination, again pretty much invisible until you switch the lights on.

Braking needs a bit of compromise. I suppose one could fit modern forks and a disk brake (enough of the “pre65” trials community seem to want to) but, frankly, that would be losing quite a lot of its fundamental B40ness. I’m planning to fit a ’67 twin leading shoe brake, doing a proper job of arcing the linings and using some of the clever modern lining materials. That should be enough to cope.

All that covers one area of the project specification. The other two factors are time and cost.
Time is pretty fluid. I don’t have, anything that could be described as a deadline, though I do get terribly impatient when a new project is on the go and I have got an urge to do a 1200 mile bike rally in July this year, so now I’m in a hurry already..

Cost is a different matter. I’ve got a sort of a budget in mind, but it’s not set in stone. Unlike Little Suzi, this is not intended to be a shoe string job, so I’ll invest enough to do the job right. At the other end of the scale it’s not a money no object job either.

To try and make some sort of sense of that, bits that need replacing will be replaced. All the simple bushes and bearings will get done, but some of the most expensive stuff will only be done if needs to be. Parts will be picked to be fit for purpose. No cheap rubbish, but not necessarily the Rolls Royce option either. I’m not going to spend a fortune building a full race engine for a genteel road bike, or leave knackered old shocks in it to save a couple of quid. Back to that common sense stuff, really.

The Backyard Builder’s Back with a BSA B40

What-Ho, readers old and new. Well, the clue is in the title really. Speaking of which, my apologies to people suffering from Bells Palsy and Rowan Atkinson impersonators. Or Rowan Atkinson, I suppose.
Anyway, I’m back, with a new project.  Actually there have been a few in between.  There was the  SV650/Minitwin  track day bike, that convinced me I would never be a racer.  There was starting out in trials, which convinced me just how unfit I am, then the switch to the much more serene and safe world of pre ’65 trials (on a lovely little Cub) and the consequent shoulder injury that I’m still recovering from six months later.  Not to mention the road bikes of course. So I won’t.

However, to the point.  I recently became the proud owner of a 1962 BSA B40 (350 single, basically an over inflated C15) in running order, with a week and a half’s MOT left on it and, slightly bizarrely, a 1964 age related registration, despite what look like matching frame and engine numbers.
I say running order, it did actually run and handle, quite nicely.  The brakes were a bit scary (or have I just got used to modern ones) and when I stopped half way home it did produce a sizeable cloud of smoke/oil mist.  But I’m pretty sure that was just because the cover for the hole to access the clutch cable was missing.
Any BSA historians out there may well have just thought “hang on, the ’62 B40 didn’t have a hole to access the clutch cable” and, in truth, neither did the C15 from which the outer timing cover that was fitted to it was nicked…    until somebody hacked one out of it.
To be fair that (though true) probably casts it in a bad light.  It’s actually a pretty good (if not pretty) little bike.

And I have plans for it!  As ever, some will hate them and some may even love them, but the process  (despite the feedback suggesting title changes such as “Boring old Pillock” (which doesn’t even alliterate) or “Bodging B*stard”  (with which it’s hard to argue) will be documented and explained here.
Having said that, I lay no claim to knowledge, expertise, skill or wisdom in matters motorcycle, so take my scribblings as they stand and keep the salt handy.

For those who remember Little Suzi, my operating conditions have improved greatly.   I now have a  bigger tent!