Friday, December 31, 2010

How did this happen?!

I never used to like rigid bikes. I've never had one either, this is (or rather will be) my first.
Some of the guys from my club have hardtail bikes and I have ridden those a couple of times.

Slowly the appeal of a stripped-down, light, nimble bike with a strong vintage flair revealed itself to me and there was no going back.
I toyed with the idea of a 1200 twin-spark Sportster chop for a while (we had an engine in the workshop that eventually went into a tarmac-ripping beast another friend built) but that just didn't happen.

Then another friend from the club decided to sell his BSA café racer and everything that came with it and I was lucky enough to snatch that at the time.

I kept it for a few years, used it as a bar hopper, went on rallies, on long trips, had fun with it and then sold it on to another friend. What's that got to do with this you say?
Well, amongst the things I got when I bought that bike (a small box of spares, the aluminium tank, the shorter seat, etc.) was an A50 engine, which I kept.
It seemed almost natural to plan a hardtail bike with that engine, although at first I had imagined a Rickman-Métisse bike,

or possibly a special built around an ACME trackmaster frame.
That wasn't really going to happen though, for various reasons, so the A50 got put on the back burner.
Then the whole chopper thing resurfaced and with it came thoughts of wild summer rides, sleeping under the stars, going on a big trip with a small bike and with all your gear in a roll-up strapped to a sissybar.
I had the engine. I had the handlebar, the mufflers and a carburetter. This thing was practically building itself!
That was it, time to decide on one thing: it would be a rigid/hardtail framed BSA.
Then came the dozens of variations on every component and trying to decide the overall look I liked best. Since there is more than one type that I really like, that was always going to be difficult and it is possible that this bike's shape will evolve.
I realised that what I liked best in terms of proportions and stance was an original front loop from, say, a Triumph Daytona or a Bonneville, with a straight-to-axle style hardtail bolted on.
The reason for this preference is probably down to a single photograph in a book called
"hot rods and pin-ups" by David Perry of an orange 1970 TR6 hardtail.

I can honestly say there was very little I didn't like about that bike and out of the multitude of looks and parts I had seen, this was one of the most coherent and well put together.
I thought I could get a Triumph front frame (and I had even sourced one locally, though it was pretty badly mangled) but there were never any guarantees it would fit.
Not being the most skilled guy out there I wasn't sure what would have gone into modifying a frame and making it so that everything could line up correctly (sprockets and chain for one).
After the local Triumph front loop turned out to be too dodgy I started looking at
British-only as a possible source of frame + bolt-on hardtail. Having bought spares from them in the past I'm pretty sure they would have been able to deliver.
But then something else happened that I hadn't thought possible in the first place. There was a frame that was exactly what I was looking for. At just the right time. Uncanny.
Lowbrow Customs. No introductions necessary (unless you've been living in another dimension where there are no cool rides, in which case please go check them out right now:
And sure enough in their stock they had a variety of complete frames as well as bolt-on/weld-on hardtails for Triumph and BSA. They've since expanded their range and if what you're after is a tidy little chop with a proper frame, they have what you need.
The best part was, there was a complete frame (all welded, no bolt-on parts) for the A50 engine (or "motor" as they say over there). Score! and you could have it in lots of flavours too: from standard wheelbase up to six inches longer at the back.
From standard height to 2.5in lower. With or without a battery base, with a looped or straight-to-axle rear end. That means something like four dozen frames to choose from just for your particular engine!
So you can imagine that just choosing the specs for the frame took some thinking. In the end the winner was:
4in stretch, with battery base, 1in drop and with straight rails. Phew.

Over to David Bird who actually makes the frames and is clearly very talented at what he does.
Both him and the guys at Lowbrow were incredibly quick in getting everything (it wasn't just the frame I got from them...) packed and shipped over to Rome.
I like the fact that this frame has already travelled more than 5,000 miles... I got some catching up to do!

Thursday, December 30, 2010


So, yes it's going to have a battery, because although you can run these bikes without one (assuming your alternator, capacitor and wiring in general are in *perfect* shape), I think, why not make life a little easier?
I've salvaged a pretty compact sealed battery off my dad's Yamaha TDM850 (destroyed in an accident thanks to some coked-up whore on her cell-phone), rather than a standard acid type, as they can be bulky and need a bit more maintenance.
I should be able to hook up one of them fancy modern chargers to it pretty easily without having to take it out of the frame or leave any connector leads behind.

These are a good idea, they work very well and I recommend you get one if you don't already have one.
I'll need to cover up the battery somehow though, because it is fugly. Perhaps some sort of battery box that could also house the Boyer Powerbox and any other avionics I want out of sight.
Note the greasy thumb-print in the first photo. Nice.

Monday, December 27, 2010


The valve cover on my engine is the late finned type found on most A50/A65 bikes. The first ones were smooth and I've always liked the look of those, so when I found this on e-Bay for a decent price I decided to get it:
It's in good shape overall, it just has a slight scratch but I'm sure that'll come out with polishing.
That's right, polishing.
I've already given it a good clean, scrubbed off the old gasket and it's looking good. It will look great when it's polished to a shiny, mirror finish.

Thursday, December 23, 2010

A place to call home.

I think it's fair to say that anyone of us who's into the British motorcycle thing would love a place like this to just disappear into and get on with it, without the rest of the world to get in the way.
Get lost in the details, look at every little thing and be there.

Wednesday, December 22, 2010

Parts: engine.

Tuesday, December 21, 2010

Parts: clutch.

Monday, December 20, 2010

Sunday, December 19, 2010

Saturday, December 18, 2010

Parts: footrests.

Friday, December 17, 2010

Thursday, December 16, 2010

Wednesday, December 15, 2010

Parts: forks.

Tuesday, December 14, 2010

Parts: manifold.

Sunday, December 12, 2010

Parts: cables.

Saturday, December 11, 2010


I have a reader from Croatia, hi!

The best laid plans of mice.

It's not a bad idea to have a build plan and at the same time make peace with the fact that you'll probably have to adapt and change several times along the way.
So far, this is my plan:

first, the rear wheel hub and brake plate get sandblasted, I can then assemble the brake, replace the bearings and spacer in the hub and then hand it all over to Peppe (he already has rim, spokes and nipples at the workshop) so he can actually build the wheel. I'll need to start thinking about getting tire and tube pretty frakking soon.
Next we'll focus on the front end. The fork has to be cleaned and overhauled, the yokes will be marginally cleaned but not overly polished.
At that point I can open up the front brake and check everything is in good condition (and actually, you know, there). We might decide to change the front tire if by this point I've gotten around to getting the new ones.
After the front and rear cycle parts are assembled and put aside we'll finish the engine rebuild.
Once the engine is complete we'll fit the frame over it sideways, then lift it up straight, insert the steering stem with the entire front end (the top yoke will lock it all in place and will already have the handlebar fully assembled) and finally the rear wheel. It's possible that it will be easier to leave the front wheel aside until the fork is fully bolted on the frame.
This will give us a free-rolling bike that can easily be moved in and out of the workshop depending on what needs to be done. One critical component to be added at this point is the side stand!
I'll bolt it down nice and tight for now, but when the frame is eventually painted and the bike is assembled again (after the mock-up phase) I might decide to weld it or tack it in place to make it more secure. We'll see about that.
Anyway, now that the bike moves on its own wheels we can tackle other, trickier components. The area to focus on is where the oil tank will go and then the mudguard. The oil tank is fairly straightforward in that all it needs is an extra mounting brace to be welded to the frame.

The mudguard needs to be positioned correctly in relation to several different points: the rear tip's position, the radius of the tire, the distance from the tire, etc.
It will need a pair of struts to support it at the back (these will be easy to take off and replace with a sissy bar when I need to carry some luggage) and some sort of attachment points at the front, underneath the oil tank area.
After all of that is taken care of - and believe me this will be one of the toughest jobs on the whole build - we can figure out how to mount the footrests and the rear brake pedal, the main caveat being the exhaust pipes. I reckon the footrests are going to be a total pain: I not only need to figure out which ones will fit, but they will also need a lot of welding to find their place on the bike.
Then comes the battery box, which will also house the Powerbox. This will be the start of the electrics/avionics chapter. We need to figure out where and how to mount the coil (ideally a single Dyna-type coil with twin leads) as well as the ignition module for the Boyer (this will probably fit under the fuel tank).
The final layer to be assembled is the top one, namely the fuel tank and the seat. The latter is a relatively simple matter, which involves welding a hinge to the rear of the frame's backbone and, crucially, two bungs (get these from Lowbrow)on the short crossmember between the rear top rails.

These provide an attachment point for the seat springs and must be properly positioned so the springs aren't subject to any lateral stress.
Fitting jobs such as the oil tank and mudguard, fuel tank and seat hinge all need to happen side by side, to make sure there is enough room for everything.
Hmm... let's seeeee..... anything else left to do? bit of petrol, kick it and off you go!

Thursday, December 9, 2010

More AMAL wonderfulness.

Highly recommended reading right here folks.
This will answer pretty much any questions you might have regarding the Mk1 Concentric (A.K.A. the best carburetter in the world) as well as provide information that's otherwise impossible to come by - reliably - to do with jet stampings, changes by year, etc.
Detailed and very clear photos, step by step instructions, everything you need.
GO! read it now!

Wednesday, December 8, 2010

Cold over there...

Man, this winter is really kicking my ass...
I'll bounce back, just you wait.

Monday, December 6, 2010

More A50 literature.

There's something about period brochures that just makes me happy.