Category Archives: BMW

A Strip of the Old Bike 4

While I’m working on the old girl I’ll take the chance and make a couple of upgrades.

The first is the rear brake pull rod. The current rod is original to the frame and is over 50 years old. The adjuster nut is beginning to jump the thread so I’ll make up and fit a new rod while I have the chance, it’s been intended for a while so the materials are to hand, a clevis and a length of 6mm rod.

First step was to thread the end of the rod to take the clevis, with this in place the rod was cut to the same length as the old one and the free end threaded to match the old.

Next is the adjuster nut. The original is a brass wing nut so you don’t need tools to adjust it. The idea is good but proximity of the silencer makes it awkward so a new one made from a bit of brass hexagon rod is indicated. This can be adjusted using a deep socket and extension bar or an old-fashioned box spanner (tube spanner for those in the colonies).

Manufacture is simply just a case of drill and tap it 6mm, turn part of the length down to about 10mm diameter and cut to length. A bit of work with a file to shape the end to a saddle for on the lever roller and that’s it.

The other is the link in the gear-change train.

The original link here is a length of steel rod with a 90º bend at either end.

I’ve always found that this puts the lever a bit too high and have been meaning to change it for long enough. I’m doing it sophisticated like though, using a pair of rose joints and a threaded bar.

I’m being really posh though and having the rose joints left and right hand threaded so the final position of the pedal can be easily trimmed to suit, just means I need to get a left-handed 6mm die up from Tracy Tools.

The bike’s gear levers each have a 5mm clearance hole for the original rod while the rose joint mounting studs are 6mm thread. Tapping size for 6mm however is 5mm so rather than just open them out a bit I’ll run a 6mm tap through the levers, screw the rose joints into place and fit a lock nut as a “belt and braces” to secure them in place. I could have just done this using clevis joints on the rod ends but the rose joints are a neater answer.

I’m now nearly at the point where I can start the re-assembly, there’s just the rear swinging fork to repaint. Once that’s done I’ll refit it temporarily and take the opportunity to properly centre the rear mudguard.

At the moment it has been done by eye, the original position needed altering due to having a car tyre fitted at the rear end.

Normally on a BMW the wheel runs biased towards the right side of the swing fork. This allows space to remove the wheel so, while the wheel may be centred in the frame, the swing fork is not.

Using the wider car tyre meant that the wheel had to be shifted over a bit as the right side of the tyre was fouling on the swing fork so the mudguard was no longer centred on the wheel and had to be moved over as well.

While the guard was moved across a bit it was not quite enough as at full bump the left side of the tyre rubs a bit on the inside of the guard. It only happens on full bump though so I’ve been living with it but I’ll take the chance of fixing it while I have it, if I shift it by 10mm that should do it but any more and I’ll foul the other side.

A downside of using the fatter tyre is that to take the wheel out now means that I have to remove the final drive as well, but this is more than compensated for by the increased tyre life.

I’ve already checked the tyre against the rear mudguard and there is clearance, but not much so a future project will be to make up a wider guard.

UPDATE

I’ve just refitted the mudguard to measure up to find that the problem was not that I had not moved it far enough over the first time, the top of the guard was centred on the tyre.

The problem was that I had not moved the bottom front mount over as well, the front of the guard was still on the original mounting so the guard was twisted!.

All that was needed was to reposition the front mount and the job was done!.

A Strip of the Old Bike 3

Well that was the plan, but with the rear end stripped away there’s so much weight on the front wheel that it’s difficult to raise it off the ground when wheeling the bike on the dolly so manoeuvering it around is awkward.

Answer is to make up a “skate” for under the front wheel using some old castors, which has the added advantage of bringing the bike back to nearer level.

First try with the skate under the front wheel resulted in the wheel turning as the bike was moved forward and coming off the skate but a lashing round the front brake lever sorted this out, and I put a pair of eyes onto the skate and another lashing through these and the front wheel kept the skate in place.

Final piece of the strip was to take out the gearbox, this was strictly speaking not really needed but I’ll take the chance while I have it and clean off and lubricate the clutch splines.

Now I’ve the decks cleared it’s just a case of set to with a wire brush in the angle grinder and clear the sub-frame to bare metal.

As paint does not hold well if there’s any trace of oil on the bare metal it needs swabbed of with a non-oily solvent before it is coated, I’m using “Panel Wipe” which seems to be naptha based, wipes down well and dries quickly.

First coat is an etching primer, to “bite” onto the metal, followed by a couple of coats of a high build primer to level things off and this is allowed to dry thoroughly before the top coat is applied .

I decided to work on one side at a time so the nearside of the rear sub-frame was attacke with the wire brush and taken back to bare metal. Using a brush in the angle grinder is very effective for this but the downside is that the brush tends to shed bristles so a faceshield is a MUST when doing this, you also find that the shed bristles will snag into clothing and jag into you later on!.

Once it was cleaned down I then wiped it over with Panel Wipe and then applied the etch primer.

What I’m using is a rattle-can etch-primer filler from the local car-body shop, it does the job well but the downside is that you need to shake the can vigorously for two minutes after the ball starts to rattle, this is one of those occasions when time d-r-a-g-s on!!.

The job was then left overnight to dry out thoroughly, I’m not in a mad rush here after all.

Next day I went into the garage and was met with a strong smell of petrol. Initial thought was that I’d left a fuel tap turned on but investigation showed fuel wet along a tank seam and a s-l-o-w drip from it, bloody ethanol fuel finding a weak point on a seam!.

So I drained off the tank and reviewed the options.

These are:-

1 – Get a “new” tank.

2 – Use a tank sealant.

3 – Farm the job out.

Well, taking them in order.

Option 1. A replacement tank from Motorworks will cost around £300 and it will need modifying to fit on my bike.

The bike is a “convert”, an Earles fork frame fitted with a later and more powerful engine/gearbox unit. Why do this? Answer is that the Earles fork frame was built with sidecar use in view while the later one is not and a “convert gives the best of both worlds for sidecar use. However the tank moutings are not compatible so a new bottom will need to be put into the tank to match with the older frame. Option 1 goes out the window!

Option 2. The tank already has a sealant in, one that has failed. The existing sealant was put in back in 1986 when the tank was modified originally and it has succumbed to the attack of the ethanol added to modern ersatz petrol so this will need to be stripped out before any new sealant can be used.

On to the ‘net to find out options here and find various options most of which will not work because of the design of the tank itself.

On the net however I find reference to a firm only 20 miles away so I decide to investigate further and decide on Option 3.

They will bake the tank to clear it of fumes, cut it open, blast clean it inside and out, repair any “imperfections”, close it up again and buff out the welds. Then they will internally seal the tank and prime the outside.

As a bonus, the tank is an ex-police one with the radio box in the tank. They are going to remove that to open the tank for blasting but instead of replacing it they will patch where it was, giving me a bit more tank capacity and the possibility of using a standard tank cover and tank bag.

It’s going to cost around the same as getting another tank would, before paying out to have it altered

but it will in effect be a new tank, I’ll need to paint it, but that was on the schedule anyway.

A Strip of the Old Bike 2

With the body out of the way it’s easy to get to the sidecar’s mount points.

There are 4 of these, the two upper being clevis joints and the two lower are ball and socket clamps.

Once the top braces are removed the chassis will try to fold up towards the bike so first thing is to put the bike onto its centre stand for the first time in years.

I’m making all this sound easy, well there’s none of it particularly difficult but when you’re working on your own and have to manhandle the bike around it raises problems.

To make moving the bike around easier I’ve got one of those wheeled platform dollies that go under the centre stand so the bike can be moved around in any direction, I’ve just to get it under the stand, a pig of a job because the bike is on smaller diameter wheels than when it was a solo and so it’s not only a higher lift to get it onto the stand but the roll-on action only comes into effect once the rear wheel is around 2 inches clear of the ground, before that it’s a deadweight lift.

I’ve come up with a cunning plan to help with this.

I put a length of 2 x 4 timber on the ground behind the rear wheel with another length on top of it but stepped back so there were two 2 inch steps.

I then backed the bike back onto these and then I could lower the stand.

Unfortunately while there was enough height to lower the stand it wasn’t enough to slide the dolly under.

So it was a case of moving one of the 2 x 4’s to between the bike and sidecar, digging out the scissor jack from the sidecar boot and using that under the rear sidecar mount and at maximum lift I just managed to slide the dolly under the legs of the stand.

It’s now standing on the front wheel, the sidecar wheel and canted onto one leg of the stand but once the top brace fittings are removed it drops over onto both legs of the stand.

Both lower mounts have a drawbar to close the socket jaws onto the ball so it’s loosen this off, and then it’s twelve full turns to get the jaws wide enough to clear the balls before the chassis can be lifted away.

Well that’s assuming the jaws will open, one pair wouldn’t until given some “percussive maintenance” with a 2lb hammer!

Now, the aim of this job is to repaint the rear sub-frame so what’s in the way?.

First of these is the silencers, so off they come, they’re stainless steel, bought back in the late 1970’s and all they need is a clean and buff up, well worth the money they cost!.

Next off is the rear wheel.

When I took the rear wheel out I noticed that the tyre tread was down to just above the wear bars, so that means I’ll need a new rear tyre while I’m at it. This raises a neat point though.

The rear tyre is a 15 inch car type so it’s wear bars are set for car use, but the wear bars on a bike tyre are set lower, 1.6mm for a car but at only 1.0mm for a bike. I’ve no desire to try to argue the point with either the police or the insurance however so there’s a new tyre on the list now.

I’m going to go the whole hog here and remove the rear swinging fork as well, Think Big!.

To do this means splitting the shaft at the gearbox coupling, just undo the rubber boot and undo four twelve-point headed bolts and that’s done.

But first the rear mudguard has to come off , only hassle here is the electrical connections, I’ll look to improving these while I’m at it, while BMW themselves used a choccy block connector on the /2 models that this combo is based on, I’m going to change it to a multi-connector and tidy up the wiring.

Then you undo the suspension units, unscrew the pivot bolts and the whole thing lifts away.

All that’s left to do now is remove the seat and tank so they don’t get damaged and I’m ready to start stripping off what’s left of the old paint, a wire brush in the angle-grinder will make short work of that!

A Strip of the Old Bike 1

The R80/2 outfit has been on the road now for a goodly number of years now and the rear sub-frame is badly in need of repainting.

While in theory this can be done “as is”, access will be atrocious so to get round this the sidecar will have to come off.

Fortunately the standard fittings on a Steib are so designed that taking the outfit apart will not result in losing the alignment and I will be able to just bolt everything back together at the end so that’s one worry I don’t have.

Anyway, as I have the battery mounted on the sidecar chassis the first step is to remove that, it’s a car battery held in by base clamps so it’s remove the terminals, undo the clamps and lift it away, before going on to disconnect the electrics.

While I’m doing the bike I’ll take the chance to touch up the sidecar body as well and this means taking the body out of the chassis.

On an “S” model Steib the body hangs from four mounts in a loop chassis, the front two being pivots and the rear two sprung. Because the body is separately sprung in the chassis means that the chassis itself can be stiffly sprung, which improves the handling of the whole outfit and is why a Steib makes such a good sports outfit.

Since the body hangs in an open loop, before undoing the body mounts I’ve put a web strap under the body but over the chassis loop at front and rear to support it while I remove the mounts and once these are undone it’s just a case of lift the body clear. Sounds easy, BUT, because I’m working on my own here what is an easy lift for two is not for one!.

What I’m doing is to support both front and rear on jacks so I can wheel the bike and chassis forward from under it, but I’ve to be careful as there is a chassis cross member between the jacks so it means wheel forward for about 18 inches, reposition the front jack and than wheel forward again, all the time praying that the body does not topple off the jacks!.

What on paper is a half hour job winds up taking up most of the afternoon, Typical!

R12 Oil Leaks

Last time out on the BMW R12 I ran into problems.

What happened was that she was blowing oil out from in front of the magneto and the entire left side of the motor unit was dripping with oil. It got onto the HT lead on that side as well and so was giving an intermittent misfire on that side, she’d run happily along the straight and level but show her a hill and the misfire appeared!.

Of course when the job was thought out and planned there were other items called for as well as those on the “Wish List” of items marked up as “I’ll get those next time I’m ordering something” so I wound up with a bill of around £100!, fortunately a couple of “extra” items were “Not currently available, Please re-order” which cut the bill almost by half and began a new “Wish List”.

When I had a closer look I could see it was blowing from the outside of the seal carrier plate so a new cork gasket seemed called for.

Once the bits arrived it was down to work.

First thing was to get the sidecar off! Fortunately it’s mounted using Steib type DIN Standard fittings and the electrics are through a plug and socket connection so that was not a difficult or prolonged job, just a bit awkward when working on your own.

Then it was a case of clear the decks for action!. The tank had to come off to get easy access to the top of the engine unit, not an essential but it makes life SO much easier it’s worth the hassle.

But to remove the tank the seat has to come of first, and that bolt at the saddle nose is masked by the nose of the saddle and so is fiddly to undo and get out.

Now comes the not so obvious!. To replace the gasket I have to remove the magneto, which means it will have to be re-timed and on an R12 there are two ways to do this.

One way is to remove a cylinder head and set the timing 12mm BTDC on No. 1 cylinder. This means sacrificing an expensive head gasket. Not only that but on an R12 the head nuts are in between the cylinder finning, are awkward to reach and only accessible with an open-end spanner.

However there is the option of timing off the flywheel.

Some, but not all, machines have their flywheels marked for TDC and full advance. These marks are on the rear face of the flywheel and to access them means removing the gearbox, which means splitting the drive shaft.

My flywheel is so marked and I decided to go this route.

So, let’s get the gearbox off, Easy there’s only the two bolts through the clutch bell housing at 3 and 9-o-clock! If Only!

First is to get the shaft off, slack off the backlash to access the spring clip behind the drive flange, “persuade” it out of its groove (easier said than done!) then telescope and remove the shaft after removing the two nuts at the bevel box.

Next is to undo the two bell housing bolts, plus the one hidden under the engine at the 6-o-clock position!, I’ve seen a pair of crankcases that had been broken through forgetting this one!.

The gearbox still won’t come out yet because the long rear engine bolt goes through its housing!, so that has to come out and we’re not done yet! There are a pair of studs facing downwards in the bell housing itself at just below the 3 and 9-o-clock positions that allow the housing to clamp onto the gearbox and that need to be loosened as well before the gearbox will come out, promptly followed by an expletive as I find I’d forgotten that I’d put an earth lead onto one of the casing stud nuts!.

That’s the decks cleared for action, and it’s taken longer to do than the repair does.

At the top front of the engine is a small cover held by two bolts, remove this and you have access to the magneto sprocket.

Book method now is to split the timing chain, undo the magneto securing strap and slide the magneto out, however it is also possible to tilt the magneto and gain just enough play in the chain to slip it over the sprocket and so remove the magneto without having to remove either the split link, or the sprocket securing nut and washer, with the attendant risk of dropping parts into the engine!.

Once the magneto was off the problem became obvious, the cork sealing washer was compressed to the point of having no “give” and it was hard enough to strike a match on! No wonder it wasn’t sealing!.

Not only that, but there is a coil spring goes between the magneto and the seal housing to compress this cork gasket against the engine casing and this was “tired” to say the least! Fortunately I’d put a replacement for this spring on the list!

So now all that had to be done was to remove the magneto sprocket, replace the coil spring, refit the sprocket (leaving it loose), then grease up the new cork seal and refit the magneto.

Now came the fiddle! Retiming the ignition!

You set the timing on No.1 cylinder, the one on the right hand side so it’s turn the engine over till No.1 is on compression stroke and the timing advance marks are aligned, that’s step 1.

Step 2 is to set the magneto onto No.1 as well, this is with the rubbing heel of the points pointing towards the left and adjust the magneto so that with the ignition lever on full advance the points are JUST breaking, simplest way for this is a slip of cigarette paper (Rizla Blue are thinnest and best for the job) nipped between the points and then, when the points grip on it is JUST eased, to lightly nip up the magneto sprockets securing nut.

Now turn the engine over again a few times and then check that the points are still JUST breaking as the timing marks align and if they are then you can fully tighten the sprocket securing nut and replace the sprocket cover.

Now it’s just reverse the disassembly, offer up the gearbox with the usual hassle to get the clutch splines to match, and bolt the gearbox into place. Refit the shaft, slide the drive flange pins into the Hardy disc.

Now you just have to refit the spring clip into its groove, set the freeplay on the shaft to between a half and one millimeter and then all that’s left is to refit the tank and seat and we’re ready to roll.

After a test ride solo the sidecar has to go back on and here’s the beauty of the Steib, DIN Standard fittings, it is not necessary to re-align the sidecar the original alignments are still good, they have not been disturbed by the removal/replacement.

Chair Problems

A couple of posts ago I said I had a problem with the R80/2 sidecar outfit and I decided to get this sorted out before I started on the R12.

The problem I had was with the sidecar’s mudguard (fender).

On a Steib this is a big, Art Deco affair. Originally it would have been a pair of steel pressings spot-welded together but this was replaced with a fibre-glass (GRP if you prefer the term) replica about 40 years ago.

At the rear of the guard a chassis tube goes through it from side to side and the guard is held in place between a pair of conical mounts (there is a reinforcing cross tube goes here, between the two sides of the guard).

What has happened was that over the years the fibre-glass guard had gradually worn at the conical mounts until the inboard one pulled through. The guard then could move/bounce on the cross tube and by the time I got back home, I was some 150 miles from home when it went, the hole in the guard was not only oversize but oval. On further examination I found that the outboard mount was also “somewhat under par!.

Normally a repair on a fibre item is a simple matter, just clag on a bit more mat and resin! but here I needed to reform the seats for the conical mounts so I needed a former.

As I only needed to make up two mounts I just made up a temporary former using MDF board.

The maximum diameter of the conical mount was 50mm so I cut a round of inch thick MDF that size. The diameter of the cross tube is 32mm but as there needs to be a clearance on that I worked with 35mm as the minimum and I carved it down to a cone of those dimensions and 15mm high so I had a 35mm cylinder an inch high with a 15mm high conical base.

Next step was to make up a female piece to match this, as there was only space on the inside of the guard to take a 100mm square block this determined the outer dimension of the female mould.

When you are working with fibre-glass you normally have only a short “time window” to work in before the resin starts to gel and owing to the nature of my intended repair this was a problem.

However there is an alternative resin available, “Epoxy Resin” rather than the more usual “Polyester Resin” and this has a longer pot life, of around 6 hours plus rather than only 15 minutes and so I opted to use this.

Rather than just try to patch the guard I used the mould to make up a light support moulding for the main repair.

I took a 150mm square of MDF and drilled an 8mm hole in the centre, there was already a similar hole in the round male block so I fixed them together with a length of 8mm studding (allthread) and gave the resulting plug a good coating of mould parting compound, and I similarly dosed the female block.

Then I laid up the mould, using a layer of fine glass cloth and a single layer of chopped strand mat. I then put the female part over the centre piece and used the studding to force it against the lower part and left it overnight to cure.

When I extracted the “casting” from the mould I had what was to become the outer surface of the repair just needing trimming to size.

I then re-assembled the casting onto the mould plug, but this time sandwiched a sheet of polythene between them, the resin will not stick to this and it meant it would be easier to remove the plug.

A single layer of the chopped mat was now laid up onto the back of the casting and another onto the guard itself, being generous with the resin, the moulding put onto the prepared guard and the whole turned over to let me work on the inside of the guard.

The casting was adjusted for position to correct for the wear to the guard and the wear gap made good with mat and resin and then another two layers of mat and resin laid up on the inside of the guard.

I’d bored some 10mm holes through the guard so that the resin would bond through them to combine both sides of the repair together.

Once I had the inside laid up I put a sheet of polythene over it, put the female part of the mould over the plug and again squeezed the wet resin/glass layers together and again left it overnight.

Next day I removed the mould, a fairly easy job thanks to the polythene.

I then had to set to and repeat the whole process for the other side of the guard but once that was done all that was left to do was clean up the surface, fill the blebs with bondo, rub it down and get out the rattle cans to repaint.

It’s not a perfect job but you have to look to see it and as a new guard is around 250 quid plus carriage from Germany I’m willing to live with it for use on the road hack.

If I’d been willing to cut back with a sander on the outside of the guard after the repair it could probably have made to look as original but this is the main mount point for the guard and I’d rather a bit of strength over cosmetic perfection.

Parts Hunt

As I was needing parts to fix the R12 and there were a few other items on the “next time I order” list I sat down and drew up a shopping list.

Then it was a case of going “on ‘net” to source them. There are a number of places where you can get R12 parts on the continent so I checked them out to find that none of them had the full list!

I wound up ordering from Switzerland as they had almost the full list, all they did not have was a small gasket, one I can make myself if necessary. Parts were ordered one evening, two days later I received an e-mail saying they had been sent and the next day TNT were knocking on the door to deliver them!

Only snag was that the replacement seal carrier I wanted wasn’t available, “Please re-order later”!

So I turned to the only other place that listed that part, sent in an order and got an e-mail back that they did not have it in stock either!! Looks like there has been a run of R12s blowing their oil seals!.

Fortunately it is not a complex part so if the worst comes to the worst I’ll have to turn to and make one, only snag is it will mean having to trepan a groove in the carrier and that needs a fancy cutting tool, one I don’t have of course.

Blown Seal

After the run out to the Corbridge Show on the R12 the next outing was to the VMCC’s Scarborough Touring Week.

As this meant a week away under canvas I opted to take the old girl down there on a trailer behind the car. Reason for this was simply that I would have been unable to carry all the gear for a weeks camping for myself and the two dogs on the outfit.

On this event there is a road run each day and there is the social side each evening so it makes for an enjoyable week away.

Day One was the Friday with the run down the A19 towards York and then across to Scarborough. I chose this longer route because there are severe hill climbs with tight bends on both of the shorter routes, one being up Sutton Bank and that’s bad enough without a drag behind you!.

Anyway I got to the campsite in good time, offloaded the outfit and set up camp in time for the first evenings socialising.

The Saturday was a short run out, only some 60 miles around the area and everything seemed ok but when out on the Sunday problems arose.

The R12 has a separate Magneto/dynamo unit sitting on top of the engine. This necessitates a seal between the two and this blew. There is a carrier plate with a felt seal against the magneto end plate with a cork ring gasket sealing the plate to the engine housing and this is what blew, covering the left side of the motor in oil.

The oil got onto the plug lead and gave the spark on that side a pathway to track to ground and short out the plug.

Just to be awkward it would only track when the motor was under load, as when on a steepish climb, but when light loaded she ran OK! Typical!!.

I limped back to the main road on about one and a half cylinders and once on the main road it was a level run back to the camp-site so, of course she ran sweet as you like under the light load.

Monday was a run out to the aircraft museum at Elvington, near York, and rather than risk things I went over there with the two dogs in the car and had a good look round but I’d have preferred to be on the bike.

Tuesday was the “Extreme Hill Run”. I’ve done this run before using my R80/2 convert rig and it had tried the brakes on that lady so I had opted not to go on that run when I booked for the event.

This gave me a day “on site” when I could have a go at fixing the bike.

I tried various options at the “roadside get you home bodge” level but without success, it seemed the inner felt seal had gone and I was going to have to take the magneto unit off the bike to fix things.

This would have meant losing the magneto timing and this was not a job I wanted to undertake on a camp site, it’s not all that difficult but it is rather involved with an R12 outfit, meaning taking the sidecar off for access and then removing the gearbox to access the timing marks.

Wednesday I opted to stay on site again as the weather was rather inclement, i.e. it was p—ing down and while I could have gone in the car, I don’t see the pleasure in driving in rain any more than in riding in it!

Thursday dawned a nice day, but owing to other commitments at home I needed to back by Friday so it was a case of see the Thursday run out off, then pack up and drive home.

So, to fix the R12 I’ll need to get new seals and some other bits for her. These will have to be ordered up, probably from Germany, so it looks as if she’ll be off the road for the rest of the month, I’ve the R80/2 combo off the road with a repair to the sidecar so I’ve only a solo on the road at the moment.

Means I’m restricted in what I can do because of the two dogs, Looks like I’m just having to go to local events till I get an outfit back on the road.

First Run Out

Went out for a decent run on the R12 combo on Sunday, around 70 miles all told.

The sidecar chassis I’m using on her is the same one I took off her some 5 years ago when I started working on the Panther and needed the space in the garage.

When I put it back on I just bolted everything up “as was”, assuming the fittings had not been moved so, although Steib fittings are reputed to be good for this trick, I was a bit apprehensive first time out.

I’d taken her out first for a couple of miles to make sure there was nothing drastically wrong but this was to be the first real test of things.

So it was a case of load up, dogs in the sidecar, fire the bike up and away we go!.

All outfits tend to flutter their bars as you pull away, once you are used to driving an outfit you only notice this if it is excessive.

Use of a steering damper limits this but where your damper is the old-fashioned friction type it can stiffen up the steering generally.

I had my damper set at 3 clicks from off (one click gives JUST enough rub to keep the damper plates clear of rust when running as a solo) and did not notice any flutter worth commenting on so that was a good sign to start with.

Next was how stable the steering was. The R12 has a hand operated gear-change so you need to remove your right hand from the bars to change gear. If there’s any instability in the steering this is where it will show up and it didn’t, no wobble detected.

Now an outfit is a peculiar vehicle, it is a twin-track machine but is driven and braked on one track only. This means that, when the outfit is properly set up, on acceleration the bike tends to pull towards the sidecar and on braking the sidecar tends to pull towards the bike so that when on the open road much of your steering is done with your throttle. Much of the “Black Art” of sidecar riding is in getting to know how to use this.

If the set-up is incorrect then the outfit will tend to always pull to one side or the other. So, how was the R12?.

Answer is “Just about right!”. She steered nicely on the throttle and also ran straight when on a steady gas, it only needing one finger on the bars to hold her straight, always a good rule of thumb!.

After some 20 miles I took stock a bit, the R12 is lower built than the Panther, this results in the bars being lower than I’m used to with the Pussy and a feeling that I’d prefer them to come about a inch and a half further back and the same higher. I don’t remember this feeling when I was riding her before so it’s just going to be use.

The R12 has footboards whereas the Pussy has footrests, in theory there is greater choice of position on the R12, but it’s a boxer twin, you’ve a cylinder complete with carburetter in front of your foot so in fact there’s very little difference.

Another difference is that the R12 has telescopic forks in comparison to the Webb girder fork on the Puss.

Telescopic forks are at a disadvantage for sidecar work compared with either a good girder fork or a link fork, they have an inherent flexibility which does not affect handling as a solo machine but does affect a sidecar outfit, however those on the R12 have only a limited range of movement available, and given the limited performamce of the old lady this is acceptable in this case.

How did she perform?. Well remember the old girl is 80 years old and what was considered good back then is slow now. I have a Sigma electronic speedo fitted to her which has been set up on a measured half-mile nearby. On a major road along the level I was comfortably holding an indicated 41 to 44 mph. On hills this was dropping back to around 38 to 39 mph.

I was seldom over about half-throttle so there was power in hand, and one thing you rapidly learn with an outfit is to always have that “bit in reserve”.

Performance is comparable to that of the Pussy on chair, a difference being however that while the R12 is pulling sidecar gearing the Pussy was left to pull her normal solo gearing.

This means that under ideal conditions the Pussy will be faster on sidecar, she will tend to “bog down” more, requiring more frequent use of the gearbox and dependance on the intermediate ratios.

Conclusions are that I’ll soon get used to the R12 outfit again, that what is said about Steib fittings not loosing their alignment when the sidecar is taken off the bike is true, and that as I discovered when manhandling the two different chassis around off the bikes that the Steib chassis is considerably lighter then the Watsonian!.

Reason for this will be that the Steib is welded construction while the Watsonian is a hearth brazed fabrication with heavy forged lugs and straight tubes giving the Steib the same advantage the Featherbed Norton frame had over its rivals.

Meet The R12

Looking back on the last few posts I can see that I’ve been talking about the BMW R12 but there have been no pictures to show what that is, so this is her ladyship :-

This is showing the sidecar side view :-

Front Quarter view is :-

And the view most likely to be seen by other traffic (as they come up to overtake 🙂 )

And as they pass:-