The SR500 sidecar - some setbacks on the way to becoming a usable daily

Admittedly I haven't cranked up quite as many miles as I would have hoped, but definitely have broken the engine enough times during the Summer months, so I guess this kind of evens out. But even then a few things have come apparent: 

The clutch lever I had on there, even though labeled for an SR500, definitely wasn't and I have to find a spare brake lever, but it's this weird ball and socket setup and I have to find out from which bike the master cylinder originally was. 

The other thing that drove me (mildly) nuts was the fact that the exhaust, despite my best efforts, was rattling itself to death and leaked at the joint between down pipe and muffler at the same time. Also, I am a strong believer in touching up the welds, for optimised flow. 

Also a proper joint and not the wobbly mess I had so far did wonders just to how rigid the whole setup felt. As can be seen in the first picture, the original tube had actually been eroded away from the muffler and the down pipe oscillating at different frequencies.

Added a slip joint on the muffler, so the exhaust gasses would have to do a 180 to get out, which makes it a lot more likely to seal up without a gasket than if you put it in direction of the flow.

... and then shortened the header pipe by roughly the same amount, so one would fit into the other.

What followed were a few days of happy thumper-ing along, when my sporty ambitions came back to me (maybe somewhat helped, by rather abysmal starting at even slightly cold weather) and I decided to throw that second hand TM36 back on. Instantly a few more kph of top-speed were found, but something didn't feel quite right. 

At some point, I had a look at the mix screw and found that the actual tip had snapped of inside the carb body. Throw in a few desperate attempts to get that tip out and it was decided to do, what I should have done from the get go.

Get out my wallet and buy a new TM36 and simply enjoy it. 

Not without swapping those JIS-screws out for some stainless allen-heads. (Whilst rejetting to the same jets I used on the previous TM36.)

You may not believe this, but it took two kicks and the SR idled like... well like a bike with a carb that no one has fiddled around with.

So I fitted my elephant ears (even without snow they are super handy to get the wet and cold away from your fingers), put some fuel in my freshly painted tank and...

F*ck.

Removed the paint with fire (don't - I am a professional) and then repaint it with 2K-paint.

As I only had spray-can primer, I pre-heated the inside of the tank until was (very) warm to the touch, which made this whole affair doable, even though it was only about five or six degrees above freezing outside.

And that's it. Put on some wax and then find out if the new TM36 responds well to my jetting efforts or whether my timing might be off - guess we'll find out. (Oh and for those wondering, yes I am currently mostly working on the Lada, but not quite there to show some updates, as in: lot's of work, yet not quite as much to show for it...)

Little addendum: The carb setup is pretty close, starts nicely and can finally take full speed/full throttle for a while, which makes me quite happy.

Comrade Car - clutch and brakes (Part 4)

If there's one thing that Comrade Car has already taught me about, then it is the fact that even economy spare parts are mostly made to vastly different standards than what came factory in the 1980ies. At least as far as all sorts of plastic and rubber are concerned, when it comes to metal - totally different story.

Take this beautiful clutch slave cylinder and it's hydraulic line...

 ... or the expansion vessel for the coolant. I swear, I only tapped it with my finger and it shattered like glass.

So out with the old clutch-slave, assemble the new one and chuck it in. I really have to give the Lada engineers a thumbs up here, because you can totally do this on the side of the road with not much more to remove than the spare tire.

And on almost the same matter - right when I sat in Comrade Car for the very first time, the brake pedal fell straight to the floor. So a complete brake overhaul was due.

At which point something absolutely amazing happened:

That's right, no heat, no violence, just take the drum off, swap the brake cylinder and re-assemble. Thanks to the unknown previous mechanic, who went through all the trouble and slathered all mating surfaces in anti-seize.

So next were the fronts. With this being a Lada Niva, they actually are both very weird and rather ineffictive, as the car basically sports two front brake circuits, one of which is also connected to the rear. Also the actual brake design is sort of free-floating, but not really. 

Everything is held in place with these D-shaped rings and a pin through it.

Guess what took "a bit of persuasion" to come out. Defintely the bit of kit you buy new or at least have in stock, whenever you do the brakes on one of these.

Respectable Lada-owners told me that usually the pistons never fail, but the seals inside the piston are a bit hit and miss. Well, I got lucky and had one piston, which was still good enough to be used as a template. That being said, the sketch in the background is just that - if you want to machine your own brake pistons, it will let you know that each one is 51mm long and has got an outer diameter of 30mm.

As you can see, I deliberately omitted some features (it's a sketch), so if you really want to make your own, take one of the pistons out and take the features off that one.

I decided to make them from stainless, as I don't really want to do this again any time soon. So after standing at the lathe for quite some considerable time, I had this in my hand.

The really big job is to clean the o-ring groove on the inside of the calipers as due to aluminium corrosion they will shrink and thus cause the piston to seize in the bore. (Which is also the reason, why normally the pistons aren't really the problem here.)

The other thing to note: the actual calipers are held in place with a pin, about which most people will tell you to drill it out. I found a much better way is to punch it in as it will get stuck on all the rust at the bottom, allowing you to quite easily free the caliper from the holder. Now the big trick here is, to fill the hole with some penetrating oil (so far not very surprising) and apply quite some heat. (Best done before resealing the caliper.) And then push it back a few times. After a while it will just happily fall out, the bore can be cleaned and everything assembled with a bit of grease, keeping that pin and spring assembly happy and in place. Also the pin has a locating pin for the spring on it, i.e. it's got a correct orientation. 

Generally "lube everything" appears to be a pretty good strategy on this car. So all the pins and springs have been installed with plenty of copper-paste and the mating/sliding surfaces have been cleaned with a wire wheel.

After being warned (again by some more experienced Lada drivers) that bleeding the brakes is more than "just a bit" of a chore, I built my own little pressure bleeder, by using a cap from an old Lada reservoir and drilling the top to feed through a valve stem. This way one can apply some constant pressure with the compressor and very comfortably bleed the brakes without needing assistance.

From here onwards it was a case of about one litre of brake fluid and about 30 minutes of bleeding on all four corners.

And in essence that's the brakes done on the old girl.

The SR500 sidecar - pinning down the rockershafts (Mk.2)

You've only solved a problem successfully, when you actually have tried all available ways on how to not solve a problem quite as successfully. This time the grub-screw modification as illustrated on quite a few SR500/XT500 forums. Whilst the solution is technically sound, it will only prevent the rockers shafts from lifting in their bores, but not from spinning, which is the original reason, why the bores wear out.

So let's turn that engine to TDC, remove the oilfeed to the rocker shafts and measure just how far in from the mating surface I drilled those holes last time. (8mm on both) and get those shafts.

Transfer those 8mm onto the shafts and with a new carbide endmill, make a flat on the rocker shaft.

Which brings us to the star of the show: M6x10 grub screw DIN916 (flat tip/no tip) as shown in the top right, which is in contrast to its tipped brethren on the left. Even though in theory the tipped version will be less likely to work itself loose it has no means to prevent the shaft from rotating. Given the not unrealistic concern regarding the grub screw coming loose: bolt adhesive has been invented already.

For the rear screws (yes, two stacked on top of each other) a cheap allen key from a well known furniture house had to be shortened on the long leg.

From a technical point of view, now this 2J4 head has reached the same level of rocker shaft retention as the later 48T mode. From here onwards, wear should only occur between rocker and shaft and judging from what I've heard these thanks to a good material combination and plenty of lubrication should last quite a while, before a replacement is due.

The SR500 sidecar - pinning down the rocker shafts

 Pinning down the rocker shafts - what's it all about? In short the rocker shafts in a SR500 cylinder head should be an interference fit, making sure that the rockerpads are nicely parallel to the camshaft axis. When they start to spin, initially nothing much happens until the rocker shafts wear out the bore allowing the rockers to move up and down in the bore at which point the wear rate accelerates and rather soon than later, you end up with egg-shaped holes and rocker pads which do not wear evenly in the center but on one side. In the process of which this will not only lead to premature wear on the rockers, but also on the camshaft. Most notable because it sounds like some angry troll is swinging a really big hammer in the top-end of the engine. The fix is pretty simple: four M6x10 grub-screws, a few minutes on a drill press and some loctite.

Leading up to this point, a few more things had to be tackled. First of all, was to polish the valve covers. Yep, you read that right, a pure job of vanity. Remove the flaking, yellowed clear lacquer and then go to town with ascending finer grades of emery and then buff living daylight out of them. Technical value of this mod: -1, i.e. completely pointless and I don't like freshly polished stuff. But scratched, weathered aluminium? Hell yeah, one really, really dirty secret of mine. 

Way more useful and completely unseen: a knurled nut as a petrol tank hold down. So at this point I can strip the whole bike off its seat and tank without a single tool. If you're messing about with one of these as much as I do, it's a real timesaver.

For example, when you have to take off the rockerbox.

Which can be done, without taken the engine out all the way, tilting it is actually sufficient.

Even though these are brand-new rockers, it's obvious, that the wear patch is nicely centred and very even on both. (Also a reliable indicator for good lubrication at the first startup.) The four bosses that are visible in this early 2J4 rockerbox are actually the spots where the later 48T-model will have bolts to lock the rocker-shafts in position and thus prevent them from spinning. In theory this will lead to more wear on the shafts, but with none (or next to none) on the heads this is a way better solution. Positioning might be critical, but the more I think about it, the more I am pretty sure, one could pull this one off on a 2J4 cover as well...

The actual modification can be carried out with drill-press and probably, if you're confident even with a handheld drill. I did it on the mill, because that's what I have. 

The upper "ears" of the head-mount obviously have to drilled out to 6mm afterwards or tapping would require a very long M6 tap.

The finished article. Loctite and lock-nuts is a bit of an overkill, but I think considering the extra-weight of the sidecar, those two M6 nuts should be bearable.

As a gentleman in general is not meant to motor after dark, it took me a while to find out that: the illumination in my tach had failed, I really want LED bulbs in both speed and tach (to save a few extra Watts for charging the battery) and the sidecar position light is super bright and blinding me - again fixed by installing a LED bulb. 

It says a lot, if you can notice the blinding of the position light in bright daylight...

And lastly - it's not a bodge job, if it works. Now all three contacts are soldered onto the LED cob, because the socket in this (admittedly) cheap Guzzi V7 sport tail-light is single-handedly the worst I have ever had on any bike. 

What next? Guess a few lovely Autumn ride outs won't do harm...