Idiot v. Motorbikes, Rounds 3, 4, and 5

[melville]

OK, first odd update. I'd started on this before I went out of town for three weeks and saw the stuff on the bench when I walked into the shop. I'd half forgotten about it!

When I got Edgar, these extra taillights were included:



As they were a vintage mod, I felt the need to reinstall them. Also because I'd installed the tail box, I felt the OG taillight might be a bit obscured. But because I'd shortened the turnsignal stalks for bag clearance, they didn't fit as they had been installed previously. I also wanted to improve the install with DIN wire colors, proper terminals, and an actual wiring harness rather than the loose black wires and Posi-whatevers and the wire nut the PO had used. There were challenges on the way. It seems that no one will supply 'one bike at a time' quantities of DIN wire. I even got in touch with a friend who does concours restorations of old Benzes and he said he saves wiring harnesses from parts cars and harvests wires. So for the tail/parking light (grey/black) I raided a harness I'd pulled from a 1964 VW Bus 20 years ago. The brown and green are new wires, but I'd have used green/red for the brake light if I had it in that VW harness.

I ended up using some AL strips to mount the lights below the license plate and rewired the lights with DIN colors, including a ground wire soldered to the light socket. Here's the result:



I had to go to eBay to find proper German style wire loom:



And secured it to the wire bundle:



A little aside here. As an old bicycle guy, I'd been using a 4th hand tool for tightening wire ties since forever, like so:



I picked this up as part of a large lot of other tools at a yard sale probably 10 years ago and never bothered to analyze it:



It pulls the damn things tight and cuts the stub off FLUSH all in one motion. Dammit! Now I have to go through all my shit and redo the wire ties! Back to the project. Lights mounted and loom housings cut to length:



I had to drill a new hole in the taillight housing as the wire bundle was too much to fit through the existing hole. Looms joined, shrink-tubed, and pushed through the new hole with a grommet:



Inside the housing:



All connected with piggybacks:



And the result:

[kmisterk]

new tail lights look slick. Also, TIL there's a tool to assist in tightening a zip tie that isn't just a pair of needle-nose pliers.

[melville]

Elsa begins! Today was sump-dropping day. The oil drained out good and black, with no obvious contaminants. I was surprised to find a solid filter and it was some cajoling to get it out without pulling the fairing:



I still have to get the o-ring out of the back of the canister. My bicycle spoke hook reaches in just fine, but it's adhering strongly on one spot.

The sump had sludge but no large or small bits o' metal:



The pickup and extension were in good shape, and all fasteners had been installed with loctite. The similar parts I pulled from Ernst had been hanging loosely.



I pulled the plugs and shot some oil down the holes and then, after pulling the front cover, turned it over from the alternator bolt and it moved quite freely. I'm encouraged. There may be a wee sticky spot where it sat for 37 years but it's something I can barely feel.

As money materializes I'll be buttoning the sump back up and filling it, rebuilding the carbs, and borrowing a battery to see if I can make it roar. From there, I'll be powdercoating the wheels and redoing the bearings and with some fresh tires and brake work, may take it out for some test rides.

The main plan is to detail the chassis and motor bits, to probably include a powdercoated frame and put it back together with the period sporty mods it has and any others I can find. I'm quietly looking for the SJ BMW frame brace that runs from the top trans bolts to the frame, for one, as I think the bike has the full Sport Pak kit otherwise. Presently it has the upper triple, fork brace, SJ BMW shocks, and a braced swingarm.

[melville]

The sump cleaned up just fine. No grit in the sludge. I thought I had pickup gaskets on hand, but I didn't, elsewise it would be back together already. No worries, the parts are ordered and should be here next week. In those parts will be rebuild bits for the carburetors, which I disassembled today:



No surprises except for a nice fuel smell even after 37 years parked. Possibly even leaded fuel smell. It sure didn't smell like anything we get from the pump today. You might be wondering where the big pieces of the left carb went. They're in my cleaner:



I'll pull them tomorrow and put the right carb pieces in there. Notes are important--I've saved this info for a baseline:



Conveniently the throttle plates had markings on them so I don't have to analyze how they fit in the carburetor. I've had to make my own marks on the 32mm carbs I've dealt with.

It was hard to read the numbers on the pilot jet but it looks like the right item. Nearly all the settings match up with the info in the Haynes manual.

[melville]

Little updates today. Parts came in and I've remounted the extended oil pickup, the sump, and installed a new filter. Three quarts of break-in oil are now in the sump, hoping to revive the rings enough to see what else it needs.

Next up are new diode board mounts and finishing the carb rebuilds.

I did find out that Elsa also has a lightened flywheel. Maybe not as lightened as Edgar's, but there's definitely been metal removed. So part of the job will be to find TDC and make a mark as it's quite possible the OG flywheel marks have been milled away.

[melville]

Little bits today. I started by replacing the diode board mounts. Two had separated and one was missing hardware. I cleaned up the starter cavity and the starter itself and reinstalled.

I did find that the flywheel marks were all gone from the lightening except for F. So I worked the crank around with a chopstick in the plug hole to find TDC and made a mark on the flywheel. I'm glad I now own a dialback timing light.

Once I had TDC it was natural to check the valve adjustment. Both intakes were at a 'loose zero' which may or may not have been intentional. It's something I useta do with ACVW that had aftermarket CroMoly pushrods. One exhaust was at .007 and the other was at .018. Intakes now at .004 and exhausts at .008.

The right valve cover was well stuck to its gasket and took some mallet blows to come off. The left one, only the center nut was on, and not very tight. When I got it off, I was dismayed to find the small nuts and ONE of the washers INSIDE the thing. I think the other washer was lost, and didn't find its way down the PR tube as the clearance around the PR is pretty tight.

Things looked good inside:





I'm happy with that, considering how crusty things were on the outside.

[Rob Frankham]

Do you know the 'accurate' way of determining TDC?..

Take a rod, your chopstick will do as well as anything else (but it's likely to make your chow mein taste funny). Make a mark on it about equal to half stroke of the motor. Insert the rod through the plug hole till the mark is in line with a definite point on the head then move the crank clockwise till it contacts the rod. Make a temporary mark on the flywheel adjacent to the timing mark.

Next rotate the crank anti clockwise until it just contacts the rod again on the opposite stroke (i.e. downstroke). and, again mark the flywheel. Needless to say, the accuracy of the result will depend on how accurate your marks and setting are. next go to the flywheel and measure the distance round the circumference between your two marks, then make a mark exactly halfway between them. This mark is TDC.

Why go to this trouble...

At TDC, the piston actually moves around 0.005 of a mm for each degree of crank rotation and, while this increases rapidly as the crank moves away from TDC, It's not until you get to around 10 degrees that the movement per degree gets up to 0.1mm... to put it another way, unless you're using a dial gauge (or a very accurate chopstick ) it's very difficult to get TDC with better than 5 or 6 degrees accuracy measuring the position of the piston at TDC itself.

On the other hand, at half stroke, the piston moves around 0.6 mm per degree which means, provided your measurement is fairly accurate, you can expect to get each within a half a degree so given three measurements instead of one, you could expect to get an accuracy of better than 1 degree... well within BMWs spec of three degrees.

I would still recommend that you do the exercise 4 or 5 times to ensure that you are getting a consistent result.

If I am teaching grandma to suck eggs, I trust you'll forgive me but TDC is one of the most important parameters for engine tuning...

Rob

[ME 109]

Do you know the 'accurate' way of determining TDC?..

I can get to about .001mm tdc with my dipstick.
It should have been mentioned in the manual.
For anyone who wants to get within .001mm of tdc.
I usually give my tank roundals a polish when working to those tolerances.

[melville]

Do you know the 'accurate' way of determining TDC?..

I can get to about .001mm tdc with my dipstick.
It should have been mentioned in the manual.
For anyone who wants to get within .001mm of tdc.
I usually give my tank roundals a polish when working to those tolerances.

If I had the trans off I could probably get very precise about finding TDC, but through the timing hole my chopstick method will be just fine. I actually had the chopstick somewhat sideways in the hole, so motion at the top of the chopstick was about 6X piston motion.

[melville]

The next step for Elsa was to spin the motor over and check for oil to the rockers. I had a guy say he might have a key in his collection, so I shipped the ignition lock to him to see about that. In the meantime, I went to the hardware store for a rocker switch for testing purposes:



I hooked up a battery with a good hot charge on it and was rewarded:



Then I tried hitting the button. Nothing. I cleaned up the contacts on the starter relay and bench tested it (seemed to do what was required), reinstalled and hit the button again. Nothing. Next up was jumping the contacts on the starter. Nothing.

I pulled the starter and bench tested the solenoid. Nothing. I'm just a couple years in this area and I'm still building my network of shops so I looked for auto electric shops and found one that seemed suitable. Last Monday I ran the starter to that shop. When I walked in, I was invited back into the work area. "So this is from a BMW, right?" He bench tested it, too, and pronounced the solenoid was needing service. Here's where he won my business: "I can sell you a new solenoid, but they're all from China. I have better luck rebuilding the original German ones."

He called back a couple days later and I got the starter back for a very reasonable charge. He replaced the solenoid with a German one from his stash because the original had failed in a way that defied repair:



Again in the bike, with a hot charge on the battery, and it was time to test. No love from the starter button, and I'm thinking there's some sort of interlock from the brake fluid level indicators, as they seem to be wired in to the neutral/clutch switch circuit through a diode. I can sort that out later. Presently there's no brake fluid on the bike. No master cylinder for the front brake, in fact.

So I got a big screwdriver and jumped the terminals on the starter and was rewarded with copious oil flow to all of them. Much more copious than I expected:



Cat litter was applied immediately. Seriously, it's a new floor and it's like an oil magnet. Stuff that doesn't leak elsewhere gets a drip as soon as it enters the shop.

Next up is finishing the carb rebuild and sorting the ignition. Once that's done Imma try to hear the thing roar. A little carb teaser: