Uncle Ben's BMW - Wheels
Today I started in on the wheels. They're pretty ugly.
I need to determine hub offset. The front was easy as the hub is symmetrical and it's centered on the rim so I didn't need to measure. The rear is also apparently centered, but the hub is asymmetrical, so I decided to measure where it sits. I just laid a straight edge across the hub flange and measured the distance to the rim. Looks like about 3.5/64 or 1.4mm.
The nipples were pretty badly corroded, so I just used the Sawzall to liberate the hubs.
Ever growing pile of cleaned up parts.
I discovered the rims are nice aluminum ones. They look like they'll clean up nicely, so I might just polish them instead of painting. I also found the u-joint was a bit notchy - but I've decided to throw it back in as there is no easy way to replace it, BMW wants you to just get a buy a new drive shaft.
If you recall, when I drained the oil out of the final drive I found a bits on the magnetic drain and a chunk of metal that was a wee bit concerning:
After reading up on airhead final drives, I realized I could remove the inner cover without disturbing the gear setup. (That anti-seize lube crap is a bitch to clean out of the splines!)
Well I found the rest of it and I was able to put Humpty Dumpty back together again - sorta. I couldn't find a parts diagram for the final drive, so I have no idea what this is, but it looks like it's supposed be a trust washer that is located at the end of the needle bearing in the center of the drive.
You can see here there is metal smeared on the shoulder of the flange and there is some blueing from overheating visible too.
So this drive is toast. Too bad as the bevel gears actually look very good. This was a 32/11 drive with a ratio of 2.91. It's one of the tallest rears BMW made (I guess the R100S was supposed to be a powerful long range highway cruiser.) I've decided to replace it with a used 32/10 (3.20 ratio) unit off a '73 I found on eBay. This will screw up the speedo drive ratio, but who cares? Bonus is the brake pads are included - I hope they're good enough to use.
Rolling Pin Rescue
My sister-in-law found a rolling pin at a Salvation Army about 30 years ago - spending the outrageous sum of 50 cents on it. It's grown to be a coveted possession and is critically integral to our Thanksgiving Day feast. It's a key tool for the creation of her magic Pecan Pies. This year, right in the middle of major heavy pie madness, the ol' girl gave out. The handle pin broke at the at the roller. We managed to get through the rest of the pie build, but a fix was needed.
This thing was old when Howie found it, so I'm sure it's seen it's share of battle pie. From the looks of the remaining pieces, the pin was actually pressed into the end where there are 4 pieces of wood set like wedges to hold the pin. Although that's what it looked like, I wasn't sure and I was unable to do much with it anyway.
I decided to try to get the broken part out first. It measured about 0.5", so I rigged up a way to hold it on my drill press and went at a bit undersize with a 29/64. Just as I was getting to the final depth, VOILA! the broken piece just came out!
- I tried to get the 4 "wedges" out, but got no where. I could have simply made a new wooden pin, but I knew I couldn't match the end of thing. So I decided to create a hidden fix that would be strong enough to stand up to another 30 years of pie making.
I decided to use a couple of pieces of stainless, one - a shaft to go in the end of the rolling pin and stick out. Then another, thin walled sleeve piece to slip over that and provide the a place to insert the end cap.
I ordered a couple of bits of 304 Stainless from McMaster-Carr that was close to the sizes I needed. I had to turn a bit off the OD of the sleeve and bore it to 0.510. After a bit of finishing and cutting to size, I had the pieces.
I decided to simply glue the thing together. I used some JB Weld to join the sleeve to the shaft. I then used some epoxy to glue the shaft into the rolling pin.
Once the glue had set up I cut the wooden end cap down to about an 1" and then pressed it into the end.
Looks to me like it's ready for battle!
Renishaw TS27R Toolsetting probe
I've been wanting a tool setting probe for my mill for a while now. It makes changing tooling a no brainer and also allows for high accuracy. These things are expensive however, so I watch eBay. After over a year of waiting, one came up for sale for $80. I went for it in spite of 3 strikes against the eBay add -
It was covered in a rusty dust and had a very funky protective flexible conduit attached. I removed that and washed the whole unit. I inspected the flex seal in the nose and everything looked really good.
The next thing to do was to test the contacts - I hooked up the DVM and tested the Red/Blue pair. Everything looks fine.
Looks like I got myself a probe.
Now all I need to do is source a waterproof conduit and the fittings to seal to the probe, mount the probe, run the conduit, mount the interface card, figure out where to add the probe signals to the machine I/O and calibrate and test it. It'll take weeks, but I'm pretty interested in getting it in.
I've been going through the rest of the bike now that the engine is sorted. Making some progress in cleaning stuff up.
Not so great news in the form of lots of metal fragments stuck to the magnet when I drained the transmission oil. I didn't take a picture, but it was more crap than I'd like to see. Nothing big or or chunky, mostly dust like with thin flakes. Probably the gear faces.
The final drive was worse. Way worse. Big chunks of metal came out, including something rather significant. This really should be rebuilt, but not by me.
It appears Uncle Ben was not too up on maintenance. The engine, trans,final drive and tires all showed signs of lack of attention. I expect this bike was just never serviced and ridden hard.
Got the new rod bearings. When I was cleaning the rods, I noticed some bluing on the big ends at roughly 12 and 6 o'clock. Musta been bad in there at one point. I'm completely ignoring any of this sort of thing...
Pretty close to being complete!
In keeping with my strategy of getting the engine squared away before any other work, I finished the engine and rigged up a test stand.
So it seems to run well enough, no weird noises, leaks or other red flags. That gives me the go ahead to start working on the rest of the bike.