Tag Archives: 1972

Transmission Install

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A Transmission install is actually not difficult.

Step #1 is making sure the swingarm is unmounted from the frame. It can remain connected to the shocks.

I then took caution to protect the frame:

Protection. Notice the rags too:

Time to prep the transmission. It helps if the shifter and the clutch arm are removed. In my case, i removed the shifter but left the clutch arm mounted:

Time to lube the splines. Make sure the splines are clean of dirt and grime. I use a BMW moly grease. It is sticky stuff. :

Keeping the swingarm and rear wheel pulled back, gently lift the transmission into place. It may take a small wiggle here and there to get the splines to mate with the engine.

Make sure the top right bolt of the engine housing aligns properly with the transmission housing as you mate the splines into the clutch:

Time to tighten everything down.
You need a M8 nut and washer for the top right engine stud bolt.
a M8 x 40mm bolt and washer for the top left mount. (Note, i am not installing the BMW airbox. If i was, there is a retaining clip that mounts to the top left bolt along with a washer intended for the airbox).
a M8 X 85mm bolt, washer and nut for the bottom right mount
and a M8 x 40mm bolt and washer for the bottom left mount.
A 6mm hex socket and wrench does the trick along with a 13mm wrench/socket.

Lastly before you mount the swingarm, Make sure you attach the driveshaft boot. Notice the different ends of the boot. The round end is for the transmission, the oval/rectangular end is for the drive shaft.

Next step… aligning and mounting the swing-arm… stay tuned!

Starter upgrade

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A while back we ordered a new starter from Euro Moto Electrics.
It weighs half as much as the original BOSCH starter. About 6lbs lighter to be exact.

As a result, it doesn’t require the rear mounting bracket the heavy Bosch starters need (#2 in Photo).
The starter itself has threads where it connects near the flywheel so no need for the original nuts. You simply install the bolts from the flywheel side, and tighten the starter to the engine housing.
I plan on keeping the extra plastic cover and wire ring that holds it in place (#10 and #11). It will help keep some of the clutch dust contained.

Skateboards make good dollies

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…and wives help when needing to hold it from rolling down the driveway…
And she kept me from breaking my back by trying to lift it out of the trunk by myself.

Dave Gardner at Recommended Service did the assembly.

I can’t wait to fire this thing up…
Siebenrock power upgrade Pistons and Cylinders.
Lightened Flywheel.
Newer oil pump cover.
New BMW valves and valve job.
/6 rockers.
Stainless pushrod tubes (as part of the Siebenrock kit).

Wheels Laced

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The owner of the bike had a good suggestion. At first i wasn’t too into the idea but now that I am seeing everything come together, I really like it.
He suggested that we powder coat the hubs in white:

We are going with some wide shoulder Akront/Morad rims. I can’t wait to see these on the bike.

I took them to Johnson and Wood in North Hollywood to get laced. They bought the spokes for me and laced them for a very affordable price and a reasonable turn around. I’m surprised when I receive responsive and courteous customer service these days and the wheel guy, Al, was great to talk to. He and I traded a few faxes and phone calls talking about the proper offset. He was proud to give the wheels back to me and offered to re-adjust the offset if i felt that anything seemed incorrect.

Test fit and I’m dying to get some rubber on these dubs.

Rub a dub dub. New Battlax BT45 Bridgestones ready for the roads!

Took Apart and Cleaned the BING carbs

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These are the 64/32/9 and 64/32/10 BING carburetors. They were standard issue on the R75/5 BMWs back in the early 70’s. From what Siebenrock says, they will work just fine with their power/performance upgrade piston/cylinder kit. They may need different jetting but I’ll cross that bridge when I mount them to an assembled engine.

I finally got around to looking into them. Holy crap, they are used and abused. I have two sets, one from the parts bike and another from our ‘main’ bike.
One set has been modified by a previous owner who added vacuum ports on them. The ports look bad, and who knows if they are completely sealed so i’m going to shy away from using that set of carbs. Too risky.

The other set is nasty but can be rebuilt. The diaphragms are OK but everything else leads me to believe they have never been rebuilt before. The only drawback to using these carbs is that the BING nameplates are trashed and replacing them is a tricky job that requires precisely drilling out each metal nail. It may require many hours and machine work that I’m uncertain about. I’m thinking that I will polish the crap out of those plates instead.

Here is the carb, dirty and ready for a new life:

Here goes:

Choke removed, needles coming out:



Everything apart (an unofficial diagram):

The second carb had a slight issue… One of the butterfly screw heads turned to putty and stripped when I tried to remove it. I had to drill it out, and bastardize some parts from the second set of carbs to replace the pivot arm that the butterfly attaches to.

I was lucky enough to receive an Ultrasonic cleaner as a gift earlier in the year. I LOVE the idea of NOT using a highly chemical, messy, toxic carb cleaner kit. So I poured a bit of simple green in the tank, a small dab of laundry soap and some hot water.

After about 20 minutes of vibrations, the carbs came out nice and clean.
Before:

After:

Next steps:
Time to buy the complete BING rebuild kit for $210. And maybe blast these carbs for an even cleaner surface.

Built a battery bracket

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Got the Shorai battery and luckily it fits under the tail section as I had hoped. It only weights about 3 lbs so it shouldn’t be a weight issue. It will just be a matter of running the wires in discreet places.

I bought some aluminum to make a cage and bracket for it.

I cut the two ‘L’ brackets to create bumpers from preventing the battery from moving forward or backward.Then started bending the aluminum strip to make a srtap like bracket to hold the battery from moving left/right or uo/down.

I marked the footing and drilled some holes. I purposely offset the bracket to not interfere with the outlet on the battery for the Shorai battery tender.

Done