Disassembly of an airhead R75/5 BMW final drive

Here is a photo essay of sorts detailing the disassembly of a 1973 BMW Final drive. The same applies to all 1970’s era BMW’s (R90 R100 R75 R80 /5 /6 /7 S etc). The seals were shot inside causing leaks. The splines are decent so no need to weld on a new set of splines. I plan to have the drive blasted and powder coated to match the rest of the bike for an upcoming build.

The image descriptions have notes on the disassembly.

Reinforced Passenger Peg Muffler Hanger tab on BMW motorcycle

This is one of those things I try to do to every BMW motorcycle I rebuild.

The Motorcycles Cushman Truckster is one of the more popular models of bikes in the United States. It has been around since the mid nineteen-hundreds and has always been a top seller among collectors and bike lovers. While it doesn’t come with a warranty, you can get around that by getting a Cushman Tribute package, which pays for repairs or parts that might need them in the future. There are many sources online for Cushman bikes, including parts selection, prices, and even complete restoration packages for your bike if you’re not sure what you want to do with it. When you buy this bike, be prepared to spend a little extra money up front to purchase the bike you want. But remember, it will end up being cheaper in the long run because of the extra care you’ll be taking with it.

It is almost never the engines in BMW`s that are the problem; properly serviced with clean oil at regular intervals, and no abusive riding, they should easily see 200,000 miles

This area is cracked on nearly every frame I tear down. It is the rear foot brake area which also is the muffler / silencer hanger, and where the passenger foot pegs attach. This frame is a 1978 BMW R100s. If you are considering rear sets on your bike that attach to this section, then I HIGHLY RECOMMEND doing this procedure.

cracked tab near rear foot brake pivot hole on BMW airhead framecracked tab near rear foot brake pivot hole

cracked tab near rear foot brake pivot hole on BMW airhead frame

New piece of metal to weld onto the old cracked section to reinforce the area making it MUCH stronger and no longer prone to cracking.

Welded metal onto the rear foot brake section of a BMW R100S

Finished powder coated frame with the welded metal. This area is out of sight to most people unless they take the rear tire off.

Check out Oshmo.com

Just an update… I have 3 bikes in the works but they have been taking longer then expected.  I’m trying to customize many features vs buying the available parts out there.
And, I’ve been busy over at Oshmo.com helping to develop some Airhead aftermarket parts that look good, and function, for customizing these old BMW’s.

Recent additions are rear sets, and top clamps…  more ideas to come!!

Black Rear Sets for 1970's BMW motorcycles

Black Rear Sets for 1970’s BMW motorcycles

 

 

Ed Korn Cycle Works Swingarm seal removal tool

Removing these seals is a frustrating process.  Prying them out usually doesn’t get you anywhere.

I bought Ed Korn’s tool a while back and it can be used for pulling both the races, and the seals.

Here is how you use it to pull the seals.

Here is the tool assembled

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I first cut out some of the seal’s rubber with a razor blade.
It was easier to get the tool installed that way.

 

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Then you tighten the threaded rod with the allen fitting at the end of it.  By doing so, it expands the nut against the screws and presses them outward so they ‘catch’ under the metal part of the seal.

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Then you install the collar, plate and washer and nut.

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Once you begin tightening that nut, it will pull the seal out into the collar.
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You can then loosen the nut, and break the old seal free with a few taps with a hammer.


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The new BMW R90S Concept bike

I was just having a conversation with a buddy 2 days ago about how BMW should ‘remake’ one of their old bikes.
Triumph did it with the Bonneville. Ducati has the Paul Smart bikes (which i love).
Well, here it is. The homage BMW R90S.
The original R90S is a true classic.
While the new bike looks amazing… i fear that it looks too much like a new bike and not enough like a classic.
Of course, i’d still love one in my garage….