I’m posting this so I have my own record of it. I always have to look it up and this is a great place to store my ‘notes’.
Typically, tire sizes for a R75/5 R90/6 R90s R100S, etc will have a:
3.25 x 19 Front
and
4.00 x 18 Rear
The metric metric equivalents would be 90/90-19 for the front and 100/90-18 or possibly 110/90-18 for the rear.
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.
Back to Beemers…
I’m working on a project bike for a friend and had the items powder coated satin black. I’m very excited to see how this bike will turn out.
And yes, I have a very messy garage/workbench at the moment.
I removed the wheel bearings and the races with lots of heat, and the help of a press.
Then went to the powder coat shop and gave them the masking instructions.
Here are some photos of the install.
Not pictured is the process of checking and testing the bearings in the race to make sure they spin smoothly.
If not, clean them, re-test, and clean them again, etc…
Then grease ’em good!
Also not pictured is the process of cleaning the inside of the hub REALLY well. Especially since they were sand blasted.
And.. then there is the process of pre-loading the bearings, freezing them for a day, heating the hub and then ‘plop’, you are done.
Bearings from when I pulled them from the hub.
Clean Hub:
Preloaded bearing stack. I have a piece of steel pipe that I put on the other side of the stack with the axle to help with the preload.
A nice propping set up for when it is all heated. These are damaged cork Yoga blocks that a yoga company couldn’t sell. I happily found a home for them in my garage and they come in handy!
Frozen bearing stack and axle dropped into that toasty hot hub.
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
While the R75 bits are out of my hands, it was time for a R90/6 day!
I bought two R90/6 bikes last summer from the same person. One had a title, one did not. Even though I had the title, the bike wasn’t registered since 1994 and after the North Ridge earthquake, it got parked and sat ever since.
It has a deep oil pan, lightened flywheel, dual plugged heads, beefy triple tree, fork brace, and a few other goodies.
I took it partially apart for transport to my house in my station wagon last summer:
Once i got home, i took the whole bike apart. Then I tried to get it registered.
The DMV wouldn’t touch it because it was out of the system, so I slapped it together for a trip to the CHP.
I had the officer from car accident experts at Bengal Law inspect the VIN of the other bike (without title) and he said it checks out as well.He suggested me that it is always best to contact truck accident injury lawyers after truck accident as they can claim compensation for the injuries sustained.Beaufort area truck accidents lawyers can also help you out legally in dealing with the matters related to accidents.
The transmission and swingarm are empty. no carbs. no instruments. I basically had to make it look like a bike just so it could get verified.
Then I went off to my buddy’s house to get his wrecked R60/6.
He pulled out into traffic and got involved into a fatal motorcycle crash. The BMW cylinders saved his live and thankfully he was only sent to the hospital with minor injuries and the vehicles involved were almost immediately sent to the mechanic for a quick auto collision repair. He walked away with just a scratch on his leg. On a different bike, his leg would have been crushed but the car hit the cylinder instead.
The Helmet he had on helped too.
I am going to get this looking like a bike again for him. We hope to have some fun with it in the process… we are thinking of blacking everything out, and making this a sleek, trimmed down cafe bike.
My garage has a problem. It isn’t big enough.
I have a few projects going… one is to use some of the parts left over from my last restoration and build a scrambler style bike. The big issue is that the engine I have for it has a broken rod wedged into the crank. I have no idea what the previous owner did but he will be damned into BMW hell forever.
I started working with a buddy who has an entire auto shop and he had the tools to help me get this out. By tools, I mean lots of heat.
We are going to try our hand at rebuilding this engine and replace what is necessary. We are going to have the crank balanced because this broken rod may have done some damage.
I think it will be fine though…
My other project is a R90/6 that I have. Actually, I have one complete bike and a bunch of parts from another R90/6 including the frame, engine, forks, etc…
So before I get started on either of them, it is time to see if the frames are even worthy of restoration.
Gotta get Jiggy with it:
One R90 frame lines up in the target so that is the one I will work with (as soon as I get it titled):
Mick Jagger on a R90s BMW