Tag Archives: 1972

BMW clutch plate with flat head screws.

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When i took the transmission out of our donor bike (the one with the broken rod), i was a bit surprised when i saw the clutch plate screwed in with flat head screws. Typically they have hex-head screws. I guess BMW did this on the /2 models and some of the bikes leading into the very early 70s. Seeing this also made me wonder if this bike was still on it’s first clutch, 40 years later.

R75/5 engine. Clutch plate with flat head screws.

I tried like crazy to get these screws out. I tried with big screw drivers, screw tips in a ratchet, an air impact drill…and i got nowhere. Only frustrated.

I ordered an impact driver set that comes with a thick flat-head screw bit.
I twisted the driver while whacking it and it took 3 screws out very easily. The other 3 put up a challenge… so out came the propane torch. The the 4th came out easy. The 5th took a bit more work… and well, the 6th…it gave me a nasty blood blister but i finally got it.

I probably spent a total of 1.5 hours or more removing this freaking clutch and flywheel. But i loved every minute of it.

Fender Trimming

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While i was cutting up the headlight ears, i figured i might as well start trimming and fitting the fenders.

I hope to add some sort of rear fender under the seat to protect all the road grime and pebbles from getting kicked up into the engine area. On one of the donor bikes we acquired, the rear fender had the typical cracks where the mounting points are. But that damage was at the rear mounting points. I’m glad i held onto it because i realized that the two front mounting points have good fiberglass still. I cut the fender down and started fitting it under the seat and with the battery relocation kit.

Typical fiberglass crack on these old fenders.



Nice and whole.


Chop Suey!




It breaks my heart to cut up a brand new fender like this… but i definitely don’t want or need the massive size of the stock fender. So… off goes a few inches. I’ll let the person who preps this for paint do all the clean up and round the edges.

Front Fender custom made for me! Thanks to the guys at Boxercafe.com


Chopped up. The edges still need to be rounded and cleaned up.




Front fender with a test racing stripe

Photos of the rear fender mounted on the bike to come… I still have some trouble shooting to do with the cafe seat…

San Jose Triple Clamp Preparation

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I received a San Jose billet machined upper Triple Clamp the other day. I also went on e-bay and got some headlight ears without the giant holes in the side for the reflectors commonly seen on the /5 BMWs. I believe these headlight ears are from a mid 70’s /6 bmw.
The solid-sided headlight ears will definitely be a cleaner look.
In order to adapt the much more rigid, and better looking fork brace, about .65 inches need to be trimmed from the top of the headlight ears.

San Jose Upper Triple Clamp - My other one is equally scratched. But looks better/or worse at certain angles. It must be the machining process. I don't think i want to powder coat this. The bare alloy looks nice despite the scratches.




Headlight ears and tripple clamp. The ear on the right shows the trimmed piece. The ear on the left illustrates the line for cutting.




I did a quick silver rattle can spray of the headlight ears and roughly threw together the front end to test fit everything.
Also, most aftermarket handlebars are 7/8 sized bars. BMW bars are 22mm which required shaving out the inside of the handlebar clamps for a better fit. Everything seems to fit nicely. She’s gonna be one fine silver beast.

Test assembly of the forks, triple clamp, headlight ears, and handle bar clamps.

It feels like Christmas. New rims and mufflers.

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Not to much build progress has happened on the Cafe bike lately.    However, i have gone on a bit of a shopping spree.

In the mail, i got some pleasant packages from across the pond in Europe.

The gentleman i am building the bike for wanted to steer clear of all the traditional exhaust.  I couldn’t agree more and wish i could take credit for his idea.  Though it will complicate the build process, i am more then willing to take on the task.  After some hunting, we discovered some pipes from a R12 BMW motorcycle.  The R12’s were made in the 30s and 40s by BMW… and have completely different dimensions of a 70’s BMW pipe size and mounting region… but adapting it is all part of the fun!

Vintage Exhaust from a VERY old R12 BMW

But then the mother load came!

box from england... oh boy...

nice wrapping job! definitely like chirstmas!

Wheels!  Wheedo!  I ordered a set for my bike too (one rim is back ordered)… and hot damn, they sure look SWEET!

TASTY!

Yep! That's what we ordered. Spain's Akronts... via England.

I can’t wait to lace these on some clean, powdercoated hubs.  this bike is going to look so tasty. the wide shouldered Morad / Akront wheels are definitely the vintage, bad ass touch…

BMW Airhead Clutch and Flywheel Removal on the Cheap

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It’s been about 5 years since i have pulled a flywheel and a clutch from an airhead engine. I do remember the process being slightly ‘dangerous’ in that if you don’t remove the clutch properly, the force of it could cause harm to yourself or your motorcycle.  I don’t have the BMW ‘special’ tools at my disposal to do so safely… so i figured i would make my own. Total cost – $10 from my local Ace Hardware store (which happens to have the best spare bolt, nut, screw selection i’ve ever seen).
No need for the BMW Special tools.

Clutch Removal

You will need to purchase three M8 x 1.00 thread (fine thread) bolts about 2 inches long.
i also purchased a small piece of aluminum tubing that fits around the bolt:

M8 x 1.00 bolts and aluminum tubing. Bolts cost $1.50 each(damn pricey metric fine thread bolts)and tube was $2.20

 

The first step is to remove every other bolt on the clutch disk that secures it to the flywheel:

I cut the aluminum tubing into three sections about 3/4 inch.
Then screwed in the 2 inch long bolts with the tubing on it into those every other holes:

Bolts with spacers on them

The reason for the bolts with the spacers is to safely alleviate the pressure into a ‘second’ stage.  When you remove the three remaining ‘factory’ bolts, the disk’s pressure releases itself outward, safely, onto the spacers:

Clutch pressure now lessened and on the bolts with the spacers.

Now it is simply a matter of removing the remaining 3 bolts, evenly, until the clutch disk is released.

If your bike has these spacers, Keep them! Some clutch disks don't.

Clutch bits, friction plate, etc...


Flywheel Removal:
To remove the flywheel, you have to prevent the engine from turning while removing the flywheel bolts that secure it to the crank shaft.
Also, without securing the flywheel, you can also run a risk of knocking the inner thrust washer (around the camshaft) off the pegs within the inside of the engine block. SERIOUS damage could occur within your engine case if that happens.

BMW recommends a ‘special tool’ but it is merely a device that locks the flywheel in place.
I made my own from a piece of steel for $2.00.

12" piece of steel.

After some quick cutting and drilling, I have my very own version of the ‘special tool’.
Use the original flywheel bolts, and finger tighten them as much as you can and you are now free to use a nice breaker bar, a 17mm socket(i think) and crank out those flywheel bolts.
Some suggest using a center punch and making a small score on the crank shaft and another on the flywheel so you can put the flywheel back in the exact same position and your TopDeadCenter mark is still accurate.  Using a permanent marker might do the trick for a short term solution.

Piece of steel, cut and drilled out to prevent the flywheel from moving.

That’s it!  Now that the flywheel is removed, time to send it off to get lightened!
Another note while the flywheel is out… some people put white paint on the timing marks so you can see them better when timing. Just a tip….

Oh… and remember to THROW AWAY the 5  flywheel bolts. They are torque specific bolts and once they are torqued to spec, the can’t be used again. If so, they may wiggle back out and cause some SERIOUS damage.

For more info on clutches and flywheels, look here:
http://bmwmotorcycletech.info/flywheelremovalwarning.htm
http://bmwmotorcycletech.info/clutch.htm
Measure your clutch parts – http://w6rec.com/duane/bmw/clutch/index.htm

Northwoods airheads sells a $4 crankshaft blocking bolt to prevent the crankshaft from moving forward when removing the clutch / flywheel.
it is located here. http://www.northwoodsairheads.com/Tools.html

BMW 2002 Mobile Tradition Restoration Video

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Talk about a restoration done the right way!  It helps if you are the guys who originally designed the car!




 

Their spare parts warehouse is my version of a candy store.



 
After parting out one of these last summer, and spending countless hours working on my old 2002, and current 2002, i can say that all the parts look very familiar….

This is about as ‘brand new’ as you can get. I wonder how much they want for it? ha ha…