Tag Archives: bmw

update on the /5 tear down

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She’s mighty naked.  i gave her  a quick rattle can paint on the frame to get an idea of what a silver frame will look like. The wheels are out getting the bearings removed and then i will de-lace them… so i can get the hubs powder coated.  I’ll slap another set of wheels on there in the meantime.

Next on my list are:

–Trim down a rear fender so you can barely notice it yet it will protect the bike’s frame innards from getting crap kicked up into it.

–Trim the headlight ears for a Billet upper fork brace modification.

Order some rear sets and weld a reinforcement plate to connect the rear sets to (near the passenger peg location).

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