Kat Dash BMW /5 LED upgrade install

I had a wonderful opportunity of installing a Kat Dash /5 LED kit on my customized California blue 1973 R100/5 (yes, it is a /5 with a R100 engine) .

I had the headlight apart already to tighten up the custom key assembly that started turning inside the headlight bucket when I turned the key.

A nice small, tidy box containing the kit arrived in the mail.

The bulbs are labeled nicely in baggies with stickers that indicate the bulb color. I wasn’t sure what the wiring was for and then read the directions and figured it out.

Side note – This bike has the custom key seen here (not a typical /5 nail style key) and LED turn signals that required I wire in resistors to create more  load to activate the turn signal relay.  And, I decided to adapt all the wiring to a /6 style relay board. It all makes sense to me…

But here is what the headlight bucket looked like when I opened it up (spaghetti anybody?).
The gold things are resistors I had that were wired along with the LED turn signals.
One lead of the resister was wired with the positive lead of the turn signal and the other lead of the resistor was wired with the same ground as the turn signal.

R75/5 headlight wiring with /6 Relay board

The Kat Dash kit is pretty easy.
Follow the directions.

BE CAREFUL not to twist the LED’s in the bulb housings too much.  They will come ripped out of the bulb base if you do.

A few things to realize – There are additional wires with resistors added to allow the Generator/Voltage light to activate with the LED bulb.
The same goes for the Turn Signal indicator Light.

I got half way through my install when I hit a major problem – one of the LED lights popped out INTO my speedometer!  Yikes!  This was not any fault of the LEDs.  It had to do with the bulb base being worn/bent too much to hold the bulb in place correctly.  I had to take everything apart, remove the speedometer, and spend about 10 minutes with a tiny magnet until I was able to fish the light out of the speedometer’s rear bulb housing area.

If the bulb sits crooked in the wired base, FIX it before you install it into the speedometer.

With my 4yr old’s fingers to help me with the photo, I was able to fix it with a dental pick and bend that lip out to catch the bulb better, and hold it straight in the housing… and most importantly, not eject the light into the speedometer housing!

I continued my assembly, and to my surprise, after I wired in the relay to allow for the new LED turn signal indicator bulb to work, I no longer needed my big gold resistors in my wiring scheme.
Kat had sold me an electronic turn signal relay that works with LED bulbs and I ended up not needing it.

Here is the bike off:

Bike with the LED running light on:

Bike with the LED lights on – So bright the gamut of the camera could not capture them:

And a video of everything working:


1978 BMW R100S Restoration

A 1978 BMW R100s fixed up and released back into the wild.

This bike is an absolute dream to ride. It runs amazingly smooth.

I had to go through some serious DMV hoops to get the salvaged title status back on the road with a deadline of 5 months until I incurred DMV penalty fees.  I made it to the registration day with 2 days to spare.

I cleaned, restored, replaced, rebuilt whatever it needed to get it back on the road.  The front end is from a spare R90/6 that I had lying around.


1978 BMW R100S with R90/6 front end. by Josh Withers
1978 BMW R100S with R90/6 front end.  by Josh Withers
1978 BMW R100S with Oshmo emblem by Josh Withers
1978 BMW R100S with R90/6 front end.  by Josh Withers
R100S Straightened in frame jig
Powder Coat
Steering Race installed
Steering Bearings
Steering Bearings
Assembled front end
Forks Rebuild with new fork seals and all the goodies
Reinforced rear frame tab for passenger pegs and muffler hangers
Powder Coated and Reinforced rear frame tab for passenger pegs and muffler hangers
Swing Arm Bearings installed
1978 BMW R100S with R90/6 front end. by Josh Withers

Boyer Brandsen Electronic Ignition in 1979-1980 R65 Points Bean Can install

1980 Red R65 BMW

1980 Red R65 BMW

Although the directions are fairly clear, I went looking online for some installation help while installing a Boyer Brandsen electronic ignition on a R65 BMW that I am fixing up for a friend.

So… here is my install procedure.  I am open to suggestions or tips but this is how my install went.

The carbs were tuned nicely before doing this install. The idle never seemed to get low enough which might indicate ignition problems, or tight valves but the valves were adjusted to spec.
I might suggest you get a spare bean can to perform this on.  You end up modifying the original can  somewhat and it may be difficult if you ever want to go back to stock.


Boyer Brandsen Micro Digital ignition system.

Boyer Brandsen Micro Digital ignition system.

I purchased this from Moto Bins in the UK and it arrived within a week.

Of course, you want to disconnect your negative cable from your battery before starting the procedure.
Gastank Removal is necessary for the wiring.
And remove the front engine timing cover.
I took the bean can cover off and front bearing before I started shooting photos.  I was too eager to peek inside the bean can and see what is in there (It is my first time with a points in a can bike).


IMG_9299I then removed the bean can from the bike.

R65 Timing cover removal

R65 Timing cover removal and removal of the ignition can.

Removed points in can 1979 - 80 BMW ignition system

Removed points in can 1979 – 80 BMW ignition system

The large circlip needs to come out to disassemble the internals of the can.

The large circlip needs to come out to disassemble the internals of the can.

The points come out easily and then you need to remove the points base plate.

The points come out easily and then you need to remove the points base plate.

Notice the ‘e’ circlip on the center shaft.  Put a rag over the can when you remove that clip just in case it tries to go flying across the garage.  The rag might catch it.

Points base plate removed

Points base plate removed.

The cam has to come off the shaft and you then need to remove the springs to slide off the contact breaker unit.

Circlip removed from the center shaft. The cam has to come off the shaft and you then need to remove the springs to slide off the contact breaker unit.

After you get the center cam removed, be careful with the very small circlips that hold the bob weights.  Those need to come off to get the bob weights off.

Bob weights and center cam removed.

Bob weights and center cam removed.

Now it is time for assembly of the electronic ignition!

This was the first hiccup.  The magnetic rotor does not fit into the housing properly without bending the spring mounting tabs.  They are not easy to bend so it took some work.

Prepping for magnetic rotor install

Prepping for magnetic rotor install

Note the next photo.  The tabs have to align with the notches where the tiny circlips were. The new rotor should sit flat, spin freely and the large clip should secure it to the center shaft.

Magnetic rotor installed

Magnetic rotor installed

Another small snag.  When the stator plate was installed with the cord going out the square hole, and the mounting screws were tightened, the magnetic rotor would not spin freely.  It was a head scratcher in which everything was taken apart, put together again a few times.  Finally by rotating the stator plate 180 degrees and making sure everything spins freely before securing the mounting screws, it happily went together.

Install of the stator plate

Install of the stator plate

Stator plate with cable going out rubber grommit hole vs square hole.

Stator plate with cable going out rubber grommit hole vs square hole.

Now it is time to install the can back on the bike.  IMG_9317

The very large circlip went in and the center bearing plate installed.

The very large circlip went in and the center bearing plate installed.

I removed the diode board so I could route the wires behind it.

Removed Diode Board for wire routing

Removed Diode Board for wire routing

Control unit tucked and strapped to the frame components.

Control unit tucked and strapped to the frame components. It seemed like a tidy place to put it between the two coils.

The green wire connects with the existing green wire terminal on the rear ignition coil.
I also connected the ground wire to the coil mount bolt as well.


Not photographed but I made about a 12inch extension wire to connect the black wire from the ignition unit all the way to the other coil to replace the wire on the terminal that was connected to the old points condensor. For some reason, they put shrink tubing on the wiring as if they all connect in the same vicinity.  It was either make an extension wire, or cut up the clean tubing so the black wire could reach over to the other coil.

It is all wired up and now time to set the timing.
I am not used to these flywheels so timing it took a bit of back and fourth.  There is no ‘F’ mark on the flywheel.  But there is the OT and a Z-dot.

Once I got it timed, and I fussed with the idle a bit, it ran great.  Really smooth and more responsive then before.



BMW R90/6 Rear wheel bearing install

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.

Airhead center stand rehab

Anybody who has ever owned an airhead from the 70s has most likely come across a broken center stand tab. The problem is that after the stand gets kicked down, most people put their foot on the tab, and not on the center stand when they lift the bike up on the stand. And, over time, the thin kick tab, and the weak weld eventually gives out.
Most people have fixed it by welding part of a nail back in the same area as the original kick tab.
I think this is one of those things BMW could have made better… so i improved upon the original design.

Click the photos for larger versions.

Here is a photo of an original center stand (taken of my 1977 R100s):

Of course, i didn’t take any photos of this particular center stand before i started the project…. dough!

Center Stand repair job:

Clean up:

****EDIT This new tab might interfere with your stock side stand. I do not use a side stand on my cafe bikes so I can’t say for sure.

BMW Airhead Clutch and Flywheel Removal on the Cheap

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:
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