5 speed Neutral Switch prep work

I learned this lesson the hard way.
Apparently many of the neutral switches, when purchased new, are faulty and are prone to leaking. Not knowing this, I went ahead and installed a brand new switch into the transmission, then installed the tranny onto the bike, added transmission fluid I and started to break the engine in.
After the first ride, I realized that there was a small drip of transmission fluid coming from the neutral switch.
It would not be such a big deal on a late 70’s airhead but the engine case of a /5 is different then other airheads and requires that the transmission gets pulled back about 2 inches so the switch can be removed and replaced.

Keep in mind a few things…
•/5 BMW’s had 4 speed transmissions so this may not apply to most people. I upgraded this bike to a 5 speed.
•There are two types of switches for the two different 5 speed transmissions. They work differently. I think you can tell them apart because one has the electrical prongs facing sideways, the other has the prongs straight.

On a late 70’s airhead, there is a large spacer on the engine case under the transmission. You can wedge blocks under the oil pan to keep the engine from sagging, then drive out the rear engine mounting stud until the large spacer can be removed, then you have access to the neutral switch for an easy replacement.
(Click photo for a larger version).
R100sNeutralSwitch

On a /5 BMW, the engine block doesn’t have the spacer. You will have to take the airbox cover off, remove the swingarm, rear wheel, disconnect the transmission from the engine, etc…
While you are in there, it is a good time to lube your transmission splines and re-lube your swingarm bearings!
slash5W5speed

Here is a new neutral switch and I am going to seal it with some JB weld. You can also use epoxy or bubble gum (just kidding about the bubble gum).
NeutralSwitchimage_1c

I took some sandpaper and exacto blades and scuffed up the plastic surface and part of the switch near the plastic. After I scored everything pretty good, I cleaned it up with some acetone. NeutralSwitchimage_2C

I mixed up a batch of JB weld and coated all the plastic and part of the metal. I may have went overboard but better safe then sorry. I don’t want to have to replace the switch again.
Allow for at least 24hours to dry.
NeutralSwitchphotoCoated

Now it is time to drain the transmission oil, pull the rear of the bike apart, slide the transmission back and replace the switch.
This could be a 15-30 minute job on a R100S. Unfortunately it will take much longer on the /5.
Don’t forget to buy new crush washers for the transmission plug, neutral switch and transmission fill plug. They are only a few extra bucks.

Gascap cork replacement

Unfortunately, BMW only sells new chrome /5 style gascaps with the lock mechanism. I really like the smaller look of the non locking gascaps. I sourced a very good condition aluminum gas cap and unfortunately, the cork gasket is worn.

oldcork

Luckily, BMW does sell replacement gaskets. I happened to have one in my parts stash, brand new. What I needed to order was a new retaining pin and washer from BMW.
Removing the old one was difficult. I started by shaving the old pin head down with a dremel. By doing so, i was able to remove the old cork gasket and create a flat surface to align a drill bit to drill out the old pin.
disassembleCap

I then took the gas cap to my drill press and tried to center my drill-bit as best I could to drill out the old pin. Unfortunately, the drill bit took on the path of least resistance and did not center perfectly to drill out the old pin. And, the old pin’s metal was either extremely hard, or it got hardened from all the heat of the drill bits.
It was one of those jobs that took an hour longer then I had anticipated.
I eventually got it drilled out. Here it is with the new gasket, pin and washer:drilledout2

I used some JB weld in the old pin hole to fill the area where my drill bit went awry. I then drove in the new pin by tapping it down with a hammer.
She’s now ready for fuel.
Gascaplr

/5 BMW Speedometer Wiring

Hopefully the following wiring photos can be of help to somebody.
I hope to add to this post once I am done.
Click on the photos for larger versions.

On my last /5 build, I adapted a /6 relay board to my /5. I cut off the terminals i did not need due to the simplicity (and less features) of a /5 vs /6. I also liked the idea of having the fuses easily accessible. Everything works great however in hind sight, I maybe went too far (did I complicate a simple /5 wiring scheme by adding the /6 board?) and perhaps I left the fuses too exposed where they could get knocked out. But I have over 3000k on the bike right now and no issues.
The gold resistors on the bottom of the headlight bucket are for the LED turn signals. Resistors are necessary to adapt the low current draw of the LED’s so the relays still work.
The large black box at the bottom is a /6 /7 and R100S style turn signal relay.
BlueWith6
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Here is my naked speedometer. I highly recommend painting the inside of the headlight bucket a bright color. It really helps for seeing inside there.
Labeled
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Here is the speedometer wired. It is hard to see some of the actual terminals/connections but this should be a nice short-cut for somebody who doesn’t want to read the wiring diagram.
Please note: My Red/Yellow wire going to the instrument lighting is also a gray/black wire in most wiring diagrams.
Wires
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UPDATEUPDATEUPDATE
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In hind sight, my /6 relay board wasn’t such a bad idea. I scoured electrical stores, auto stores and the internet for terminal relays and fuse blocks that would work for inside the headlight bucket.
I never really found the perfect solution. I was looking for a nice, compact 2 fuse relay. I also looked for a junction box that suited all the necessary connections.
I ended up using the terminal connector that came with the Rocky Point headlight key conversion (white junction on the right side of the photo).
I also used a CINCH 6 position terminal for wiring up the turn signals, brake light and other connections.

I decided to abandon the typical inline ceramic fuse holders that BMW supplies. The ceramic fuses aren’t readily available at your local auto parts store so I opted for something more common. The rubber covered fuse holders carry a typical ATC fuses. BMW specifies an 8 AMP fuse. I went with a 7.5 and a 10 (because that is what i have in my garage). The 10 will be fine. The 7.5 vs 8 shouldn’t make a difference.

The Clymer manual did a great job for most of the wiring.
The other diagrams helped A LOT though. One diagram specified which wires connect to which pin on the turn signal flasher.
One thing that none of the diagrams specify is which terminal numbers on the relays connect to which wire. Yea, a bunch of wires plug into the starter relay, but which wires go to each pin/terminal?
Luckily I took a BUNCH of notes when I tore the bike apart. And luckily the old connections were correct.
Here are my resources:WiringDiagrams
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Here is the headlight bucket as tidy as can be (for now).
WiredHeadlight2
Another iphone quality photo of the headlight:
WiredHeadlight1

After some battery charging, and some testing, and pulling my hair out only to realize that the Rocky Point switch was labeled incorrectly (blue and yellow wires were mixed up and mislabeled). we are good to go!
I popped the headlight on and the bike is showing signs of life again!

HeadlightOnCloseup

HeadlightOn

UPDATE UPDATE – – – –

Here are the photos of the second silver bike’s headlight wiring.  It looks somewhat messy in the photo but take my word for it, it ended up being tidy.  I used a cut down /6 relay board and mounted it inside the headlight bucket.  HeadlightRelayBoard_IMG_4588
HJeadlightWiring_IMG_4592

Transmission Install

A Transmission install is actually not difficult.

Step #1 is making sure the swingarm is unmounted from the frame. It can remain connected to the shocks.

I then took caution to protect the frame:

Protection. Notice the rags too:

Time to prep the transmission. It helps if the shifter and the clutch arm are removed. In my case, i removed the shifter but left the clutch arm mounted:

Time to lube the splines. Make sure the splines are clean of dirt and grime. I use a BMW moly grease. It is sticky stuff. :

Keeping the swingarm and rear wheel pulled back, gently lift the transmission into place. It may take a small wiggle here and there to get the splines to mate with the engine.

Make sure the top right bolt of the engine housing aligns properly with the transmission housing as you mate the splines into the clutch:

Time to tighten everything down.
You need a M8 nut and washer for the top right engine stud bolt.
a M8 x 40mm bolt and washer for the top left mount. (Note, i am not installing the BMW airbox. If i was, there is a retaining clip that mounts to the top left bolt along with a washer intended for the airbox).
a M8 X 85mm bolt, washer and nut for the bottom right mount
and a M8 x 40mm bolt and washer for the bottom left mount.
A 6mm hex socket and wrench does the trick along with a 13mm wrench/socket.

Lastly before you mount the swingarm, Make sure you attach the driveshaft boot. Notice the different ends of the boot. The round end is for the transmission, the oval/rectangular end is for the drive shaft.

Next step… aligning and mounting the swing-arm… stay tuned!

Built a battery bracket

Got the Shorai battery and luckily it fits under the tail section as I had hoped. It only weights about 3 lbs so it shouldn’t be a weight issue. It will just be a matter of running the wires in discreet places.

I bought some aluminum to make a cage and bracket for it.

I cut the two ‘L’ brackets to create bumpers from preventing the battery from moving forward or backward.Then started bending the aluminum strip to make a srtap like bracket to hold the battery from moving left/right or uo/down.

I marked the footing and drilled some holes. I purposely offset the bracket to not interfere with the outlet on the battery for the Shorai battery tender.

Done

BMW /5 Wheel Offset information

I took my hubs and rims to get laced last weekend. I brought an extra set of assembled wheels for reference and the guy doing the lacing said BMW’s didn’t have an offset (meaning they were “0” or centered). So i took the extra set home thinking he was the expert. However, it is a shop that mostly specializes in Japanese bikes.
I remembered reading something about there being an offset many years ago and I looked into it. It turns out that the /5 motorcycles do have an offset (because of the drum brakes and hub).
Some say that wheels with disk brakes do not have an offset but not according to the spec sheet.
I called the the person doing the lacing and he was very nice to talk to.
His name is AL and the shop is Johnson and Wood in North Hollywood.

Here is a piece of advice written by the BMW motorcycle guru Duane Ausherman:

Before you cut the old spokes, install the wheel, with or without a tire. Measure to each side of the swing arm. This will tell you just how centered it is. If you need to move it over a bit, calculate it.

Then lay the wheel down on a flat surface. If it is a drum brake, it is very easy. Have the drum side down. Now find 3 nuts that will just fit under the rim. The thickness of the nuts gives you the current off-set. Now calculate in any correction needed for the wider tire.

Now find 3 nuts of the off-set you desire. Hold the rim off the flat surface to give you the off-set. Lace the spokes in by hand and a bit at a time bring the nipples up to snug. The rim is now laced to the correct off-set that you desire. Put it in your tuning jig and finish up. As long as you do equal tightening to each nipple, the off-set won’t change.

I have done many dozens this way and it is much faster than using the BMW off-set tool.

Attached is the BMW spec sheet from 40 years ago. Hopefully this will serve as a guide for others out there who are lacing rims.