Hi,

I'm in the midst of converting my 1988 K100RS which I've owned for nearly 13 years into a K100RT plus more. Story is that I've always wanted an RT but at the time I was in the market for a motorcycle, there were no RTs available. So, I bought an '88 K100RS instead. It was a compromise in my desires. I was very naive about BMWs at the time. Shortly after buying the bike, I was informed by the service department at the local BMW that my front end was not an RS front end and they weren't sure what it was. Investigating further, I found out that one of the previous owners had really gone over the bike, changing many things including replacing the K100 forks, brakes and wheel with a K1100 front end. Wiring was different as well. I guess this was a Franken-bike.

I lived with the beast but never really loved it like I should have since it wasn't an RT. Fastforward to this year. I met a local chap through this forum who was looking for an RS fairing to convert his RT into an RS. I wanted an RT and had an RS I wan't so in love with. Match made in heaven ... we traded fairing parts. So, now I'm sitting with a garage full of RT parts and a very naked bike.

A little side story now. The rotors on my K1100 front end were aftermarket and needed BADLY to be replaced. They were worn past the factory recommended minimum thickness and the floating disk was very loose. So, I bought new K1100 rotors. This lead me down the path to see what was involved in replacing the K!00 calipers with K1100 calipers. I acquired all the parts for the swap-over from 2-piston to 4-piston. So, they have been sitting in the workshop for several months in anticipation of a changeover.

Now is the opportune time to do everythnig and I thought I'd keep a small diary of my progress in this thread.

Status as of 1 June 2010: I disassembled the bike and removed all of the parts of the RS fairing that I planned to trade. I received in return all the equivalent parts of the doner RT. I have cleaned and degreased all the RT parts, removed all hardware, and gave all the parts to a local painter for painting. The remainder of the bike parts are lying on the garage floor in a heap (suitably marked for reinstallation). The Bowden cables for the RS are shorter than the RT ones so I ordered the RT cables so that the controls can be mounted on the longer RT bars. I'm waiting on parts delivery and completion of the paint job at the moment. Estimated wait time is 2 more weeks. In the mean time, I'm cleaning up the bike after 22 years of grime accumulation.

Stay tuned.
- Robert

Thanks Robert and we look forward to the pics? and the end result.

Do you have 2 pot brake calipers on k11 forks?
If so could I have a pic of the nmounting brackets?
Thanks
Ray
p.s. thought about this conversion a lot during -6 and winter snow

I converted to 4 piston calipers...made no difference to braking. However there was a great improvement on fitting braided hoses.
I have since reverted back to the original 2 piston calipers.
Ajays

Thanks Ajays.
ray

"you can't get to heaven on roller-skates"

Jeez you crack me up!

The RS is a credit to you Ajays!

Ajays wrote:I converted to 4 piston calipers...made no difference to braking.

Ajays,

Your experience mirrors that of another person who posted to BMWMOA describing his experiences with converting the calipers on his K75S from to to four. The size of the standard K100/K75 rotors is smaller than those on K1100. His conclusion is that larger rotors on the front of the bike would improve the braking effectivness. What he experienced was that it was easier to lock up the front brakes and that a lighter touch on the front brake was necessary. My prediction is that my braking effectivness will improve because I currently have inferior calipers fitted to large rotors. We will see I guess.

ssray wrote:Do you have 2
pot brake calipers on k11 forks?
If so could I have a pic of the
nmounting brackets?

Yes, I currently have two pot calipers on K1100 forks. These are pictures of the calipers attached to the K1100 forks with the old after-market rotors. Those rotors are now history. There are no mounting brackets as you can see. The calipers bolt directly to the forks and there are washers to align the caliper with the centre of the rotors.





- Robert.

With brake conversions the crunch is can you lock the front wheel under heavy braking ? If you can, no brake conversion will better your stopping distance only potentially reduce the finger pressure required to achieve lock-up.
Regards,
K-BIKE

Correct K-bike. The braking effectivness ends when the tires loose grip on the road. Also, brake conversions are potentially dangerous affairs to be undertaken with caution.

<this post is removed because the tutorial on "upgrading K100 brakes to K1100 brakes" I posted in the Tutorial section duplicates this content>

Robert, excellent text and photos.

Well done!

Yes this is excellent and should be posted in the tutorial section.
Thanks for the effort.

I decided to upgrade the headlight circuit in my RT conversion because I may purchase a higher wattage headlight in the future. I know that Eastern Beaver sells an excellect plug-and-play adapter for the K100 and I did consider it. However, in the end, I sourced several parts from a local electronics supplier and built my own.

I wanted small size that would fit in the relay box under the seat so I chose hermetically sealed PC mount relays instead of normal automotive horn relays that are commonly available. I needed two -- one for low beam and one for high beam. The circuit I reproduced was this:



The parts cost was less than $10 CDN and I purchased the parts from Sayal Electronics (www.sayal.com). I used their PC mount relay JCMC-2014-1; a 20A 1FormA 12V relay, hermetically sealed, flux-resisitant. The PC board was a typical prototyping breadboard. Here are photos of my completed board:


On the left photo, the three connectors to the left are the control inputs, highbeam, lowbeam and ground. On the right, the three connectors are highbeam out, lowbeam out and power in. I used frame ground at the headlight connector end to complete the circuit. To complete the circuitboard, I will be using silicone sealant to insulate the bottom to prevent shorting within the relaybox. The board fits nicely within the space in the relay box where the accessory plug is located.

robmack wrote:I decided to upgrade the headlight circuit in my RT conversion because I may purchase a higher wattage headlight in the future.

Nice small unit. If you install a higher wattage bulb, you will have to replace the headlight socket with one made in ceramic. By experience, the heat generated by a higher wattage bulb will melt the original plastic socket.
You can purchase it here for $9.00


Have a look at the following schematic as this is the proper way to upgrade your circuit.
The advantages of this one is that you keep the original circuit as well as the original headlight socket.
In case of problems with your relay system, you can quickly reinstall the original socket.
You don't have to cut any wire on the original loom. (if get a main fuse protected positive from the battery)
You get the signal for the high/low beam relay from the original socket (insert some bade connnectors into the socket).

Crazy Frog wrote:If you install a higher wattage bulb, you will have to replace the headlight socket with one made in ceramic.

I will look into that when it comes time for the larger bulb.

Crazy Frog wrote:Have a look at the following schematic as this is the proper way to upgrade your circuit.

Thanks for the pointer, Bert. I saw that schematic before and considered the circuit. I had a requirement for small size which meant finding small form-factor relays with the current carrying capacity for a lighting circuit. This circuit requires a 2FormA "changeover" (SPDT) relay with is hard to find in a small package at 20A capacities. One other requirement that I had was the ability to install my Flash2Pass garage door opener. My circuit can accomodate the F2P very easily.

The two circuits still function the same; the diodes included in the circuit you presented prevent damage and malfunction if the connections are reversed accidently. I could have constructed my circuit as an add-on to the lamp base requiring me to unplug the lamp socket, plug in the circuit and plug that assembly into the lamp; no modification to the stock wiring harness required. Even so, I would still have to run two wires for high current switched voltage and ground. I was lazy and put the circuit in the relay box with an idea in the back of my mind to put the F2P in the tool tray.

The motorcycle is coming together ... finally!!

After a very long wait, the fairing pieces came back from the painter's. I am very impressed with the work he did and quite pleased with the results. The painter took extra effort in getting these parts ABSOLUTELY perfect. The colour is also spot on. There is a hint of purple in the metallic that really pops out in sunlight but is muted in overcast or natural light.

Most of the fairing is on the bike now. I have to take the motorcycle in for valve clearance adjustment and throttle body sync this Monday so the lowers are not yet attached. The bike has kindly agreed to share its garage space with some flooring that's being used in our home renovation project, as you can see in the picture below:


Cable Management
One big improvement I made with the wiring as compared before is in wire managment. Before, the PO had tied up all the wiring using tiewraps. Now, tiewraps have their place but they are not a substitute for proper cable management products, such as conduits, spiral wrap and corrugated split tubing. When I rerouted the wires and cables to the steering column, I used 1/2" Polyethylene spiral wrap to manage the tangle of wires. This is pictured below:

Spiral wrap works much better in this application than does corrugated split tubing.

Corrugated Split tubing (as illustrated in the photo above) is a better alternative for stereo / multimedia cable management but not such a good choice for motorcycle wiring harness use. It is used on modern BMWs only because the wiring harness is inserted in the loom at the time of manufacture. Retrofitting the split tubing is problematic. Taking leaders off is a pain because the take-off point has to be tiewrapped to prevent the leader from migrating.

Polyethylene spiral wrap is easy to retrofit to existing wiring, looks good, goes on quickly, comes off quickly, is abrasion resistant and is flexible. It is possible to take leaders off of a main cable route, at any point in the route. Now, there is no pinched wires in the steering head, the wire routes through the decorative panels much easier. I recommend that you take a look at this method of taming the wiring mess, even in the harness under the tank. The wrap is cheap and ubiquitous, available at most any good electronics supply (I got mine at Sayal Electronics in Toronto).

Adding a Centre High Mount Stop Lamp (CHMSL) to the 22L Top Case

I like safety. Safety is good. That's why I decided to mount an auxillary brake light, otherwise known as a CHMSL.

I scoured the Internet looking for a company that sold spoiler brake lights for motorcycles. There were the usual suspects, those license plate mounted auxillary brake lights but I wanted a spoiler type similar to a car. I found only one who manufactured and sold such a light and that company was Mutazu Motorcycle Accessories Inc. The spoiler they sell has 16 LEDs, is aerodynamicly shaped and offers two light modes. One mode is all LEDs solid lit; the other mode is LEDs sequentially lit, forming a moving, attention getting pattern. The LED lighting pattern is chosen depending upon which way the light is hardwired. I chose the solid lit pattern.

I decided to mount the spoiler on the 22L top case as it puts the brake light at driver's eye level, making sure that they see that I am braking. This I feel is better than the license plate mounted auxillary brake lights available for motorcycles.

The mounting process started with deciding where on the lid of the top case I should mount the spoiler. Having decided upon that location, I taped clear mylar sheets (used for overhead projectors) to the lid with painter's tape. I set the LED spoiler on the case and drew an outline around each foot.

I flipped the mylar over and marked where the screws holes were located. I returned the mylar to its original position and drilled the holes for the mounting screws and cable -- 6.5mm for the cable and 4mm for each screw hole. I fed the wire through the hole in the lid (it was a snug fit) and screwed down the spoiler.


I next drilled another hole into the base so that the wire could exit underneath the topcase. I fished the wire through and fastened a connector to the end, making sure to seal the electrical contacts with heat shrink tubing.

I used an AMP connector pair to connect/disconnect the electrial circuit between the top case and the motorcycle. I choose an AMP connector instead of the bullet connectors supplied with the spolier because there is polarity involved in wiring this spoiler up and I needed a polerized connection. I fished a wire from the rack on the tail piece down between the seat and into the storage compartment on the tail. I continued to feed the wire into the rear lamp assembly and connected it up to the brake light socket, paralleling the existing wiring.

This finished the wiring job. The light tested OK. Whenever I remove the top case, I just disconnect the AMP connector and leave the other one dangling in place.

Hi all,

It's a holiday here in Canada today. Canada Day! So, I had the day to finish off the RT conversion.

The bike is running ever so smoothly after dropping by the service shop to get valves adjusted and throttle bodies synchronized. The mecahnic also adjusted my steering. There was an incredible amount of slack in the adjuster nut -- nearly 3/4 turn. It's now much, much better. Anyway, here is the transformation.

Before. this is the bike as an RS model:



And after. This is the beast in its RT guise:







Thanks for following along on this RT conversion.

Cheers, Robert.

So was it all worth it? That was a ton of work.

club_c wrote:So was it all worth it? That was a ton of work.

Yes, I believe it was worth it. There wasn't really a whole lot of work involved in the conversion. I did a ton of research before I ventured out and tried to swap the parts, however, that is just my nature. I waited a very long time for certain gating event to clear up ... such as parts that were slow to ship and the painter who worked on the fairing as if he owned it (don't get me wrong..I really appreceiate his devotion). I learned alot about the bike by doing this conversion and tackled some jobs that, frankly, I probably wouldn't have done otherwise...I'm thinking the 4-piston brake conversion, the heater grip installation and the wire management I talk about above.

My receommendation to others who might contemplate this conversion is that don't be afraid...do it. It worked out well for me. I had the motivation to try because I always had the desire for an RT. Funny that I bought an RS but it was the market at the time and I never found a reason to sell the bike (nor a buyer considering its condition).

Cheers,
Robert.

Nice tip on the wire management! I was looking at Techflex, but it gets spendy real fast.

OG

Nice mod, I have spiwrap on some of my wiring I agree it does the job
just right.

BIG D