Grounded

So I have installed the new Hall Effect Sensor, set the timing and think I'm golden. No such luck, you think? Correct.  After my first ride to test out the timing settings I came back home and parked the bike. Later that day I decided to go out for a quick shopping trip and as I stopped for a light it sounded like the engine was dying again. Crap! But the revs picked up again and as a precaution I pulled over to the right side of the road and made a turn off a busy road onto a back street. Good call. As I turned the corner the engine just plain quit. Instead of the slow bogging down , this time it was a quick death. Hmm....The side street was mostly a downhill so I popped the clutch and it sorta started again for a brief period, accelerated and then again it failed.  After rolling further downhill it was completely dead. I had lights etc, but it would not restart. So I dismounted, waited and eventually it came back to life. Bizarre and disappointing.

I was not far from home and managed to make it back to the house without it failing again. This intermittent failure thing is annoying, but this time I really had not ridden the bike a long way and it did not seem to be hot. So maybe I am chasing another failure mode?

Anyway, I made some more inquiries online and the next suggestion was to look at the ignition switch. I had not thought about that since the bike always seemed to start up perfectly from a cold start. I looked up the instructions for how to remove the switch and clean the contacts. While cleaning the contacts, I happened to accidentally tug one of the wires and it broke off.  (Duh-I should have inspected all of the wires first since a frayed wire could explain a lot).  Apparently, that ground wire had been frayed down to a couple strands pulling all the juice. Didnt take much to break it off, and so even if it wasnt the problem-it was going to be a problem soon.

So I resoldered the wires and cleaned up all the contacts. At this point I cant say I am confident that the situation is behind me, but I can say that at least one future headache has been avoided. While I had the gas tank off I also checked every connection and ground wire I could find. In particular I focused on the main ground wire attached to the frame and made sure it was good and tight.

I'll take it for a ride next weekend and see if this helped. Fingers crossed.

It's all a Matter of Timing

I had used a sharpie to mark the old HES assembly and the housing before I removed it. However, I should have probably scribed a line to mark the edge of the housing or something since half of the reference mark was on the old assembly. Duh. So now I have a nice mark on the housing, but no precise marking on the new assembly. I hoped I might be able to eyeball it but it didn't work.

So I had to do a little trial and error. I moved the ring a few mm clockwise and counterclockwise until it seemed to provide a smooth idle and reliable high rpm performance. I did not have the fancy BMW test probe or any of the other tools recommended in the manual. But fortunately I tweaked and tweaked until I hit a sweet spot pretty close to my sharpie mark. Just a few mm on either side of the sharpie mark and the bike was awful, stalling and missing. Then, wow...the sweet smooth turbine sound of the k-bike returns.

I'm going to see if there are instructions for how to build the timing test probe. It can't be all that tough and I'm guessing BMW charges an arm and a leg for one. But for now it seems to be running fine and I may decide to go out an try a longer ride tomorrow after my wife and I have out Sunday morning round of golf.

KIds in the Hall Effect

Intermittent problems are the most annoying of all. When a bike won't start, or always pulls to the left or something you have this repeatable event that helps in the diagnosis. When the problem is intermittent you have to be thinking-will this be the ride where I get left stranded?

I had noticed that the problem seemed to occur only on hot days in stop & go traffic. Since the cooling fan and coolant temperature sensor had both been replaced, I was confident the engine wasn't overheating and that the ignition control unit was getting an accurate signal. So I'm really looking for something that gets flaky at higher temperatures. That tends to be electronic goodies. Maybe my ignition control unit is going bad.

I did some reading on the ignition control system and posted a question on a forum. The problem description led some of the more experienced wrenches online to the hall effect sensor. This is basically a timing switch that sends out a signal when a metallic element enters its path.  Apparently they crap out at high temperatures after a while, acting up like mine did , when they are in their death throes.

The diagnostic test for a intermittent failure of a hall effect sensor (HES) is to let the bike cool down, start it and see if it idles normal. Then you point a blow dryer at the T-shaped section in the front of the engine that houses the HES. If the HES cuts out when the blow dryer gets it up near 150-160 degrees F, then you have your culprit.  In my case, it went from the smooth idle to the chugging death spiral in minutes. I couldn't even get it to restart. After I let it cool 20 minutes it started right up again. We're onto something here!

Then I went to the Euro Motoelectrics site to see how much a new one cost. HOLY CRAP! They want $400 for a new one?  That would eat up my 20% budget pretty fast.  I scoured the forums for some options and found that I could get a working replacement on Ebay for $100, or I could get replacement sensors for about $40. So I decided to do both. I would have a direct replacement assembly that is plug and play, and I would have the components to rebuild my old one as a spare.

The new HES unit arrived in a few days and it was pretty easy to replace. Pop off the gas tank, remove the electrical connector, snip a couple zip ties and then remove some bolts from the T-shaped HES cover. I carefully marked the location of the base plate notches relative to the notch in the HES housing so I could get close to the original timing.

So I swapped out the unit, bolted the cover back on and it started right up again. Took it for a ride around the neighborhood and it felt odd. Throttle response was poor and inconsistent and the bike stalled at the top of the hill. I managed to restart it, ride it back home and started scratching my head again. Crap-tastic!

Wired

After the chugging, sputtering sluggish response I endured near the end of my prior ride I was a little concerned about the bike.  It had seemed like the bulletproof K may have something more than a flesh wound.

I pulled the plugs and checked them. Not bad but not great either.  A bit on the rich side for cylinders 3&4. So I thought maybe I was not getting good air flow. I replaced the air filter & fuel filter since I really wanted to make sure all the maintenance was current anyway.

While inspecting the spark plug wires I noticed that the wires were looking a bit ragged so I got a new set of silicone NGK wires and bought new plugs too. I remember someone once advised me to factor in 20% of the price of a new bike to fix all the hidden problems . So I was still well within 20% of the sale price while bringing all of the critical maintenance up to snuff. And I was well below the $1300 the dealer estimated to fix the bike.

While replacing the air filter ( a real knucklebuster of a task) I also noticed that there were a few air hoses that looked cracked.  I replaced them and tighted all of the lines to make sure was minimizing air inleakage.

So when I fired it back up everything seemed great again. Good smooth pulling power, no issues at idle or high speed and the herky jerky throttle response seemed  behind me. I had fresh fuel, with a little splash of Techron added, fresh filters, and all new hoses. What could go wrong now?

I went out for a short ride and all was good. Commuted to the office the following week without any issues and felt I had the problem licked. On Friday, on my ride home from the office I ran into more slow traffic and hot Atlanta weather.  As I started to slow down,  approaching an intersection,  the engine started sputtering again and became real sluggish. As I rolled on more throttle it started to die.  I started pulling off the road. Then it regained some life, and I pulled back into the lane and made it home. Rats. Another issue to resolve.

Fluidity

Before heading back out on the bike I figured I would just replace all the fluids. I drained the transmission and final drive oils and replaced them. Although my odometer  reads around 24,000 miles,  you can't really be sure with an old K-bike unless you have a well documented title and detailed maintenance logs with receipts. Most K-bikes have had their odometer replaced. But based on the color of the fluids and the condition of the engine internals I have seen so far, this bike has at least been well cared-for. And for a K-bike, mileage is less important than the quality of maintenance since the design is so robust.
There were no signs of prior fluid leaks, and at the same time no signs that the engine externals had been mechanically cleaned with brushes, walnut shell blasting or chemical cleansers.

After a 100 mile test ride on the highway it looked like everything was coming together. Smooth acceleration, lots of power and no issues while zipping along around 70-80 mph. Could it be this simple -that all I needed to do was replace the radiator fan and coolant sensor and suddenly I had a nearly new K-bike? All seemed great until I exited the highway, stopped at a light and the engine bogged down. I was barely able to limp thru the intersection and coughed and sputtered to the other side of the road where suddenly the engine regained power and I was able to make it the rest of the way home.

Oh well, more troubleshooting ahead.

Tackling the Cooling System

I didn't catch the fact that the radiator fan had siezed up and -shocker- the previous owner forgot to mention it. I am sure he knew and it explained his desire to take my offer. At any rate, I took off the gas tank, fairing and radiator and swapped out the fan unit. While I had the bike apart I did a calibration check on the thermostat and it worked fine. I cleaned up the fins and then I also replaced the coolant temp sensor. Even though it worked fine I thought it would be prudent to just replace a 26 yr old sensor for 40 bucks while I had it apart. The cost for labor would be 5 times that at a dealer.
I learned a difficult lesson when I refilled the coolant. I overtorqued the drain plug and stripped the soft brass plug. A new plug only cost a couple bucks but I had to wait till I could get to the dealer for the part.

The good news is that I put it all back together and the new fan started spinning like a top once the temp sensor called for it. Very satisfying but my problems were not over yet.

Dealer Diagnosis

After replacing the clutch cable I rode the bike to the dealer for an inspection. Mainly i just wanted to make sure i did not have some huge hidden liability. The dealer estimate for parts and labor was almost $1300. They pointed out that I needed a new radiator fan and a bunch of hoses and clamps. They were nice about it and said that they could understand why i would not want to put that much money into a 26 yr old motorcycle. I told the dealer i would repair it myself and they actually printed off the list of part numbers i needed.

Armed with their parts list i went online and ordered all the bits and pieces. I naively thought online would be cheaper and faster . Actually the online prices were the same as my dealer had estimated. It took 2 weeks to get the parts online and i could have had them next day at the dealer.

The radiator fan was another story. The dealer quoted me almost 400 bucks for the fan and motor assembly. I found a used one for 50 bucks on ebay and i also had the option of a new motor for only $85. I decided to go with the ebay unit. Had the new fan in under a week.

Taking Delivery

I met the previous owner and took the bike for a ride long enough to  run thru all the gears, weave thru some twisty roads and try the brakes, lights and horn. It seemed to accelerate and stop well and the first noticeable issue was that the clutch lever was hard to pull.  I checked underneath the bike and didn't see any leaking and all the fluids seemed to be at the right levels. I realized this was a 26 year old bike, and frankly figured I needed to factor in 20% of the purchase price to fix all the unknown or hidden issues. When I worked out a price that allowed me the leeway I needed I pulled the trigger.

I was able to ride the bike home, park it in my garage and scheduled a visit to my local BMW dealer to have them do a detailed post-purchase inspection. As luck would have it, while I was driving it to the dealer, I pulled in the clutch cable and it snapped. Perhaps if I had looked closer I would have seen that the clutch cable was frayed under the rubber boot. Anyway, the previous owner had pointed out a worn spot in the cable sheath and had also included a spare cable. However, he had purchased a spare throttle cable -not a clutch cable. So instead of making a quick roadside repair of the included cable, I had to get a ride to the dealer, buy the new cable and install it myself. Lesson #1 learned.

Why & How I acquired my 85 K100RS

The why is simple. In 1985 I was in my mid-20's and first saw the K100RS in person in the parking lot of an upscale restaurant. It drew a bigger crowd than the Porsches in the lot. This bike was radically different and uber-cool.

 For years I thought I'd buy a K100RS but there were all those other things to take care of like attending grad school, paying off tuition, buying a house etc. Plus I was living in a cooler climate where the riding season was pretty short. Eventually, I ended up moving to a much warmer part of the country but by then I had reached a point in my careeer where, well, owning a motorcycle might be seen as some sort of mid-life crisis.

Recently I was reliving those old days and how much I had wanted a K-bike  when I was younger. The funny thing is that I could now afford to walk into the BMW dealer and drop cash on any sexy new bike in the dealership, but my preference was to find an old K100.  In "Zen and the Art of Motorcycle Maintenance" the author reminds us that when we are working on a motorcycle we're really working on restoring ourselves.  Like so many insights in the book, that line stuck with me. I think I wanted to buy a K100 to restore something that I had lost in myself. Or maybe just to see how much I had changed since 1985. Either way, it became a compelling thought.

From time to time I would check Ebay or Craigslist for a BMW, but the listings never seemed right. It would be either a major project , or a restored bike, or a salvage title. Until one day I came across the right bike and I snagged it for slightly over trade in value. I could see it needed some work, but was driveable.

What follows is the genesis of this blog.

Welcome to BrickFlyer

Welcome. This blog is all about my efforts to resuscitate a 1985 BMW K100RS. From initial acquisition through restoration headaches through (hopefully) the eventual sport touring adventures with the restored bike I plan to document usefull lessons for others who find themself in a simliar situation.

The 1985 is the first model year that the K-Bike was introduced into the states. For years, BMW built their brand around the R-Bike, an opposed twin cyclinder bike that has been commonly referred to as the "boxer" configuration. The "boxer" nickname comes from the way a boxer would punch their gloves together before a fight, both hands coming into the center and then pulling back if that helps you visualize it.

Anyway, the FMY (first model year) 1985 K100 was a radical departure from the tried and true boxer. BMW decided to go from an opposed twin to an inline 4 cylinder and then chose to lay the engine on its side. (I'll avoid the temptation to describe it as "out of the boxer thinking" since that would be really cheezy and predictable.)  The design of the early K-bikes led to the new nickname "Flying Brick" in reference to the shape of the engine laid on its side, combned with the sheer power and acceleration, While litre-bikes in the 100HP range are not big thing today, it 1985 this was a huge leap forward.

When the K100 was released in the USA it garnered a lot of attention and numerous awards. Since its introduction, owners of the bike have reported squeezing over 200,000 miles from the engine, a remarkable comment on the quality of the engineering and the passion of the owners who ride them.

What follows will be something of a diary of my experience with this terrific machine. Enjoy