Author Topic: K100 Scrambler Canada  (Read 7309 times)

Offline Grant

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K100 Scrambler Canada
« on: June 11, 2018, 11:03:05 PM »
A few weeks ago I bought a 1984 K100 with 32000 original km. I like this year as it is pre-ABS and has rear disk brakes. It had been stored for 2 years. I took it out for a couple of rides and noticed a some drops of oil coming from the rear weep hole. On the 3rd time out the drip turned into a puddle of fresh engine oil under the the center kick stand. I know now that I should stop riding and replace the rear main seal and o-ring before the clutch gets soaked in oil.

I will be converting the bike to a scrambler, so will be looking to this forum for some help and advice along the way. I have started by ordering all of the parts for the rear main seal job and will be checking everything along the way, splines, boots, bearings etc. It coughed up a bit of smoke on startup, but stooped after it warmed up for a few minutes, hope this is normal?

It looks to have been well maintained by a BMW dealership, lots of invoices came with it, almost $6,000 CDN when I added up the total. I have always maintained my bikes without the help of a mechanic so will be doing all of the work myself.

I have a small unimat lathe and today made up a clutch centering tool from a scrap of delrin plastic.  [ Invalid Attachment ]  

Here is a picture of the bike as purchased so you can see where I started on the build.  [ Invalid Attachment ]

I will do my best to keep everyone updated om my progress. lots of work to do yet.



  • Abbotsford BC Canada
  • 1984 K100 0005895

Offline Grant

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Re: K100 Scrambler Canada
« Reply #1 on: June 11, 2018, 11:43:53 PM »
Trying to post the pictures.
  • Abbotsford BC Canada
  • 1984 K100 0005895

Offline Grant

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Re: K100 Scrambler Canada
« Reply #2 on: June 11, 2018, 11:45:09 PM »
K100 1984
  • Abbotsford BC Canada
  • 1984 K100 0005895

Offline Laitch

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Re: K100 Scrambler Canada
« Reply #3 on: June 12, 2018, 12:07:19 AM »
It coughed up a bit of smoke on startup, but stooped after it warmed up for a few minutes, hope this is normal?
Hope?  :hehehe :laughing-on-ground: If you don't know that's normal, you have more reading to do, and there is a lot here. Make yourself at home.

Stored on the side stand, oil seeps past the rings into the combustion chamber then burns off when the engine is started. For less smoke on startup, put it on the center stand. Many of these bikes do that to one extent or another. Keeps away midges. At least one owner has written he tips the bike to the right before starting.

Enjoy your project. There are several scrambler threads in the Custom section here, so they should be of some help.

  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Grant

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Re: K100 Scrambler Canada
« Reply #4 on: June 12, 2018, 12:26:42 AM »
I can't see the sense in tilting it to the right when the oil has already entered the combustion chamber, but will keep this in mind and park it on the center stand. Why didn't BMW index the piston rings to the top of the cylinders with a simple stop on the rings? My son has a beemer car and it seems to leak oil from various O-rings and strange gasket points, seems like a normal thing for BMW?
  • Abbotsford BC Canada
  • 1984 K100 0005895

Offline Laitch

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Re: K100 Scrambler Canada
« Reply #5 on: June 12, 2018, 01:14:50 AM »
I can't see the sense in tilting it to the right when the oil has already entered the combustion chamber, but will keep this in mind and park it on the center stand. Why didn't BMW index the piston rings to the top of the cylinders with a simple stop on the rings?
Sense?  :hehehe :laughing-on-ground: Why didn't BMW . . . ? Why care? Many of these bikes have been documented working well beyond 100K miles, smoke or no smoke; that is, once they stay lit. :giggles 

O, the fun you'll have!
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Grant

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Re: K100 Scrambler Canada
« Reply #6 on: July 12, 2018, 07:20:47 PM »
Thought I would add an update. There was a terrible rattling / grinding sound coming from the top of the engine, I narrowed it down to a sound from the gas tank by putting my ear to it. It turns out that in the 1984 k100 BMW installed a fuel return check valve at the top left of the tank to prevent fuel from flowing out when the tank was removed. The valve was not installed on future models as it made too much noise. I found a reference to this after much research, not a common problem, the part does not even show up in fuel diagrams.

The fix was to remove the valve and take out a spring and ball bearing. For anyone with a similar problem: you can simply remove the valve without removing the gas tank, I removed the gas line, used a long socket, unscrewed the valve, pried the cover off of the valve and removed the spring and ball bearing. The o-ring that the bearing sealed against had moved up on the spring, the bearing was rattling around free in the bottom of the valve. I will look at putting in an in-line fuel valve so that the gas can be shut off when I remove the tank.
  • Abbotsford BC Canada
  • 1984 K100 0005895

Offline Grant

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Re: K100 Scrambler Canada
« Reply #7 on: July 12, 2018, 07:45:53 PM »
Sense?  :hehehe :laughing-on-ground: Why didn't BMW . . . ? Why care? Many of these bikes have been documented working well beyond 100K miles, smoke or no smoke; that is, once they stay lit. :giggles 

O, the fun you'll have!

So they last a long time? it is still a pain in the butt to have to put it on the center stand every time you park it to avoid the embarrassing clouds of blue smoke when you start it. I still rest with my claim of bad design. 40 years ago I had a 1972 Honda 350, when it started blowing blue I knew it was time to rebuild the engine, I rebuilt it 3 times and put over 300,000 miles on it.
  • Abbotsford BC Canada
  • 1984 K100 0005895

Offline Martin

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Re: K100 Scrambler Canada
« Reply #8 on: July 12, 2018, 08:14:20 PM »
There is one theory that you can reduce the smoking by tilting the bike to the right after shutting down. :dunno Personally it's only a problem, if you can call it a problem when left overnight on the side stand with mine. Early Bricks had floating rings in that they could rotate around the piston. The resulting smoke was supposed to be at it's worst when the ring gaps aligned. In an attempt to stop this the later Bricks had their rings pegged at intervals so they could not rotate.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Grant

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Re: K100 Scrambler Canada
« Reply #9 on: July 12, 2018, 08:20:32 PM »
The front brakes started pulsing, on and off every revolution of the tire. Very annoying when coming to a slow stop. I read several posts on the subject. I decided to try the lowest tech solution. I had my son sit on the back of the bike whilst it was on the center stand. 

I proceeded to turn the front tire while spraying liberal amounts of brake cleaner on the rotors and calipers. Tons of black crap came off on the floor. I wiped down the rotors with a rag and repeated the process several times. I then took the bike out on a back road and hit the brakes really hard for several stops. The end result was no more pulsing. perhaps something got stuck in the pads? Maybe something got on the rotors? Anyways I hope this may help others.
  • Abbotsford BC Canada
  • 1984 K100 0005895

Offline Grant

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Re: K100 Scrambler Canada
« Reply #10 on: July 12, 2018, 10:33:24 PM »
There is one theory that you can reduce the smoking by tilting the bike to the right after shutting down. :dunno Personally it's only a problem, if you can call it a problem when left overnight on the side stand with mine. Early Bricks had floating rings in that they could rotate around the piston. The resulting smoke was supposed to be at it's worst when the ring gaps aligned. In an attempt to stop this the later Bricks had their rings pegged at intervals so they could not rotate.
Regards Martin.

Mine will blow smoke after only 5 to 10 minutes sitting. When placed on the center stand there is no smoke at all. I am starting to like the bike even with all of the quirks. I thought I had some major problems with it, but they all got solved with some research and some wrenching. It seems the more you ride it the better it behaves. My bike is a 1984, many changes and fixes came thereafter, however I don't have to deal with ABS and emissions controls. 
  • Abbotsford BC Canada
  • 1984 K100 0005895

Offline Martin

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Re: K100 Scrambler Canada
« Reply #11 on: July 13, 2018, 12:56:51 AM »
Bricks do not like sitting and need to be ridden. You are sometimes better off buying one that has higher mileage but has been constantly ridden than one with lower mileage that has been sitting. However once the teething problems of getting it going again have been overcome, the more you ride it the better it becomes. Once running try running a couple of bottles of Techron through it.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Laitch

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Re: K100 Scrambler Canada
« Reply #12 on: July 13, 2018, 05:12:37 AM »
So they last a long time? I rebuilt it 3 times and put over 300,000 miles on it.
The idea I failed to convey, Grant, is that they last a long time usually without needing to be rebuilt 3 times. 300K? You'll find out. Anyway, like you're starting to realize, the more you ride it the better it will behave.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Arktasian

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Re: K100 Scrambler Canada
« Reply #13 on: July 13, 2018, 08:58:34 AM »
Hi Grant, nice bike. Not sure you've noted my "contentious" post on this same forum to do with a K75 project.
I've done a Siamese alteration to the stock left hand deploy side stand to allow a right hand tilt & hence oil conveyance away from combustion chambers. Some photos and dimensions listed for anyone likewise "inclined"  :hehehe. You having a lathe and an aversion to the smoke - felt you might be interested.
This bike was meant to be a "fun/ work through the rainy winter months" low stress project but I have to admit even with other busy life stuff going on keeps beckoning me to engage more significantly and set a completion target (some of the modifications as listed are rather "non-routine" and extreme as you can read).
I actually hail from Abbotsford as well - hence we may cross pathways at some point. I ride a Mocha brown 83 R100RT (turbo'ed, fuel injected, etc.) which being a sleeper escapes much notice from even staunch bmw enthusiasts.
Was your list of previous work courtesy Shails?
Good luck on your project,
Lorne
  • Abbotsford

Offline DJEwen

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Re: K100 Scrambler Canada
« Reply #14 on: July 13, 2018, 04:04:05 PM »
When I shut down I lean her to the right for 10 seconds before putting her on the side stand, she doesn’t smoke again at start up after doing this.
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline Grant

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Re: K100 Scrambler Canada
« Reply #15 on: July 13, 2018, 05:44:41 PM »
I will have to give this a try and let you know how it works, thanks for the great tip.
  • Abbotsford BC Canada
  • 1984 K100 0005895

Offline DJEwen

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Re: K100 Scrambler Canada
« Reply #16 on: July 13, 2018, 06:05:46 PM »
I will have to give this a try and let you know how it works, thanks for the great tip.

Don’t forget your Elephants between your seconds.
  • Scotland
  • 1985 K100 'Revive', 1987 K100 LT

Offline Laitch

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Re: K100 Scrambler Canada
« Reply #17 on: July 13, 2018, 06:34:02 PM »
Don’t forget your Elephants between your seconds.
Or Kumbayas.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Filmcamera

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Re: K100 Scrambler Canada
« Reply #18 on: July 13, 2018, 07:25:16 PM »
Hippopotamus surely??
  • San Jose, Costa Rica
  • 1991 K100RS 16v ABS1, 2018 Triumph Street Triple RS 765
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Offline Grant

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Re: K100 Scrambler Canada
« Reply #19 on: July 14, 2018, 10:37:37 AM »
Thanks Guys, its always nice to have choices, I will let you know which works best :hehehe

On another note the starter wasn't engaging until the second push of the button, but has now started working on the first push, more evidence that the bike needs to be exercised. The starter probably had some gunk built up that worked its way out with some use.

There is still a tiny bit of oil coming from the rear weep hole, enough to form a drop for every hour of riding or so, I will tackle the rear main seal and any other problems that need attention on my way to the engine when the insurance comes off this September. The clutch feels very strong, so I am not concerned at the moment.

I ordered some new brake pads as a precaution and will be taking the brakes apart to inspect them and properly clean them when the parts arrive.

I will take some time today to adjust the handle bars and controls. The clutch lever feels a bit low and the bars feel too far forward, The signal buttons feel too low, not sure if they can be moved up?
  • Abbotsford BC Canada
  • 1984 K100 0005895

Offline Laitch

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Re: K100 Scrambler Canada
« Reply #20 on: July 14, 2018, 12:14:42 PM »
I will take some time today to adjust the handle bars and controls. The clutch lever feels a bit low and the bars feel too far forward, The signal buttons feel too low, not sure if they can be moved up?
All switch blocks, levers and the handlebar can be rotated, the switch blocks have some small lateral adjustment along the bar, and sometimes the slightest of adjustments can make a substantial improvement in comfort.
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline Martin

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Re: K100 Scrambler Canada
« Reply #21 on: July 14, 2018, 05:34:34 PM »
+1 Adjust before you buy, then try spacers and barbacks before buying bars.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Grant

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Re: K100 Scrambler Canada
« Reply #22 on: July 17, 2018, 09:05:09 PM »
I tweaked the adjustments over the last few days. as suggested a minor adjustment can make a large improvement. I found that i liked the clutch and brakes a little lower, this also brings the turn signals up a bit nearer my thumbs. I moved the handle bars a little closer which also improved things. Thanks for all of the advice, my ride is much improved.
  • Abbotsford BC Canada
  • 1984 K100 0005895

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