K100RT parked for three years

[schrocketeer]

A friend is dropping off an 1986 K100RT that has been sitting for three years.
Other than drain the gas, change the oil, coolant, and brake fluid, check (i.e. replace) the tires, what else should I do to get it back running well?
This will be my first time working on a BMW. Lots of Japanese bike experience.

Current Bikes: 70 CT70, 95 VLX600, 91 XR250, 97 XR100
Past Bikes: 86 TRX250, 02 GZ250, 83 Z50R, 78 ATC90, 86 XR250, 79 XR500, 72 AT1, 75 YZ360, 78 DT400, 75 DT125, 73 Trail 70
Dad's bikes I rode in high school: 69 CL175K3 Scrambler, 71 R5-B (RD350 predecessor)

[Laitch]

Other than drain the gas, change the oil, coolant, and brake fluid, check (i.e. replace) the tires, what else should I do to get it back running well?

Welcome, schrockteer! When you get the bike, let's have a photo.

In the meantime, go to this link then read at links listed under the sections Operation and General Maintenance. Get one of the Workshop manuals on the site for your bike.

[johnny]

greetings...

id also replace the fork oil and transmission oil and final drive oil after i pulled it apart for full spline lube...

install new plugs and new battery... once started on fresh gas id run lotts of techron in the tank with no corn ethyl...

go getts you some yeeehaaaa...

j o

[kris]

I've got one of those...sat for 9 years! (I'm not bragging...wasn't mine at the time). I would check steering head bearings, front wheel bearings and final drive for noise or wiggle. I am in the process of sleuthing whatever is causing a bit of play at my rear wheel....I'm thinking it's the tapered roller bearing at this point. There was no discernible noise at all. Other than that, DeOxit for electrical connections, air filter, the rubber bits, maybe lube the throttle gear (at the grip). You will see most/ all of that in the link Laitch kindly directed you to.
These things are beasts. The quality of the parts is pretty outstanding. I'm pulling stuff apart after 31 years and it looks like new.
Don't forget the judicious use of heat and cold when persuading stubborn bolts or other parts. Lots of copper anti-seize on anything going back in.
Check Chris Harris' "how to" videos on youtube....great stuff. Keep the kids out of the room when watching. His language can get pretty colourful.
Best of luck. These machines are, like many great bikes, becoming rarer every day. I feel fortunate to own one!

[schrocketeer]

Sour gas siphoned out of the tank. New battery and battery tender installed. Plugs pulled to verify not seized. Trying whack job number one to free up the starter.

[schrocketeer]

Just after unloading, then after cleaning off the first layer of shed grime.

[The Mighty Gryphon]

That's going to be a sweet ride.

[schrocketeer]

If the starter-reverse-whack job doesn't work, where would you turn next, not-starting wise?
There's a new battery in it. Dash lights up (see attachment), brake lights come on from front or rear.
When I push the start button there is a hum/buzz that comes from the starter area.
I've pulled the spark plugs, and can move the pistons, by turning the rear wheel with my hands, while it is in third gear, and on the centerstand.

[Martin]

The starter will benefit from a clean, it takes about an hour. I did a reverse spin on mine and it partially worked but it didn't fully fix the problem. So I pulled the starter and I was glad I did, the commutator was filthy, but the brushes were fine. When refitting the starter it is advisable to smear the surfaces where it goes into the housing with Copper Kote. A mate had to slide hammer his out due to corrosion on the mating surfaces. Before and after refitting it try connecting it to a 12v battery just to see whether it is a problem.
Regards Martin.

[Skunky]

Looks like a great buy some body work to do. Whats the Mileage My dim eyes are seeing 40k?. Must feel heavy after all those dirt bikes.

[Skunky]

The Starters not difficult to remove. Why not take it out and spin it off the battery. You can also give it a harder Whack  :beatdeadhorse:

[The Mighty Gryphon]

It is possible that the starter motor may not be engaging the sprag clutch to spin the engine.  This is not an uncommon problem with early bricks, especially the K100.

Pushing the bike backwards in 5th and popping the clutch will often free things up.  Look up "back spin" for more information.  There are other fixes that you can read about by searching on sprag clutch.

That Mystic Red paint looks nice.  Those heavy fairing panels are easy to repair.

[Laitch]

When I push the start button there is a hum/buzz that comes from the starter area.

Determine if the noise is coming from the relay box under the tank and if it is, determine which relay is the buzzer. New batteries can be faulty.

If you haven't already, check battery terminal clamps for tightness and the transmission ground strap also.