Potential Future 85' K100RT Owner With Some Questions

[Jackstand Johnny]

Hi everyone. I i troduced myself in the proper sub forum and have some specific questions Id like to ask about a 1985 K100RT Im going to look at and possibly purchase. It needs work that the seller made aware but He will be riding it 20-30 miles to meet me so it has potential. So far I was told for sure its problems are:

-Fork seals are bad, no sure if its pitting on fork tubes or jist old dry seals
-Rear brake doesnt work, owner doesnt know why
-1 of the bolts snapped off for the handlebar clamps
-Odometer stopped working at around 8.5k miles, owner doesnt know why but Ive heard this is a common problem

I think thats it. So heres my questions as I have never owned a BMW at all, let alone a BMW motorcycle:

-How common are the problems I listed with these bikes specifically?
-Do I need special BMW tools to work on this bike and if so, is it a LOT of tools? I read that you even need a specialty bmw tool just to replace the oil filter
-What should I look for without having to tear into the K100RT? He said Hell be riding it so I dont want to take anythig major apart or fiddle with something that could compromise His safety, especially since Hes crazy enough to ride it without a back brake and leaky fork seals
-I kept asking if Hed send me pictures since His listing saod he would. He kept dodging my requests. I think thats very odd considering Ill see it in person anyways, but sketchiness aside, does the 1985 K100RT have a disc rear brake?

Are there any things specific to this year and model to look for? He is asking $1000 but said He would give me a deal. He didnt specify how much of a deal, but does this seem like a good deal for a running driving K100RT? Also I shoupd mention that my plans for the bike would be to make it as light as possible, keep the weight as loe as possible and build it into a cafe/streetfighter platform. So heres a few more questions related to my build plans:

-What USD frot end is the easiest to swap onto this bike?
-Are there better, wider or lighter wheels that bolts up? Does it take custom ,achined parts?
-Is there a better swingarm for this bike? How concerned should I be that it uses the single rear shock suspension?
-Are there better rear shocks out there other than an Ohlins or other expensive racing suspension?
-Can I install a better rear brake from another bike? If so, which one?
-What are the most effective ways to reduce weight on this bike? How top heavy are these bikes?

MOST IMPORTANTLY, can I install an electric piston actuator on the shifter that pushes and pulls the shifter? This is what the Kliktronic push button shifter system uses and I need one to ride because I have a prosthetic left leg. If this BMW doesnt work the same way as a conventional motorcycles shifter then its a dealbreaker u fortunately. So this is paramount over everything else!


I think thats all igot, but please add anything you think is of any relevance. Ill continue researching these bikes for the basics like what oil to use, common problems etc. Thank you in advace for your help. I hope this bike is ok and I can get a deal on it. I think they are beautiful machines.

[Martin]

Forks seals is a easy fix if you have a bit of mechanical aptitude. Pitting if not too bad is repairable, look it up on the net. Superglue JB Weld are just a couple of methods. Forum members have posted methods. Try bleeding the brakes, flush out thoroughly with new fluid. Kits are available as are new master cylinders but no longer cheap, good second hand ones come up occasionally but need to be thoroughly checked.  Is it just the odometer that's not working, if so the odometer gears are made of cheese but are available. Broken bolts can be removed sometimes easy sometimes not so easy. Price everything before you go ahead. Go into the library and research. http://www.motobrick.com/index.php/topic,5787.msg37331.html#msg37331
Regards Martin.

[Laitch]

Welcome, Jackstand Johnny!

If you have any questions, be sure to ask them. The K100 shifts like any other 20–30-year old bike—nothing unusual there. Many people consider K-bikes top-heavy. The easiest way to fix this is to remove the fuel tank. Most of your small problems are common; the broken clamp bolt is unusual. Most of the other problems your bike will have will be common, too.

Until you think of some questions, read up on K-Bikes here, here and here.

[Jackstand Johnny]

WOW, Im impressed by the fast response. Thank you! I am definitely mechanically inclined. I work on motorycles all the time as well as my Subaru. I just didnt know if the BMW was particularly complicated when doing fork seals or other semi routine repairs. I have been reading up non stop on these bikes. Im sure Ill have more questions by tomorrow.