Im just here for the advice and sandwiches

[Swampyankee]

I'm a longtime airhead guy. Sold my last R75/6 a couple years ago. Now I'm looking for a new project and since I've always admired K100RSs, I started looking. I looked at a decent 85 model, asking $1600. 60k miles and the owner allegedly bought it with 6k on it in 87 and has ridden and maintained it ever since. A plus to have that kind of history.  I might be able to get it a hunnert or so cheaper since he's moving.
He's got the typical upgrades - koni shock, luftmeister exhaust, progressive springs. And it has some typical problems - non working gages, leaky fuel tank, spongy brakes, dead battery. But overall the bike seems in good shape gor the year and mileage.
I would hope to tinker with it over the winter and have a decent rideable "classic" brick in the spring.
So is this an ok investment? Not looking to sell at a profit  but it would nice to know that is has some value when done.

[frankenduck]

Just me but I wouldn't buy a K with a leaking tank unless I knew of a GOOD aluminum welder.  Ks that sit often leak at the tank seams of the lower corners so finding a good used one can be difficult unless you get lucky.  Also 85s have a different tank than 86+ which could make finding a good used tank even more challenging.

Ride a K75 before you buy a K100.  They're both great bikes but the K75, as a triple, has a much smoother engine. They have less power, 75 hp vs. 90 hp of a K100, but IMO are a better ride.  I wouldn't get a K75 for 2-up riding though.

JM02 (I have six K75s but only 1 K100 which tells you what my bias is.)

[Swampyankee]

Thanx for the caveat. I've patched leaky tanks in the past using Caswells. I though I could do the same with this one.

[frankenduck]

Thanx for the caveat. I've patched leaky tanks in the past using Caswells. I though I could do the same with this one.

Caswell tank epoxy or Caswell aluminum brazing rod?

[Swampyankee]

I actually do know a very good welder. I work in the tool and die industry so I have alot of technical resources. Which is why I didn't think the leaky tank was a deal breaker. But I also didn't know the 85 tank was unique so thanx for that.

[daveson]

That change, and some others, occurred during '85, so you might have the earlier or later model.

My brick, for example, born on 15th November 1985, has the later model tank.

[The Mighty Gryphon]

Some thoughts for what they may be worth.

It's said that the '85 K100 had hotter cams than the following years.  At 60,000 miles the engine is finally broken in and ready for another 200,000 or so. 

Besides the tank, the first couple years had some other unique design features that were upgraded in the following years, so they aren't interchangeable with later parts.  Off the top of my head, the seat attachments, the rear cowl to go with the seat, the rear brake disc was slotted and changed to solid, the engine output shaft went from 6 rivets to 12 rivets, and the drive shaft and final drive went from 16 splines to 20. 

Problem areas to be aware of are the inside of the fuel tank, drive splines, and brakes.  The vibration damper dissolves in the crap ethanol fuel and fills the tank with gooey black residue that coats and clogs the fuel pump and the level sensor.  Brake fluid crystallizes and absorbs water that corrodes the master cylinders, especially the rear.  Injectors often need cleaning after extended idleness.  There is a grub screw in the shift mechanism that loosens on some bikes and leads to a lot of slop in the shifter.  The drive cushions for the alternator can disintegrate causing a lot of noise.  The O-ring on the output shaft will harden over time and cause a slight leak between the engine and transmission, and there are some rubber bits that crack over time(the infamous Z-tube between the crankcase and the intake air plenum is one).

At $1600 for a bike with 60K on it, none of these things would be that hard to correct.  Many of us have dealt with them and lived to tell the tale.  The beauty of the classic K is that once you have corrected the results of the idleness, it will be a stone reliable ride that doesn't really require that much maintenance.

[Rcgreaves]

I actually do know a very good welder. I work in the tool and die industry so I have alot of technical resources. Which is why I didn't think the leaky tank was a deal breaker. But I also didn't know the 85 tank

A double walled case 75 tank presents significant welding challenges not easily corrected in my experience .  I personally would recommend a test ride on a four-cylinder to assess the handlebar vibration before you buy.  Some don’t care my hands simply go numb cheers.

Motobricker such as Frankenduck have been a huge huge resource and enhancement to my brick adventures.

[koapono]

greetings Swampyankee. I am a fellow RI'er though from "upstate" (Cumberland).
I owned an 85 RS for 36 years, just recently passed it on to a young fellow who I fear intends to make a horrid cafe-racer out of it.
My bike had 206,000 miles on it all but 400 of them with me in the saddle. Aside from wear and tear items I never experienced a major component break-down.
If it hasn't been done by current owner you will likely have to replace all the rubber bits, vent hoses, manifold gaskets that allow the engine to breath and vent. Make sure the cooling fan works, water/oil pump doesn't leak, no oil drip in weep hole under the engine bell-housing. All of these are easily fixed, the bike is surprisingly easy to work on one you've learned your way around it.
yes, there are items specific to the 85 none of them deal breakers.
Yes they are buzzy and heat shedding is a bother in warmer months but tucked into that machine at 80MPH feels akin to sitting atop a cruise missile. An older version mind you but a joy to pilot through twisties in New England and arrow straight slabs in MT, WY and the Dakotas!
It's cool to have a FYK (first year K).
I miss mine but riding position and garage space became factors for selling. It still ran as new.
Still lots of bits and bobs available on the web and a surprising inventory of new stuff available from folks like morton's.
Hell, even Razee's may have some stuff laying around!
g'luck and happy hunting.
 

[Swampyankee]

A double walled case 75 tank

What is meant by "double-walled tank"?

[Rcgreaves]

What is meant by "double-walled tank"?

My K 75 fuel tank is aluminum requiring TIG for a repair.  The construction has an inner vessel and an outer vessel an air gap air gap between them.  To weld the inner is a challenge to reach. 

[Swampyankee]

greetings Swampyankee. I am a fellow RI'er though from "upstate" (Cumberland).
I owned an 85 RS for 36 years, just recently passed it on to a young fellow who I fear intends to make a horrid cafe-racer out of it.
My bike had 206,000 miles on it all but 400 of them with me in the saddle. Aside from wear and tear items I never experienced a major component break-down.
If it hasn't been done by current owner you will likely have to replace all the rubber bits, vent hoses, manifold gaskets that allow the engine to breath and vent. Make sure the cooling fan works, water/oil pump doesn't leak, no oil drip in weep hole under the engine bell-housing. All of these are easily fixed, the bike is surprisingly easy to work on one you've learned your way around it.
yes, there are items specific to the 85 none of them deal breakers.
Yes they are buzzy and heat shedding is a bother in warmer months but tucked into that machine at 80MPH feels akin to sitting atop a cruise missile. An older version mind you but a joy to pilot through twisties in New England and arrow straight slabs in MT, WY and the Dakotas!
It's cool to have a FYK (first year K).
I miss mine but riding position and garage space became factors for selling. It still ran as new.
Still lots of bits and bobs available on the web and a surprising inventory of new stuff available from folks like morton's.
Hell, even Razee's may have some stuff laying around!
g'luck and happy hunting.

Good to hear from someone from the rolling hills of Cumberland. I'm there often, and pass by on 295 on the way to Attleboro every day.
I'm still mulling over the choice between the K100RS I looked at yesterday, and a 96 Triumph Trophy 1200 north of Bangor, Maine, which I would have to buy sight-unseen and have transported due to the distance and limited time.
On the one hand, the Triumph is 10 years newer and 30k miles less. On the other, I'm really intrigued by the K bike, and being a former Beemer owner, I feel a bit of kinship toward it. You mentioned riding position - I sold an R100RS for the same reason, but it was more about the narrow bars. The seller of the subject K100RS said the bars on his bike are wider - R90S bars possibly - and they don't seem as extreme as my R100RS. On the other hand, I'm not getting any younger and riding comfort me become an issue - the other reason for considering the more upright Trophy.

[Past-my-Prime]

A MAJOR selling point for my K75 RT was the very comfortable riding position. I like to sit up, have my elbows at a comfortable bend, and my wrists straight. I've done a number of 500 mile days in the saddle of mine, and love every minute of it.

I'm not as fast in the twisties as some others (but plenty fast enough to scare myself) and not as quick off the line (a new clutch has helped with that, however) and my top end is only about 120 MPH so if that's a deal breaker, so be it.

Not trying to talk you off the 100 RS, I've been tempted that direction as well but for me as I age, I'm more and more happy to stick with this.

[The Mighty Gryphon]

Another vote for the K75 platform.  Silky smooth and able to run at 75 mph for hours on end. 

I have done several Iron Butt runs including the Bun Burner 1500 miles in 24 hours on my K75RT.  Crossing Kansas with a couple other guys on 1200cc touring bikes I had no trouble keeping up with them, even setting the pace at 90+mph for a couple hours.  I burned a tank of gas at 100mph in Montana.  Cross country blasts from New York to Colorado or Idaho are pretty easy.  One day from the Mississippi to the Rockies is routine for my RT.

Yeah, it probably isn't as fast in the mountains as newer bikes, but it's pretty comfortable in crap weather, the price is definitely right, and it inspires the confidence to run solo through some pretty desolate landscapes. 

[frankenduck]

Another vote for the K75 platform.  Silky smooth and able to run at 75 mph for hours on end. 

I have done several Iron Butt runs including the Bun Burner 1500 miles in 24 hours on my K75RT.

I did my Bun Burner Gold on a K75RT too. 1,610 miles from San Diego to Beaumont, TX in less than 24 hours. Then I rode another 851 miles to Jacksonville Beach, FL. 2,461 miles in just over 36 hours. Pacific beach to Atlantic beach. And I didn't need to ride at hyperlegal speeds to do that. The only time I ever went more than ten over was crossing Louisiana, but everyone in the left lane was speeding so I figured that my chances of getting a ticket were somewhere between zero and none.

[The Mighty Gryphon]

I did my Bun Burner Gold on a K75RT too. 1,610 miles from San Diego to Beaumont, TX in less than 24 hours. Then I rode another 851 miles to Jacksonville Beach, FL. 2,461 miles in just over 36 hours. Pacific beach to Atlantic beach. And I didn't need to ride at hyperlegal speeds to do that. The only time I ever went more than ten over was crossing Louisiana, but everyone in the left lane was speeding so I figured that my chances of getting a ticket were somewhere between zero and none.

I did mine from Fort Collins, CO to Marilla, NY, 1550 miles in 23 hours and 20 minutes on my 69th birthday.  It was the last day of a two week 9,000 trip to the west coast.  It wasn't a pleasant ride, I hit a steady rain in North Platte, NE that followed me all the way to Davenport, IA. 

The worst part was a couple dozen single lane construction zones totaling 150 miles on I-80 across Nebraska and Iowa where I was barely able to to maintain a 45mph average speed.  Every time I was able to outrun the advancing weather I hit one of those damn construction zones.  The speed was too slow to get me any protection from the rain behind my fairing. 

I'm pretty sure I set a world record for calling other drivers Effing Motherf***ers in a 12 hour period that day.

[Swampyankee]

I was alllmmooost ready to pull the trigger on the Triumph Trophy, but buying sight-unseen is becoming a logistics nightmare, not to mention the risk. I believe the Trophy sitting position is probably more relaxed like an RT so I was favoring that.
However, the seller of the '85 K100RS is offering me the bike at a discount since he'd rather sell it where is rather than transport it to his new home. So the deal is a bit more appealing.

Things that the seller has told me is 1) the bike was originally bought in Germany, ridden there on holiday, and then brought back to CT where the owners subsequently started a MC dealership. Not sure if there are any differences - good or bad - between an '85 bike built for sale in DE vs one built for the US market. 2) the seller pointed out that the 1st owner tricked the bike out at the time with Koni shock, Luftmeister exhaust (is that loud?), Corbin lower solo saddle (lower is better for me), prog springs, and slightly wider 'bars (R90S bars?).

I don't anticipate going long distances with this bike. It would be more of a country road burner. Having a "real" K100RS has it's own appeal, and I'm willing to endure some vibrations - heck, I've owned plenty of vibrators on wheels.

Along with the great support I see from sites like this, I think the bike, as old as it is, maybe my choice. Let's see if I can make a deal....

[koapono]

I think the K1100LT doesn’t get the love it is due. Mine is a 94.
I loved my K100RS, but I am 71 years young and with the aches and pains associated with that age I couldn’t ride the RS for more than an hour or so. After a 100 miles it felt like I was sitting on a C130 jump seat!
I can get on the LT and ride all day!
Great weather protection, plenty of luggage/storage space, smooth and silky on the road (especially if you throw a set of radials on it) and nearly mechanically bullet-proof.
When I first acquired the bike (2010) it had 30K on it and was sitting idle and neglected.
Didn’t take much to get her running as new though I did fiddle with ABS System for quite some time. Decided not to spend more on ABS repair than I did for the bike so I removed all the ABS components, installed stainless steel brake lines and never looked back.
Now has 150K and has become my go-to bike.
It just suits me.

[Rcgreaves]

It never occurred to me that deleting the ABS brain was an option. I'm studing the ABS brick on my K11RS right now... Cheers.

As long as we are still having fun..its a good purchase.

[Swampyankee]

Looks like I have the bike for $1350.  Now I have to figure out how to get it home...

BTW, I just noticed the ad says it's an '86 not '85. Not sure where I even got that unless I got it mixed up with another K100RS I've been looking at. D'OH!

[The Mighty Gryphon]

It will fit on an 8 foot utility trailer.  Just go a little diagonal to lift the gate.


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[Swampyankee]

My "new" bike is about an hour away. I can borrow ramps and put it in the back of my trusty Ranger like so many others that have followed me home. A trailer would be nicer...

Anyone in RI or CT, USA want to help a brother out? LOL

[Chaos]

BTW, I just noticed the ad says it's an '86 not '85.

Prolly better off with the 86.  85's didn't have the fork brace and lot's of other bits unique to that year, thought they are know as "FYK" (finest year K) Hotter cams gave them a little more HP.

[Swampyankee]

Interesting. He has the brace but had removed it. I thought it was an aftermarket piece.

[Chaos]

There may have been some non braced 86's produced, the factory one has a 2 piece front fender with the brace in the middle.  The 85's had a one piece fender and there were aftermarket braces available.