Bought 1987 k75s.
It has 136 thousand km on it. What issues might I expect? The p.o. Took it across Canada last year.

How often does somebody named lucki actually goof?  

Regarding the p.o.'s trip across Canada:
Was it ridden across Canada, or taken on a trailer? I’ve met a few sellers who might claim something like that and let the listeners draw their own conclusions.  

A Brick with 136K kilometers is barely middle-aged; having that many kilometers at that age is a good thing. Neglect disables Bricks; however, much hinges on how it was ridden and maintained. Read over Ted Verrill’s list. Some entries about oil types or air filters are debatable—like everything else these days—but it is a valid guide for new owners. Useful information regarding inspection or repair can be found in the Tech Page accessible in the K100-forum’s Portal. Without a verifiable or convincing history of maintenance for a reference, priorities for inspection may differ among Brick owners.

I think that works out to about 85,000 miles.  Since my K75 hit that number I have put on another 15,000 miles doing two trips, one around Lakes Huron and Superior and a second across Manitoba, Saskatchewan, and Alberta into the U.S. to the West coast down to Death Valley and then across Arizona and New Mexico on Rte 66. If not for the Covid lockdown of the border I would have taken it to Alaska in 2020.

Bottom line is that 136,000km is nothing to a properly maintained K bike.  Correct any problems you find and go for a ride, a long one.  That's what these bikes are made for.

Thanks for the words of encouragement. Always wanted another bmw, had a very nice 1983 r100rt that I should have kept! Probably my last bike the k75. Turning 80 this year. Current ride is a nice Yamaha xj650 seca. Can you have too many bikes?

lucki wrote:Can you have too many bikes?

Damn stupid question that is (mumble mumble mumble).

Dai
Thanks for the warm welcome to the site.

lucki wrote:Can you have too many bikes?

Can you explain I don't understand

Q: How many bikes is enough?

A: One more.

Only problem is keeping the batteries charged and draining the fuel, I have too many but still buy more. One day it must stop.

20 is enough for me.
It ruins me in batteries...

Nice to see I am not alone in having more than one bike.
Update
Picked up the k75s yesterday. Almost walked on the deal. Bike was worse than p.o. Let on.
Needs tires, battery, windshield, worse of all, tank leaks. Made a deal for a lot less money. I don't think the bike wlll see the road this year. Tank coming off this morning. Leak is at lowest point on the shift side. Checked out posts for repair, any thoughts?
Good news is bike turns over when battery jumped! He asked 1800 bought for 1000.

Sounds like your tank is leaking in the traditional spot.  While welding is the best repair, many have had good luck with epoxy like JB Weld. 

If the bike is indeed really bad, the first thing I would do is is remove the tank, seat and the fairing and give it a good cleaning with S100. I do that even when I get a bike in good shape.

If you haven't used it, S100 is an amazing cleaner that cleans down to the paint without damaging any of the finish.  Used and approved by thousands of obsessive compulsive Hardley Dangerous motorcycle polishers.  A clean bike is much, much more fun to work on. 

Then I would put a bottle of S100 near a spot where I can clean parts as I remove them.  That way, I am detailing as I go along.  The parts will then be degreased enough for a preliminary paint prep when you get to that point.

With the bike clean, you can start working on making it run.  Lots of help here for that.

With a running engine you can start doing a tear down inspection starting with the wheels, suspension and drive train.  Spline lubes, wheel and steering bearings, forks and rear shock.  Whatever you run into, there are several here who have seen it as well.  Should be a fun project.

Point thanks for this.
Just got the tank off, many pin holes. Got it prepared. Try to post picture, not sure how.

jbt wrote:20 is enough for me.
It ruins me in batteries...

Just keep taking them out in turn. Gets over the problem.

Update
Cleaned tank holes, p.o. Had been in and plugged two leaks in the past. Used premex because label said for aluminium and resists auto fluids. Cure time 24 hrs. Cleaning up ground connections. Pulled plugs, look good, gave each cylinder a shot of oil to increase compression, been sitting a while. Tank goes back on tomorrow, try to light it up!

What is premex?

Point-Seven-five wrote:What is premex?

Aztec or Mayan.

Sorry to mislead. It is permatex cold weld epoxy. After cleaning and sanding area I used an eighth in twist drill to clean the hole walls.I applied two coats the first one was thick and I tried to get it deep into the holes to hopefully form a bit of a plug inside the tank. The second coat done when the first one tackie. Permatex said to let cure 24 hrs. Tank goes on tomorrow, will let you know if it leaks. Tried to send pictures but still can't figure it out.

Another question. When doing the drive shaft spline lube I understand how to do it but if you pull the drive shaft out without taking off the swing arm how can you get it back in? Must be a trick to it.

When doing the drive shaft spline  lube I understand how to do it but if you pull the drive shaft out without taking off the swing arm how can you get it back in? Must be a trick to it.

If you're able to lever the driveshaft out of the swing arm, to install it you shove it back in there, rotate it until the u-joint splines engage with the transmission output shaft splines, then knock it firmly with dead blow mallet or hammer, if necessary, until the snap ring within the u-joint engages with the groove in the transmission output shaft. Success is indicated by the inability to remove the driveshaft without levering force being used again. Sometimes a u-joint weld will be too thick to allow the driveshaft to pass through the swing arm's forward opening; in those cases the swing arm gets removed first.

Wear occurs at the rear end of the driveshaft. The wear is caused by the constant sliding of the driveshaft's splines against the rear drive's splines responding to the wheel's rebound during travel. Wear doesn't seem to be a problem at the other end because engagement by means of the circlip limits sliding, so just thoroughly clean then lube the driveshaft and rear drive splines while the driveshaft is attached to the output shaft.

Frequent sliding engagement and lack of appropriate lubrication is also what can destroy clutch hub splines and the transmission input shaft splines. If you don't know when they were lubed, eventually you'll need to inspect them. Difficulty shifting when the clutch is accurately adjusted is often the first sign of lack of lubrication there.

What he said and why it isn't a bad practice to lube the rear drive shaft splines whenever you get a new rear tire.

False neutrals when downshifting are a typical symptom of clutch splines needing lubrication.

From the overall condition of this bike I don't want to go to a lot of expense if spline is shot. First I would like to get it running to see what I got then remove the final drive to check spline. As I dig deeper into this bike I am afraid the p.o. gilded the llilley a bit.

I looked all over this site for how to send pictures, can't seem to figure it out. Tips?

lucki wrote:As I dig deeper into this bike I am afraid the p.o. gilded the llilley a bit.
I looked all over this site for how to send pictures, can't seem to figure it out. Tips?

It could be that the p.o. gilded a cactus instead but it's a trifle too early to determine that.

There are a couple of step-by-step explanations of how to post photos using this forum's software. I sent you a personal message with one of them a couple of days ago. I guess it escaped into the cosmos. Regardless, here's the short one and here's the wordy one.

lucki wrote:From the overall condition of this bike I don't want to go to a lot of expense if spline is shot. First I would like to get it running to see what I got then remove the final drive to check spline. As I dig deeper into this bike I am afraid the p.o. gilded the llilley a bit.

I looked all over this site for how to send pictures, can't seem to figure it out. Tips?

Shot splines are not end of world though. 

As you say, get it running first. Plenty of help/advice etc in the forum.

Many thanks, not so bad.

It looks like you have enough wrenches so the rest should be a piece of cake, if your hands don't get impaled by cactus spines.

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Lots of tools to farm!
Any idea if this aftermarket and very old shock is worth using?

How many miles?  Properly maintained splines will last a long time.  My K75RT has 100k and the splines still look new.

Your tank has the typical corrosion that comes from water settling in the low spots in the tank.  Your fix should take care of it.

Clutch splines can be done without fully removing the transmission by sliding the transmission back on a pair of long bolts that are screwed into two of the mounting bolt holes.  Then a long parts cleaning brush with a tiny bit of lube can get in there from the side.  Eventually you might want to pull the transmission to replace the clutch o-ring which, if it hasn't been replaced, may begin leaking a small amount of oil.

I can't identify your shock, but it looks like it might have a damping adjustment on the reservoir.  My experience is that most aftermarket shocks of the era were rebuildable by replacing the seal and doing a nitrogen recharge.  As long as the shaft isn't bent, I would guess that it can be made to be usable.  I suspect that you aren't going to be dragging the pegs on this bike so that shock should be fine.

Their is 122000km showing. Got the bike to fiddle with on rainy days but can't seem to stay away from it. Watched a lot of Chris harris videos. Should try to start it soon, don't want to rush the epoxy job on the tank. Also as I take things apart a lot of odd nuts and bolts on the fiberglass parts.

The drive shaft came off with the final drive. Spline at the final drive was stuck in with hardened grease. Cleaned them up and when dry you get about a sixteenth of an inch play when you put the drive shaft on the final drive and twist the shaft. Sound not bad? Doubt this thing ever off.

You need to show us a picture like this of the splines. Here's what worn splines look like.

Greased up and back together. No way did it look this bad! Thanks for the photo, makes me feel better.

This is what you would like to see.  Nice big flat areas at the top of the splines.  These photos were take at about 92,000 miles.

Mine are thin for sure but they did have some flatness to the tops.. In a good year I might put on 2000 miles. At my stage of the game I don't plan too far ahead.
I really appreciate the help given!

It's Alive!

Put tank back on, no leaks so far. Cranked over a bit but started and ran smooth, smoked but cleared.
A few question:
Must the temp warning light come on before th fan?
Any way to test fan in bike?
Used a remote camera to look in tank, quite clean, gas leaked
out holes.
I could read numbers on filter, 20 03 15, what year 20 or 15?
Any further suggestions?

Great that it's running now!  That smoke was probably the oil you put in the cylinders, at least the mosquitoes won't be a problem for the rest of the day.

I'm going to guess March 20, 2015 on the filter in preparation for the riding season.  In an old bike it's money well spent replacing it.

You can test the fan by letting the engine idle for about 5 minutes, that should be enough to get it to cycle.  Before you do that, see if you can easily spin the blades.  Common problems with the fan are seized bearings and melted brush holders.  The blades have also been known to come loose on the shaft and slide forward to hit the radiator causing leaks.

When letting the engine idle I put a fan on the exhaust headers to get some airflow over them.  They want to get pretty hot if you don't.

Many owners will install a manual fan override switch so they can run the fan continuously when stuck in traffic on a hot day.

The fan comes on at 103C, the temp warning light comes on at 111C. The temp warning light does not come on before starting because the coolant is at ambient temperature.

Fan testing:

1 - If you can easily spin the fan blade by hand that is usually a good indicator that the fan is working.

2 - You can let the bike sit and idle for a LONG time and the fan should eventually come on before the temp warning light does. I wouldn't recommend that because it will foul the plugs a little on a K75. It wouldn't be the end of the world though.

3 - Find the fan connector under the left side of the tank. It's a black rectangular connector with violet/yellow and brown wires. If you jump 12V to violet/yellow and ground to brown then the fan should spin up.

If you're concerned about the fuel filter then just replace it with a 3032 fuel filter from NAPA.

lucki wrote:Any further suggestions?

Check the crankcase breather hose.
http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/ccb/ccb.htm

The fan now turns easy however it was very hard to turn by hand but I worked it and is now free. Damage might have been done will isolate fan and test.
ran the bike at 1500rpm for ten minutes fan did not come on.
Breather hose seems okay, tightened clamps.
Will replace fuel filter, Napa number great.

Ran bike for 10 min, used a hand held temp sensor upper rad area got to 107c no fan and the fluid in the overflow tank cold.
Also bike started well burned clean then as it got about 100c started to smoke blue oil.
Thoughs?

lucki wrote:ran the bike at 1500rpm for ten minutes fan did not come on.

Run it for 20 minutes. I'll bet the fan—if it works—will run for a minute then shut off before 20 minutes. Never mind the smoke right now if there is sufficient oil showing in the sight glass.

I think that rather than risk damaging the engine by running for an extended time with inadequate cooling I would remove the tank and apply 12 volts to the fan connector as the duck advised. 

Melted brush holders will allow the fan to spin while not making the motor run.  One of my bikes had this problem and required replacing the fan.  If you do need to replace the fan, beyond the work to get to it, the job is not too difficult and there is an excellent aftermarket replacement that is a lot lower in price than the fragile OEM fan.

I will take the tank off and check the fan. Not today spraying wheat.

Hi,

to this forum!


Bernie

Thanks Bernie
The kind response by others on the forum saved me a lot of work! The p.o. Of this bike was going to chop it somehow, sort of saved the old girl.

Fan works! Did not think it would. Fan was stuck a few days ago, soaked fan shaft near blades and worked it free it became easier and spun quite free before.I put power to it.
I will put a switch in.

Is their a temp senser to active the fan, if so where is it and how to test?
I would like to have both the auto on off and a switch. How did you guys wire this?

I don't have the wiring diagram, but I think there is a fan relay in the relay box.  If you put a switched bypass across the contacts, you can turn on the fan with the switch.

On my K75S I got a piece of aluminum about 1" wide and 3" long.  I put a hole for a toggle switch in one end and a hole to put it under the top fork pinch bolt on the left side.  Bend the aluminum to get the switch in a convenient place.

I Polack engineered the connections to the relay by pulling the relay out of it's socket and sticking the stripped end of the wires in the sockets and putting the relay back in.  Strip about 1/4" of the insulation off the end of the wire and twist the strands together.  Make sure all the strands go in the socket.  You don't want any loose ends causing short circuits.