New member...rehabbing a 1985 K100 Basic

[rawhites]

Hello! This is the bike I rode as a teenager, but it's been sitting in my dad's garage for 30 years. As a passion project, I'm trying to bring it back to life. Good with my hands and some mechanical experience, but this is my first bike rehab.

My biggest initial questions
- emptying gas tank....from what I read on other threads (about a K75) seems like a delicate operation. Any direction is appreciated!
- checking all hoses for decay...is there a test besides just eyeballing for cracks?
- replacing the battery...battery sites seem to list an 85 k100 RS (not basic) battery specifically....I assume these are interchangeable?
- besides the rear drive splines, what else should I clean/check/lubricate?
- checking chain health....I assume I can just clean & lube the old one
- best parts site?

Thanks in advance for answer and advice to any of these!!

 

[AntonLargiader]

Biggest issue is usually the fuel tank and what's inside it. The tanks corrode, especially at the left and right low points (especially the left if it's been on the sidestand). If the tank was drained before it was parked, great. If you see sticky residue on the outside of the tank at the low spots, it has corroded through. It's repairable.

Normally everything inside the tank is junk after that much time, but again it depends on circumstances. Everything being the pump, pump dampers (the rubber bits that hold the pump), the hoses, and the fuel float assembly.

You may need to soak, free up, replace, whatever, the injectors if they are stuck. The regulator is probably OK; just replace the fuel hoses. You can access the hose connections at the regulator by pulling out the airbox.

Once the fuel system is sorted out, the historic trouble spots are the rear crank O-ring and the oil/water pump. They're not unreliable; they just need to be renewed every decade or two. The pump can be rebuilt. Yeah; lube the rear drive splines and the clutch splines (you will be looking at both of these when you do the crank O-ring anyway).

Engine stuff is pretty bulletproof. Same for the transmission other than the possibility of a loose shift lever; if you feel any slop in the shift lever then deal with that while the transmission is out. Steering head bearings may need to be replaced (after 30 years, the grease can be so hard it's not worth cleaning them).

If the rear shock feels good, it probably will still die once you start riding the bike. . Unless it has already been replaced.

 

[skibum69]

Welcome from Newfoundland. It should be easy to find a replacement battery. Google is your friend.

 

[rawhites]

Biggest issue is usually the fuel tank and what's inside it. The tanks corrode, especially at the left and right low points (especially the left if it's been on the sidestand). If the tank was drained before it was parked, great. If you see sticky residue on the outside of the tank at the low spots, it has corroded through. It's repairable.

Normally everything inside the tank is junk after that much time, but again it depends on circumstances. Everything being the pump, pump dampers (the rubber bits that hold the pump), the hoses, and the fuel float assembly.

You may need to soak, free up, replace, whatever, the injectors if they are stuck. The regulator is probably OK; just replace the fuel hoses. You can access the hose connections at the regulator by pulling out the airbox.

Once the fuel system is sorted out, the historic trouble spots are the rear crank O-ring and the oil/water pump. They're not unreliable; they just need to be renewed every decade or two. The pump can be rebuilt. Yeah; lube the rear drive splines and the clutch splines (you will be looking at both of these when you do the crank O-ring anyway).

Engine stuff is pretty bulletproof. Same for the transmission other than the possibility of a loose shift lever; if you feel any slop in the shift lever then deal with that while the transmission is out. Steering head bearings may need to be replaced (after 30 years, the grease can be so hard it's not worth cleaning them).

If the rear shock feels good, it probably will still die once you start riding the bike. . Unless it has already been replaced.

Thanks, Anton!