'95 K 75S Fork oil

[95SKarsten]

Finally finished chasing electric gremlin this afternoon and was able to start the final chapter of my full service to my new to me '95 K 75S. Changing fork oil. I stared by removing the entire top cap because the filler allen head fill screw is permanently married to the cap. compressed cap, removed lock ring and started to drain right leg first, misjudged the force with which the fluid came out,was not able to capture old oil to measure quantities. Fluid looked clean with reddish tint. Proceeded to left and adjusted my method of capturing fluid. This side looked all grayish, nasty looking stuff. Let both sides drain for about 20 minutes, new washers and tightened the drain screw just  snug.  the amount out of the left fork leg was only about 310 cc. Refill is supposed to be 410 per leg. Should I go back with only 310 or go the recommended 410 ? worried that maybe some old oil is in the very bottom of fork and I don't want to overfill and blow seals out .

[Martin]

You might have to flush it out a few times in order to get it clean, change the fluid ( use ATF fluid while you are flushing as it is cheaper once it is clean revert to fork oil)  ride it for a couple of days and change it, do this until it's clean, the alternative is to disassemble and clean. You can vary the fork oil levels by adding more fluid to firm up as less fluid to soften up. I wouldn't vary it by more than 60 cc, others may contribute as to what they have varied it by. While you have the cap off try to remove the allen filler screw, I made up a spanner that will fit into the fork to hold it while I remove the screw. put a smear of Koppercote when fitting it. Spanner was made out of a ring OE spanner I cut the OE head off allowing enough room for it to fit inside the fork. I then brazed the ring on the cut off portion back to the head of the OE spanner.
Regards Martin.

[Laitch]

Should I go back with only 310 or go the recommended 410 .

The 1995 models Showa forks. Showa forks hold 410 to refill, 420 to replace.

[95SKarsten]

ok, thanks, I will flush it with ATF. Can I reuse the washers on the drain screw? I had ordered a new set and installed them, if I flush the fork legs I will have to re use them at least once and perhaps order a new set for when I go back with fork oil. Gonna be interesting to see if it rides better with proper amount of oil in the forks.

[The Mighty Gryphon]

No problem reusing the washers, I would just be very careful about how much torque I put on the screw.   There are numerous posts here and at other forums regarding how easy it is to strip the threads in the fork leg.  My feeling is that the safe torque on the drain plug is not enough to seriously distort the washer. 

[Martin]

As regard to the washers a few years ago I bought a kit of various copper washers for under $20.00 AU. I have bought heaps of these assorted kits, fuses, springs, nuts, bolts, electrical connectors, clips, "O" rings, heat shrink and they pay for themselves in a short time. They turn up at Saturday and Sunday markets.
Regards Martin.

[95SKarsten]

see how well my mind has been trained? I am only thinking "BMW Dealer", not a good one close by. My last order of overpriced washers took 10 days to get here. Harbor Freight here we come.

[Martin]

Sigh I wish we had a Harbour Freight, but alas we have to beg, borrow, steal, make, adapt or get parts from the US or UK. Otherwise we have to sacrifice our extremities and go local. :musicboohoo:

[The Mighty Gryphon]

Regarding fork oil, back in the day we used ATF in the Honda forks and shocks on our racing bikes.  Cheap and it didn't lose it's viscosity when it got hot(I can recall riding on railroad tracks where the shock got so hot it could burn your hand and still not lose damping).

Is there any reason not to use it in our forks today?   It worked great in the past, why not now?

[95SKarsten]

followed the advice to flush the fork wit ATF, took it for a 40 mile ride and changed the fluid to Honda SS 8W10. Just having the correct amount of ATF in the fork made all the difference in the world. I think I am going to like this old Bike.I noticed on my short ride that the bike throws off a lot of heat at the legs, is that normal? I have been reading a bit about folks having issues with the radiator fan. Is there an easy way to check proper operation of the fan? None of my R-Bikes ever generated this much heat.

[Martin]

Remove the snorkel, and stick your finger in or a stick or any long object and see if they rotate freely. They do not like inaction, OEM fans tend to seize if not run occasionally. A lot of owners substitute Spal fans which require a bit of modification. A good modification is to add an override fan switch which allows you to run the fan in traffic or as a test.
Regards Martin.

[95SKarsten]

blades are rotating freely, I suppose the heat generated is normal. Just a lot hotter then those old "Airheads". On to the next mission, installing aux/fog lights and we will be done. Time to ride

[Laitch]

Just a lot hotter then those old "Airheads".

That's from the radiator radiating.

[Elipten]

It is not called a toaster for nothing!  Best driven in cold climates!


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[Martin]

Due to my brick being black and living in Queensland which can get extremely hot. I have just fitted reflective double sided foam insulation to try and stop vaporization in hot weather in traffic. I decided to try it out on a hot day in traffic, it worked to a point, it still vaporized occasionally. But that was with a low fuel level approximately 7 Lt, on filling the tank vaporization ceased. I may look at insulating the lines.
Regards Martin.