K75 Oil pan gasket? and 60/40 coolant recomended?

I"m overhauling a 91 k75s and had a couple of questions. The book seems to indicate there is no gasket for the oil pan. Is that correct? Just Sealant? If so, I gather I will use the black tube stuff from Autozone unless someone recommends something else. The bike has sat and I thought I should remove the pan, clean the oil intake screen, and maybe be able to clean off the inside of the sight glass while I am at it. Does that all sound reasonable?

Second, the Clymer manual recommends a coolant mix of 60 water/40 antifreeze for better cooling. I usually use a 50/50 mix for everything but I"ll mix up a special batch (with distilled water, also recommended) if everyone agrees that the 60/40 mix cools better.

Last,(for the time being), what is the red hazard light that sits above the neutral light on the dash, for? I don't have a handbook for the bike yet. Thanks.

That is correct - no "true" gasket. I would check out Chris Harris's recommendations for the oil pan gasket material. Three bond - 1194 (his recommendation, found on Amazon) is what I've used on two K75's recently with no problem. The biggest thing is to make sure that both sealing surfaces are 100% clean before you start putting it back together. Any small flex of junk, will allow it to leak.

I go 50/50 for my coolant/distilled water (yay MN winters!). I would also recommend you either use the BMW brand or some people go with Preston Extended life. Anything else will eat away at the aluminum engine. (BMW is more expensive, but I don't have to worry). I feel okay remembering that the K75 has the same sized radiator as the K100 - plus the 3rd degree burns on my legs in the summer remind me that it seems to cool okay

The triangle above the neutral is your "Bulb Monitoring Unit" - it make sure that both the front and rear brake switches activate the brake light, and then that the light actually fires on. It will stay lit until you press both brakes (then it may flash with the ABS light if you have ABS until you move ~10ft or so), then it should go out. If yours is constantly lit, then either your rear bulb is blown, the switches are broken/misaligned, or someone replaced your bulb with an LED that doesn't draw enough current.

Good luck with your rebuild!! They are truly wonderful bikes!

jconway607 said:

...if everyone agrees that the 60/40 mix cools better.

Click to expand...

Like which direction gravity acts, it doesn't matter whether everyone (or anyone) agrees. It is a thermodynamic fact that 60W/40AF cools better than 50W/50AF. Another fact is that 100W/0AF cools even better than that. The question is what level of anti-freeze do you need for proper freeze, boil-over, and corrosion protection? Your ideal mix will be the lowest anti-freeze ratio that accomplishes these three objectives. 60W/40AF would give you freeze protection to -10F and a boiling point of 220F. 50W/50AF would give you -35F and 225F. I wouldn't worry about the boiling point, as most of that protection comes from system pressure. As far as corrosion protection, it depends on how often you change your antifreeze and which one you use. If you use long-life nitrite free antifreeze and change it every couple of years, then 60W/40AF is fine for corrosion control.