Dot Dot Dot, which Dot is right??

[KCinSB]

I guess its been 5 years ago, when the bike was still on the road, "we" did some brake bleeding. My K75 Buddy and I worked up a rig to pressure bleed the systems, and I recall it was a success after some fine tuning. I recall there was talk of the Dot4 at the time, and I think that's what we used. I still have Dot3 on the shelf in the garage, which I suspect should be simply discarded. I wanted to top of the Fwd reservoir, and now hear there is a Dot5 !!  Is that OK to use if I think the fluid in the bike is Dot4?
 What's with all the Dots for crying out loud..........     

[Laitch]

Use fresh DOT 4. DOT 5 is not compatible with DOT 4 or your moto's brake system. Your DOT 3 suppy is probably water-contaminated and should be appropriately discarded.

Here's a link to a page that contains a K1100 Riders Manual. It contains specs of your moto's various fluids and other useful information. Scroll down to find the link; click on it to download a copy to your computer. You'll likely be less confused, in some ways, from here on out. The page also contains a link to a BMW K1100 shop manual.

[Scott_]

+1 to what Laitch said.... NO to Dot5, NO to Dot3 in the bike.
If the container has been opened, and it's over 1 year old, toss it, even if it is compatible with your cars/trucks(which ever you have).
When I bought my R1100, the PO put Dot3 in the front and it and it messed up most everything, Master seals went out(caused a leak that stripped the paint), both front calipers wouldn't fully release.
Luckily I had the parts from my totaled K to replace them with. A good flush and refill with Dot4 and all is good again.....I've not been so bold as to test the ABS on the front, though it does work for the rear.

[The Mighty Gryphon]

Brake fluid is one of the least expensive fluids you need for maintaining a brick. 

Five bucks will buy enough to do a complete brake flush on a bike with ABS.  Keep the leftover stuff for topping up and toss it next year when you get a new bottle for the next flush.

[alabrew]

It is DOT, not Dot, actually should be D.O.T.#

DOT = Department of Transportation and the number relates to the standards of the fluid.