Just spent HOURS refitting the radiator (1990 K100LT ex-police) All was relatively straight forward, EXCEPT the bloody rubber dam thing that fits on top of the radiator, between the top of the radiator and underneath the headstock.. What's its purpose? Is it critical to have it in place? Any ideas out there as to a good technique refitting the thing?

Aaaaagh!! Rickmeister.

one of the delights of playing with bmw stuff rick ....enjoy

It is really needed as it makes sure the air is pushed through the radiator and doesn't flow over the top and take the cooling effect with it.
As to how you get it in and make it stay there I can't help as I have not had any problems that I recall. I haven't done one on a K100LT for some time and I cant remember just how it went in. I seem to remember that I just put it in and poked a few bits through with the appropiate screwdriver.

As an idea you may want to place a piece of tape on the upper side of the radiator gap and apply silastic to one or both sides of the rubber insert. Easier said than done.

Or perhaps some double side tape to hold it in place. Again easier said than done.

You could also attach the seal to a thin piece of aluminium so it sits on top of the radiator and shroud and secure it there.

Thanks for reminding me that my RT has the same problem. Just some ideas of the top of my head about how to go about it. I think the gap is about 10mm.

Finished up strapping the rubber dam on with long cable ties, and removing the cable ties after installation. Haven't replaced the fairing yet...time will tell when it comes to fitting the radiator cowling.

Anyway...filled the system up with brand new coolant. The book says to start the bike and idle it until the thermostat opens, then let it sit and top it up. Easier said than done! The fuel tank (needed to start the machine) covers the radiator cap. The bike's in a million pieces...






Connected the battery, made sure that nothing was shorting out, ignition on...hit the starter...Zilch. Bugger. Connected the instrument pod, ignition on, hit the starter and 'Lo and Behold!!! The old girl burst into life first kick and purred like a kitten. Idled it until the fan came on (Fan check!!), kept topping up the coolant. Switched off to let it settle and look at it again tomorrow.

So far, so good.

Nice to see a happy Rickmeister. Well done mate.
RT