Just today had a k100rs delivered and it has a red warning light constantly on ( a warning triangle lit up).
Thought bulb out warning ? not sure  as no bulbs seem to be out .
Its the one above the Neutral light.
As yet I have no manual so asking for your help.

Cheers In advance of any help. 
John

For the light to go out the front and rear brake needs to be activated. If you have a faulty brake switch front or rear the light will not go out.
Regards Martin.

Check 

1: Check the front brake activates the brake light. If not, suspect the front brake switch is faulty.
2: Check the rear brake activates the brake light. If not, suspect the rear brake switch is faulty.
3: If one works and the other does not, the non working one needs a new brake switch. Not expensive.
4: If both work, take out rear light and clean the bulbs, bulb holders and contacts. There are two knurled nuts inside the rear cowl that you unscrew by hand to get the rear light off.
5: If neither work check the rear brake lights up with a separate live wire.
6: If that works you likely have 2 faulty switches. Before anyone says you won't find that, thats exactly what happened my RS when I got it. Both switches died at the same time.

The red warning needs both front and rear brake switches working to test the circuits to get the light to go out. If one is faulty it won't go out.

There is also one on your clutch lever linked to the ignition system, you need it working so that you can start the bike with the clutch lever pulled in. Otherwise you need the green neutral light on.

Also can you put in model year, RS had lots of changes going from early 2v to later 16v engine but the above will apply to either.

Does the bike have LED tail light or brake light bulbs?  If everything works properly that may be the problem.  LED's look like bad bulbs to the bulb monitoring unit or BMU.

Point-Seven-five wrote:Does the bike have LED tail light or brake light bulbs?  If everything works properly that may be the problem.  LED's look like bad bulbs to the bulb monitoring unit or BMU.

Forgot that one......

It could be simply that the OP has not activated both brake levers.

Another possibility is that there's a short.

Thank you for your help guys
I'm not with the bike at the moment but will try those solutions out when i get back from Holiday,
The bike is a 1992 abs model.

Cheers John