NAPA auto stores sell Pentofrost NF which is the same as the blue BMW OEM motorcycle coolant. The honda coolant (Green) I have used but now that I found the NAPA stuff that is all I use in the bikes. The Pentofrost is not diluted so get some distilled (not deionized) water on the way home too. 50:50 is good but if you live in an area where it does not get nasty cold 60% water is a way to get more heat transfer. Your RS has minimal radiator surface area for the bike. They tend to bounce of the fan if you are going less that 50 mph.
Welcome to the site by the way.

 

Thx, yes water does better at heat transfer than even coolant. I live in AZ so ambient temp could be 116 plus pavement radiating fierce heat when stopped. It is like a furnace.

 

I did well with Honda pre-mix coolant. Replace the thermostat at the same time, mine didn't completely close resulting in the engine not reaching normal temp on cold days.

 

Beech, I'm curious as to why DI water wouldn't be OK, as it's as close to pure H20 as practically available.
As to the coolant, Prestone from Walmart is fine. Been using it since my '03 was new with no issues.

 

Usually distilled water is purer (has more of its minerals and organisms removed) than deionized water. So better choice is distilled to lower the chance of forming scale contibuting to overheating.

 

No nitrites/phosphates and low sillicates is the BMW spec.Easy to find and not that expensive.Pissy yellow for the Recochem brand I use but easy to color with a few drops of food coloring.So yellow + blue coloring I run nice green coolant.
Early Ks had the regular green coolant as OEM spec.Many suffered from failing seals/corroding pump shafts.BMW changed the coolant spec from green in the early 90s to what is now spec.Seals and shafts problems pretty well disappeared after that.

 

In sum...I'll go bmw spec with 50% distilled.

 

It is a good topic. I'm old school and prefer distilled water. Though I know the the other water is recognized as a dilutant for commercial anti freeze. The coolant is a lube for the water pump seal which is needed. But here is an article that has me thinking about going even lower on the scale with my antifreeze ratio. I've seen others too. Lots of great articles on the web of course. And there are additives for increasing heat transfer in the system too. Change your coolant at least every 4 years. I'm way overdue for my take stuff to the dump, truck that gets less than 300 miles a year.

SparkPlugs.com: Quest for the Ideal Coolant Ratio

www.sparkplugs.com

 

Bmw motorcycle coolant specification is : GS94000.

That specification goes for all bike's 1985 an onwards.
Bmw OE coolant is Basf Glysantine G48. Nothing else.

There, no color , any type or brand can choose whatever color they like, there is no standard regarding color, it was supposed to be but all manufacturers did it their own way. So choosing coolant by color can not be done, hence coolant should be choosen by specs just like motoroil.