I recently pulled off my radiator hose while trying to install frame sliders on my bike and lost a good amount of coolant. Not a decision I'd make again but, there it is... Now I guess I need to top off and bleed the air out. Does anyone know if it is OK to just add the new coolant to the old or do I need to drain all the old and replace with the new?

I'd just top it off. You need to add it via the radiator cap itself, not just into the overflow container. Once it's full again, it may take 2 or 3 short rides to get fully up to temp and force most of the bubbles out, before cooling down and repeating the process. On a bike with a temp gauge you can see this behavior, but as we only have a warning light, it's unlikely the engine will ever get to that high a temp to light the indicator.

No need to drain, that sounds good to me. Got it about the radiator cap and overflow. I saw that in the Service Manual. The manual also describes running with cap off while bubbles work themselves out. So, is the process you describe to fill, re-cap, ride to heat up, let cool down, and then remove cap once bike is cool?

When you first fill it up, running it with the cap off for a short while while some bubbles make their way out isn't a bad idea. After that, turn off the bike, make sure it is still filled all the way to the top, and replace the cap. You're pretty much done at that point. Check it after 2 or 3 rides if you want to make sure that it is still filled to the top, but if your cooling system is working correctly and there was enough in the overflow, everything should be peachy without you doing anything else.

Thanks much. I'll get on that tomorrow so that I can get riding again ASAP!

You should consider premixing the antifreeze with water in a 50:50 solution. Also, if you have pets, be careful and not spill the antifreeze where they could drink it. It is very tasty and very deadly. Any mixture that you have left over can be stored in a sealed container.

You should consider premixing the antifreeze with water in a 50:50 solution. Also, if you have pets, be careful and not spill the antifreeze where they could drink it. It is very tasty and very deadly. Any mixture that you have left over can be stored in a sealed container.

+1 - since you mentioned looking at the manual, you probably already saw that it calls for the mix, gut just wanted to be sure :)

I find that by leaving the cap off of a running vehicle it (most of the time) will overflow. Keep some rags around.