Did my routine maintenance check and everything was great until I opened my radiator cap. Coolant was murky green with a tiny/minute bit of yellowish brown residue at the top. I check the backside of my radiator cap and it has this thick glob of light tan brown stuff. It had an oily feel to it. It's the size of a quarter, no bigger than a half dollar of this goob.

Is my oil mixing with my coolant? The coolant is dark green and my bike doesn't overheat at all. The tan glob stuck to my cap was what alarmed me.

My oil is fine. It's not milky. Looks new still and it's been about 2500 miles

 

Clean it and see if it happens again.

 

Sounds like its just some gunk in your system to me. If the coolant itself is the nice green color I wouldn't worry to much just keep an eye on it.

 

I'm crossing my fingers that it is just gunk. Tomorrow morning, I'm going to open up the cap and see again. I'm going to drain the coolant and refill with new coolant and see if the problem persists. If it does...."CBR 600 F2 for sale". And Subyman1440 will be on the Honda Rebel Forums Hey look on the bright side..it's still a Honda right? I hope this isn't happening lol

 

Have you checked your oil? If your oil looks like a mocha you got trouble.

 

My oil is fine. No problems at all. But I did check my radiator cap again today, and this white/light tan gunk appeared on bottom of the radiator cap again...However, I still have not flushed the radiator/engine block yet.