Willasan
New Member
To start off, I've got about 1300 miles and counting on my RC390. I live near San Diego, and regularly like to go hit up Palomar mountain and the surrounding areas that are in the 3000-6000 foot in elevation range. When I first got my bike, I took it to the top of Palomar (6000ft) and it puked A LOT of coolant when I turned it off. It was also around 85-90 degrees and an uphill climb. The next time I rode down in lower elevations I pushed it a bit and it also puked a little bit out of the overflow when I turned the engine off. This wasn't nearly as severe, and I'd overfilled the overflow slightly, so I wasn't too worried. After this during my break in service, the oil was changed out with Motorex full synethic and fresh Motorex coolant was put in the bike. I haven't had any more overflow issues until this Sunday. Again while on Palomar mountain I got a bit of coolant puke out of the overflow tank when I would stop the motor. It's not a lot, just enough that I have to watch I don't ride over it on the way out. It was hot again, 80+. I was pushing the motor fairly hard, but even if I let it slow down before shutting it off it still puked. This would only happen when my motor is off and been sitting a little bit. I've never had it do this down in lower elevations (granted I haven't gone at it nearly as hard) My question is this: Is this coming from the load (heat) placed on the motor combined with the elevation? Should I be worried about this? Once I turn the motor off it gets enough heat through the coolant to go through the radiator cap into the overflow I'm guessing. Maybe I need a new radiator cap...