[SpudRider]

Originally Posted by roots

Hey Spud, my cap has been an issue since the beginning. It pops off easily when tightened. I get it snug, not too tight, and then I find it popped later. I assumed my periodic coolant loss was due to spillage. The last time I was refilling I did notice a tiny vent hole in the cap, so even if the cap is fully sealed the system should be able to vent through the hole. My cap threads appear to be fine when I look at them, so I have been suspecting the bottle threads are "bad". I just haven't had the time to pursue it further. I switched from filling the "overflow" bottle through its cap to filling through the radiator cap. If you have the bike on the side stand and fill it slowly with a funnel, it overflows into the bottle just before it would overflow out of the radiator (I picked up that technique somewhere from another RX3 owner). I can unscrew the radiator cap without removing any panels, so that seems to work better for me.

It appears you also have a bad overflow bottle. Thanks for mentioning the vent hole in the bottle cap.

I see you are using RJ's method of filling the overflow bottle. If you don't need to remove the fairing to unscrew the radiator cap, you must have small hands.