Thoughts on diagnosing coolant fumes...

[benVFR]

Thread title says it all.

Got my bike running last night for the first time since I crashed.

The VFR has side mounted radiators, the right side one was obviously impacted, but for the most part the radiators are "soft mounted", there is very slight damage to the fins in one area, but I can't find any leaks.

When the thermostat opens I get fumes in the vicinity of the radiator fill cap. (Which is actually not mounted directly on the radiator.) Can't find a leak though. There has been no drops of coolant or anything like that on the floor in a month of sitting + work. I poked around in all the crevices, etc.. and can't find anything either.

My thought looking at the parts fiche is that I may have inadvertently pinched the return line that goes from near the radiator cap back to the reservoir on the other side of the bike, causing the pressure to vent out of the cap. (I had the tank open and the intake apart to verify no dirt/gravel in the airbox) I'm going to check that. Does this make sense?

There is no visible damage on the hoses, filler neck, or cap itself.

After that all I can think of is:

1) Loosen, clean, and retighten the cap.
2) Replace the cap $20
3) Take it to a professional for a pressure test

Unfortunately with 2 radiators the plumbing seems to be much more complicated then usual.

[TLRMan]

If you have residue of coolant at or around the radiator or cap, when the thermostat opens, it allows the HOT coolant thru, the residue will give off a coolant odor when it gets hot. Did you add coolant to the bike recently, or spilled some?

[benVFR]

So I think I was just stupid and paranoid.

I left the bike running a bit longer this morning to watch it heat cycle all the way to make sure the fan is working.

The smell seems to be going away.

I think coolant spilled out of the reservoir overflow line onto the headers and/or other spots on the bike when the bike was nearly upside down on the hill going up Turn 4....

I talked to the Service dept. at the honda dealership down the street and they said ride it around and see what happens.

The thermostat opening and me smelling stuff near the cap is probably nothing to do with it... just me grasping at straws.. probably has more to do with how fast things are heating up and the air just happening to be wafting up in that area.

Thanks for the help.. if it doesn't go away I'll definitely be asking a few more questions.