nox273

Check your radiator cap. It may have let the system build up too much pressure and then spat coolant out when it released.
Happened to a VN900 I used to own.

PeteOZ

You devious minded bugger........But a definite possibility...

Pete

scot in exile

A very good point as it was the same bunch of misfits but alas no as I was standing right next to it when it did it, the bike was lucky it did not throw up on me the last one who did that got a hard kick in the b**ls.

Pig9r

After it cools I would see if it sucked any coolant back in from the overflow. I would also pop the cap and check the level in the radiator. Could be that the cap is bad as nox said. If everything looks fine, I would hook up tuneboy, start it up and run the fan test where you can turn it off and on. If it runs, let the bike run until it warms up and see if the fan comes on by itself. Keep tuneboy hooked up and see what the temp coolant is at. I think the fan kicks on around 180-5 degrees?

honker

Your problem is a simple fix.. I had the same issues on mine last summer. Turns out several Rockets have had the radiator cap go bad. Replace the cap it will solve your problem.The spring gets weak and releases pressure when it shouldnt.

scot in exile

I was going to replace the cap, I will probably wait until Maggie Valley as I will have a pick from about 30 bikes to get a cap from.

GPMAZ

I carry a spare radiator cap in my saddlebags because they can go bad so quickly. If your fan is working and you haven't introduced air into the system its almost surely your radiator cap.

TheKid

Gpmaz has one for you. Everyone mark your radiator cap before MV. You weren't parked in Water Colors making a new suggestion for paint were you?

HellFire

Ya know, when I pulled that ugly sticker off the radiator cap back when it was new, the first thing I thought of was "gee, what a cheap piece of crap".
You guys probably hit the nail on the head, cheap cap+weak spring=wet spot

So is there a better quality cap that fits? I'm sure my day will come.

scot in exile

Ran the bike with tuneboy hooked up, checked fan first all okay, ran engine fan kicked in at about 195degreesF. and cycled on and off as it should.
When the bike was cold the overflow bottle was between the min and max after letting the bike sit and run for about 15min as the bike was running the bottle filled up past the max line when I shut the engine off and as it cold down the bottle went back to the min-max setting as it was when I started.