vt700 puking coolant

[welby]

85 700, run the bike up to temp, cooling seems fine, not overheating, fan working, but the second I shut it off coolant starts puking out of the overflow tube.

I'm waiting on a new rad cap and thermostat that I ordered. In the mean time I'm going to flush the coolant and burp the system anyway.


It's also been hesitating once it's warm, mostly in the mid-upper rpms with 1/2-full throttle applied.

I had a similar problem last summer and adjusted the air/fuel mixture screws and it seemed to remedy it. I'll be pulling the plugs, but I'm thinking of a carb rebuild/re-jet in the near future. (only mod is a K&N in the stock airbox but that was done before the adjustments).

Any suggestions appreciated to help me move this process along.

Thanks

[SHADOW 1100T]

Check the coolent level in the Rad. it should be full then check the overflow hose for ANY cracks, replace it if there is, if it isn't air tight when the coolent gets hot it will just dump on the ground leaving a air space in the Rad when it cools. On a hot engine when you shut it down is when the coolent gets it's hottest, you say the fan runs well if it doing that when running the coolent has got to be low. Top everything off, the over flow tank should be to the cold mark and run it to see what happens.

[ExTex]

My 500 did about the same. It was a faulty radiator cap.
I hope that solves your problem too.

Ride Safely

[welby]

Originally Posted by SHADOW 1100T

Check the coolent level in the Rad. it should be full then check the overflow hose for ANY cracks, replace it if there is, if it isn't air tight when the coolent gets hot it will just dump on the ground leaving a air space in the Rad when it cools. On a hot engine when you shut it down is when the coolent gets it's hottest, you say the fan runs well if it doing that when running the coolent has got to be low. Top everything off, the over flow tank should be to the cold mark and run it to see what happens.

Thanks for the tip, I pulled that hose and replaced it just to be safe and will be replacing the grommet that goes into the reservoir as well (when I find the right one). The coolant was a tad low because of the spewing it was doing out of the overflow, the fan only cam on once for a bit, and it never really got that hot. Topped everything off and burped it and it still pours out the overflow.

My 500 did about the same. It was a faulty radiator cap.
I hope that solves your problem too.

Ride Safely

I kind of figured as much, still waiting on the cap so we'll see. Can't really be much else, everything looks good, compression test read 137/142 so it's not a head gasket. Thanks for the insight fellas, just needed some reassurance that I'm not going crazy.

[Stallion409]

Not sure if you've resolved this issue yet or not - but my overflow tank was puking coolant as well. Check the following assembly to make sure everything is connected and sealed properly:



I ended up having to replace my "level tube" (#12) because the top was dry/cracked and the "joint tube" (#1) didn't fit into it correctly.