Quote:
Originally Posted by Daox
Perhaps its leaking by? Wouldn't take too much flow to cool that whole engine I'd imagine.
Nice looking bike btw.  |
You hit the nail right on the head! That is exactly what it was doing. The O-ring I pointed out is just to keep coolant from leaking out, so it is unrelated to this problem. You can shake the thermostat housing and hear the thermostat rattling around in there. I did a flow test by pouring water in one side and seeing how fast it would flow out the other side. Well, it flowed a whole lot more water than what the little bypass hole in the thermostat should be able to flow.
I took it apart and put a spring in there to put pressure on the thermostat so it wouldn't move. Put it back together and voila! No more rattle, and it passed the flow test too. So that's what the problem was. I really do not want to rely on the spring though, it could come loose at any time and destroy the water pump.
While I had it apart, I put it in some hot water to test opening temps. It appeared to open at 172F, and was fully open at 185F.
New thermostat is on its way, REALLY HOPING that it won't rattle like this one does. Considering the slapped together nature of this bike in other areas, it is certainly possible the PO just threw a thermostat that "fit" in there.