Oops, overheated ec300, what's the damage?
 

Was out yesterday and holed a radiator, didn't notice until a little later, no water in the rad and very little compression, bike wouldn't restart so got towed home. Looks like the barrel has gone a bronze colour (don't remember it being this colour before!).
What's the likely damage??
Thanks

Likely need to replate the cylinder, check the head for flatness, piston, rings, and too end bearing ... maybe;)

PlusOnePerformance

Other than the color how does the cylinder look? Are there any scratches or missing plating? How do the piston and rings look?

Just had the head off, the bore looks ok, the exhaust was full of water, drained the gearbox oil which didn't look to have water in it.
Does that sound like a warped head, passing water from the jacket into the cylinder and out of the exhaust port?

Did it get hot enough to melt the cylinder head o-rings? That could be where the water in the exhaust came from

Er, what o rings!! I think that might be the problem. Thanks

Yep that will do it!

Heh! It's often the simplest things ;) Sounds like you might have gotten lucky though.

Gents, another question, I'm trying to pull the barrel off and need to remove the pin / nut that attaches the power valve actuator plate to the actuating rod. Is it right that this just pushes into the loop at the top of the rod? I was expecting it to be threaded into place, also how does the pin come off ( I' m assuming I remove the nyloc nut and it slides out from the other side of the rod, but it's a bit dark in the shed to say for sure!)

You can decipher alot by looking at the parts diagrams posted at gasgasmotos.es/manuals or back up a step on this page to exit the forum and have a look.

PlusOnePerformance

1. Power valve disassembly/assembly instructions can be found on the main website here :

http://www.gasgasrider.org/pv_disassembly_mattr.pdf

2. You may need to replace your water pump impeller if it is the composite (phenol?) variety. An aftermarket high flow waterpump impeller is available. Water pump seal too...

jeff

Thanks Jeff, are the water pump issues related to running the engine without coolant?

The stock plastic impeller melts if run with out coolant.

Ah, thanks, will change that.

Thanks been looking at the diagrams and it looks like the pin should be welded to the actuating plate! I guess the power valve has been flapping about for some time (sort of explains the pv rattle)

I would also look at removing or replaceing the thermostat housing. I had a real bad experince with one, not sure if it was due to overheating or not but would not take the chance.