Gasgas ec 300 knocking when hit
 

Hi all .
I’ve got a 2018 ec300 with about 25 hours on
I entered my first enduro yesterday in the uk .
All was going well until it developed a very bad knocking noise so
I pull Over as I didn?t want to damage the engine any more and left it cool down
For around 10 minutes. Tried to start it and all was good no knocking and run
Perfect for another few minutes until the really bad knocking come back .
Any way I managed to get back to the van but still have no idea what the knocking noise was or what it could be .
Any one had anything the same . I?m was thinking bottom end and maybe the bearings have failed But wouldnt it do it all the time not just when it?s hot .
Thanks all

I'd take a look at the piston/cylinder.

My bike made a knocking noise and it turned out to be piston slap. I replaced the cylinder and I *think* there's still a bit of slap at certain situations.

Check the rotor bolt and the right hand side crank nuts for torque first before pulling the cylinder. There was a recall on the right hand crank nut and the rotor nut has been found to be loose a few times.
Make sure you actually remove them and cover them in loctite before retorquing them.

Usually I take a look at pistons trough the exhaust. If the wear resistant coating is gone, then the lid as to come off.

Popping the cylinder out of these ec's really isn't that bad either. I think I went from an open engine (when I replaced the piston) to a running bike in about an hour.

I agree but 25 hours on an Ec300 should not need piston etc unless it has been drowned, dusted or cooked.

Yeah it's not a KTM.

I put a piston in ten years ago. When I unzipped it to change a main bearing, the ring, which I had gapped to spec was 1/3rd through its service life. I dont ride this bike every weekend but,

The original piston 3 years old was worn, but looked like it had something through it.