Gas Gas Maintenance - 1

Piston from my 2003 Gas Gas EC300. Some carbon dragging, from the power valve, on the exhaust side of the skirt.

Buying a used bike is always a gamble unless you know the previous owner. Even then you might know them, chances are good you'll find a hidden surprise or two. The previous owner of my 2003 Gas Gas EC300 was one Doug S., whom I've known for a few years. In fact Doug was the original owner of my 2001 Gas Gas XC300 (I'm the third owner of that bike). I'd been warned that Doug's mechanical skills are on par with those of an 8th grader who sniffed too much gasket remover in shop class. While I have yet to confirm this warning, I will say that Doug never did any mechanical work to the engine in the four years he owned the '03 Gasser.

I should have listened to my inner voice when it told me to do a top-end. Actually I should've listened to a lot of things my inner voice was telling me. However, with limited time to perform preventive maintenance I ignored my inner voice. The result of this misfortune can be seen in these pictures.

Here you can see the main culprit. The compression rings are stuck in the ring grooves on the exhaust side of the piston.

I'm not going to make any excuses or blame the previous owner or the bike. This failure, and my subsequent DNF at the Rocktoberfast Enduro, was the result of my laziness. Prior to the Newark Enduro I should've changed the main jet from a 175 to a 178. While the 175 was fine for short full-throttle bursts, running WFO in top-gear through open fields and back roads was a big NO-NO. When the air filter became clogged with dust, this actually prevented air flow into the engine. Less air meant the engine ran hotter. The combination of all three caused the rings to stick in the grooves.

This week I'l be putting in a new piston, cleaning the exhaust power valve, installing new reed valves on the intake and repacking the silencer. In case you're thinking I'm forgetting something, I already installed a 178 main jet in the carburetor.