Hell TRX Forums. My name is Kreg and this is my first post here. I recently decided to buy a 400ex. Havent owned a bike in 8 years. But always wanted a 400ex. Previous owner did a top end with new jug on the bike. It was quiet apparent something wasnt right with the motor. Tapping like noise up top. So i got the bike for cheap and dug in. Right away I could tell the timing was off. As i got further in, i was able to see the exhaust valves had been contacting the piston. I'm thinking i can get away with keeping the piston and jug. They dont look cracked of scored. Maybe just a re ring and hone. The timing chain appears to be stretched. One tooth in either direction puts it out of time in both directions. So timing chain, valves, valve seals and and cam shaft. The lobes on the camshaft look pretty work. Just wanted to ask if you guys would do anything else while I am in there. Mechanically inclined, but new to working on 4 stroke quads. Pics and videos to come as soon as I figure it out. Tried to post before and deleted all the text.
Valves Contacting Piston
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https://youtu.be/yBb8Tb_cZvA
Link to youtube video. This was before I tore it down. Guy said after the top end, the clutch was sticking. So he removed the clutch cover to look at the clutch. He replaced the seal but only removed 60% of the old gasket. So I replaced the clutch with a genuine honda clutch before I got into the motor.
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