Www.honda ATV

Junior Member

Posts: 7

Questions on a 420 Engine Rebuild

So there is a bit of a story on this and I'm looking for some people who may have had experience they can pass on about the best way to go about this. So my buddy sinks (gets stuck as opposed to sinks) his 2007 420FM in a swamp made up of very silty boggy material, unit never quits and I pull him out. Its in the water for several minutes, 10 or more and ends up with the engine FULL of water, but never quits, never skips a beat so unknowing to us we carry on down the trail, because one would assume if the engine is full of water it wouldn't run. By the end of the trail ride it gets hard to shift so we decide to check some things including the oil and low and behold water shoots from the filler hole, so several successive oil changes follow to clean out crankcase, and we adjust the clutch and all is well except the silty water has taken it's toll on the rings and now it smokes like a . So the question is, is it as simple as a top end rebuild or should there be concern that once the top end is done the bottom end will go. It has been ridden several miles since we cleaned it all out and no problems thus far with the bottom end, just trying to decide what to do with the machine.

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if it were mine ?...i'd tear it down myself..and rebuild the whole motor. once you get water in the lower engine ?..you can count on more than water being in there !..sand, grit..mud..you never know !. if you don't split the motor and clean it all out the right way ?..your time, and money will be wasted..as your gonna be right back where you started in a few miles !. your call :-).

Senior Member