Guys, I'm trying to get a 1987 Moto-4 YFM350 ERU running. It hasn't been run in three years. Before that, it was only used once a year, for seven years. Before that, my grandfather used it to get around his property, but it wasn't abused. It has always been garaged.

When I tried to start the engine, it would turn over but not ignite. I tried that for 10 minutes. Then I pushed the decompression lever, and it started right up (but with the choke on). Then after a few seconds, some smoke and dust blew out of the side of the four wheeler. Turns out, the pipe that goes from the carb to the engine blew apart at the flange. Almost like the intake valve was stuck open and it over pressurized everything.

I put RTV silicon on to patch it, but the four-wheeler still won't run for more than about 20 seconds, with the choke on. If you turn off the choke or give it throttle, the engine dies.

Can a stuck valve be fixed somehow? Lubed up? Can I do this with standard tools that I might use on a car? I don't have experience with ATVs, but I've done work on my own cars like head gaskets and stuff.

Here is a video I took this afternoon, showing the problem...

Thanks,

Chuck

 

The vibration from the motor and age probably cracked it, very common looks like all you need is a new one looks to be the same as the warriors too

 

Problem solved.... I took apart the carb and both jets were clogged. There is a small jet that provides fuel for idling, and the main jet for when the throttle is applied.

I read on wikipedia that backfiring in the intake is caused by a lean condition, and backfiring in the exhaust is caused by a rich condition. So the carb was not getting fuel and causing a lean condition, resulting in the intake pipe blowing. The four wheeler runs great now.

Here is a good video that helped...

Thanks for the help guys.