yamaha 04 tlrc90 dead cyl.

[cgj13579]

Engine started running rough and quit. Restarted still ran rough at idle.Had good stream of water. Checked oil inject seemed ok.Checked compression bottom cyl. only had 40 psi.Also there was water in bottom cow.after oil inject test Engine had ran hot on last trip. I think head gasket is blown? Any other thoughts.

[99yam40]

If fuel pump leaks into #3 through pulse port it can wash the oil off and cause major problems.

If cylinder is running lean fuel/air mix it can damage things also

Over heat can damage piston

All you can do is open it up and have a look to see what has happend

[cgj13579]

Thanks will check the fuel pump when I tear it down. I had not thought about pump.

[cgj13579]

Engine started running rough and quit. Restarted still ran rough at idle.Had good stream of water. Checked oil inject seemed ok.Checked compression bottom cyl. only had 40 psi.Also there was water in bottom cow.after oil inject test Engine had ran hot on last trip. I think head gasket is blown? Any other thoughts.

Opened it up found broken ring on 3 Ring had broken the land between the rings. There was a small scratch at the exaust port the rest of the cyl. looked ok. Cleaned cyl.s and micked all were at upper side of tolarance 3.230 was the worst on cyl 3.Question should I bore .010 or go back standard?