My 03 Rancher 350 has always ran great. Then wouldnt start checked spark,fuel etc. then found it had 0 comp. Maby the Decomp. is stuck open. Where is it, how do i check it?

 

Bad news, if you have 0 compression it's not the decomp valve. The engine needs some compression to start so the decomp only bleeds off some of the compression so it's not as hard on the starter.

What happen? Were you riding and it just quit? Did you park it and now it just won't start? What does the plug look like?

If you have 0 compression like you say, my bet is on valve gear. Busted rocker, stuck valve ect.............

First thing I would do is a leak down. This will point to the exact problem. If you don't want to do that, then the next thing I would do is pop the valve cover off and look at valve motion.

 

First thing you should check is if a Fuse is blown. Then if thats not it go on to the other stuff. [img]i/expressions/face-icon-small-smile.gif[/img]

 

Aaaaaaaaaaa, how could a blown fuse cause no compression?
Ring fuse?[img]i/expressions/face-icon-small-happy.gif[/img] Valve fuse? [img]i/expressions/face-icon-small-happy.gif[/img][img]i/expressions/face-icon-small-mad.gif[/img][img]i/expressions/face-icon-small-shocked.gif[/img][img]i/expressions/face-icon-small-tongue.gif[/img]

 

It's more likely a compression fuze...


[img]i/expressions/face-icon-small-happy.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img]

 

Dang, over looked that one...........Thanks IV!!!! [img]i/expressions/face-icon-small-wink.gif[/img]

 

I agree with dotorturbo first thing i would do make sure the spark plus is torqued thentry it if this isn't the fix ! You didn't say if you were riding when this happened, or if it has set up for any peroid of time like 3 - or 4 months with out riding; if this is the case then it could be a stuck valve or stuck or broken rings. On the rings you might try removing the spark plug spray some penitrating oil in the plug hole then add a tablespoon of engine oil put the plug back in and let it sit overnight ! Then remove plug and turn over the engine a few times, if oil doesn't blow out of the cylinder go to the next step - remove the valve access cover's and check the valves like dototubo said. It could be something bad, or simple like valve adjuster loknut loose or stuck valve. It doesn't take long for a valve adjuster locknut to lossening if it wasn't torqued the last valve adjustment. And if you didn't do the job yourself the dealer may have let a kid do the work, this happened to me with my dealer ! The proper valve spec's on 350 hondas are Intake: 0.03 inch and Exhaust:0.04 inch . good luck and keep us posted ! And answer some of the questions asked by doctorturbo and my self, a little more info would help out alot.................williebee

 

By all means check fuses, but that's a new one on me !...................williebee

 

AH the valavle clearance on a 350 honda is NOT .03 and .04, mabe on a old 350 foreman, but a on a push rod type motor like this it's is .06 on both. None of Honda's push rod motors have less that .06 on intake or exhaust. Most likely what happened with he's motor is that the exhaust valavle seat has came loose, and he will have to replace the head.

 

Suddenly means............Was running fine,Stopped for lunch, No start, Checked every thing, Found 0 compression!