Blown top pan gasket and starter

[fiddlersgreen]

Well I guess I spoke too soon!
I said in a previous thread how there was so much negativity against these sleds and that I love mine.
I still love the ride and handling but......
On my last trip I was starting it when it back fired and blew out one of those plugs in the top pan gasket of the motor splashing oil on the exhaust. I started it a few times after with no issues except for the splash of oil but was afraid if I ran it too much I'd burn the thing.
This was my first time on the wrong end of a rope on a Yamaha.
Brought it to my dealer, started it to take it off the trailer and all was fine. After I left they were starting it to move it into the garage it stripped the starter.
I know the starter issue is pretty common but don't know what's up with the gasket.
I never had a hook in 15000 kms with my nytro and have all this with 800 with the viper..... Not so good!!!!
My dealer has been the best through all this and hope to get me on the snow tomorrow. Really, I couldn ask for more.
Im just wondering if it's common for the starter to fail again after the first fail and repair and if anyone has any thoughts about the gasket issue.
Still love the sled but hope this is the end of my troubles!!!

Thanks

 

[cannondale27]

I have seen one that the cam plug came out. Was just chalked up to being poor install. Owner never heard or felt a backfire. No starter trouble.

I am at a loss as to how backfire can be that extreme to blow out a cam plug. Only thing I can think of is a lot of gas in oil. Maybe get a oil sample and send it out to test. Is a cheap thing to do.

 

[fiddlersgreen]

I'm saying a back fire but I think the pop was the plug blowing out cause there was a pile of smoke ...I guess when the oil hit the exhaust.
Backfire may be the incorrect term.

 

[cannondale27]

Maybe there were some plugs installed incorrectly then. Your two starter deal I would look for some way to measure or visualize the contact pattern of teeth on gears. Like setting up ring and pinion on a rear end of a car. There is bluing that is made for this. Teeth should contact in middle not top or bottom and should be straight. Ask a old timer about this. Was very common to shim starters for proper contact on cars and trucks way back. Problem resulted in multiple starter failures. Some even broke.

 

[09nytro]

I would also check to make sure your engine is venting.... It may be pluged and built up pressure and blow out the gasket or plug !!!!

 

[fiddlersgreen]

That's what I was thinking.
Must be pressure built up to blow that out with such force.

How would I tell if it's venting?
Where's the vent on this sled/engine?

 

[cannondale27]

Yes. Check this hose. Maybe it came out of airbox. It vents valve cover.

 

[fiddlersgreen]

Perfect. I'll ask the dealer if they checked it.
Thanks.

 

[cannondale27]

I do not think its a big enough issue to justify in stock configuration but if airbox is removed and filters added to system I would consider putting a small slit in the vent hoses. This will keep most oil in and if plugged hose it will allow pressure out the slit. Messy though and always need to be concerned about oil and hot exhaust can cause fire. I still lean to improperly installed rubber cam plug in valve cover. Would be huge pressure needed to pop them out and I have seen how fast engine is stalled out when vent is blocked off.

 

[fiddlersgreen]

The engine ran fine before and after the plug came out.
Would oil in the air box from Tipping to one side cause this?
I know oil in the air box used to be a concern in the nytros when tipped but not too familiar with this sled yet.

 

[cannondale27]

The engine ran fine before and after the plug came out.
Would oil in the air box from Tipping to one side cause this?
I know oil in the air box used to be a concern in the nytros when tipped but not too familiar with this sled yet.

I do. It could overwhelm that hose I pictured. I think all of us should get the updated oil tank or at least buy the 4 stroke solutions rollover valve and use the tether. The tanks and chaincase covers are junk in both design and strength. Yamaha should step up for any of us who have had a issue.

 

[TD Max]

I do not think its a big enough issue to justify in stock configuration but if airbox is removed and filters added to system I would consider putting a small slit in the vent hoses. This will keep most oil in and if plugged hose it will allow pressure out the slit. Messy though and always need to be concerned about oil and hot exhaust can cause fire. I still lean to improperly installed rubber cam plug in valve cover. Would be huge pressure needed to pop them out and I have seen how fast engine is stalled out when vent is blocked off.

That is a Polaris "fix" from back about 2004 Sportsman as I recall. The other thing they did was to sleeve the hose with a foil type material and loosely zip tie. This was due to dirty environment but also contained the vapors. Effective and simple.