"Uh oh, those plugs look a little lean!

Well guys, I hope I'm not leading to a total burndown here, but here's the scoop... Saturday the sled ran pretty good, pulled hard, but was running a little low on R's, down around 7300 or so tops, I normally run 7700ish. Went out the next day, awesome fluffy snow, sun shiny day, sled was pulling at full force for the first part of the day, and I will admit, I was pinned alot of the time, and riding it hard... ok Very hard. I was coming in hot for a big booter trying to catch some air and all of a sudden it fell flat on it's face right before I got airborne, just about put me over the bars. Got out of it, feathered the throttle a little bit, and then it was running ok after that, but every now and then it would cut out and pull no more than 6700 rpm. Stopped, pulled the plugs and a light sort of chocolate, a little lighter than normal, and looked extremely dry. Put in a brand new set of plugs, did one quarter mile long WOT pull, shut it off... pulled the plugs. They were WHITE TO YELLOW! Not a hint of oil, and running extremely lean. I was riding with a bunch of smaller short track sleds that were barely keeping themselves unstuck, so me getting towed out was not an option. Tipped it on it's side, dumped the oil out of the oil tank into a bottle, then into the gas tank for a little premix to get me out. Shook it up and took it easy on the trail heading out. Pulled over a couple times, and noticed it was puffing out some blue smoke... I knew I was getting some oil in there for lube. Continued out and opened her up a couple times, and she'd pull 7700 R's. Right on target. Got back to the truck and it was acting like it wanted to seize a couple times, but never completely siezed. Got her home and melted off, did a compression check tonite... 95 psi on both sides. What could have happened any ideas? Taking it tomorrow nite to pull the top end down and see what happened. Will keep you updated as to what I find.

rideharder said:

how does the intake boots look, just replaced mine. one was torn and the other on its last legs. riped or torn boots will cause a lean condition. also is your oil cable broken? might mean you ran out of oil and scuffed some stuff up a bit to loose your compresion. hope i could help.

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At the beginning of the season I pulled the motor out, did the Compfusion mounts, new exhaust bellows, new intake boots, the FBF cable, and whatnot else. Lots of new exterior parts at the first of the year.

94fordguy said:

Wow, that really sucks Steel, I hope you figure out just what it was that almost did her in:face-icon-small-fro

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If nothing else, I have been chewing on a Nytro 4 stroke repower... should be interesting one way or the other! lol

LUBA said:

You know that putting oil in the gas tank will further lean her out right? The oil takes up space where gas should be.

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It was running lean with NO trace of oil, i'd rather have some lubrication in there than none. 91 octane doesn't have that much lubricity.

Shoot!

Well guys here's the damage. Both pistons need replaced, they were both super low on compression which is obvious by the pics, and I also need new reeds, and I'll prob be going with the 32mm updated crank, seals, bearings, and clutch. You can see where the crank rubbed the case, looks like the two piece design isn't so great after all huh Polaris? Also you can see the V-Force reeds that are all chipped up on the ends.

Guess you can only post 4 pictures at a time... heres a pic of the reeds.

Shoot, forgot about that! Dangit I just replaced those intake boots a couple months ago! DAMMIT! What about welding/pinning the 32mm crank to keep it from seperating???