Hello, new to the forum here. I have a 92 Polaris trailboss 350L. Overall the general shape is neglected, but is complete. Racks are straight, plastic is complete. I have been having trouble with it back firing out the exhaust when trying to start it, so I ran a compression test. It came back to about 75psi. I'm thinking this is low, usually I like to see at least 100 or better. I'm on the fence about rebuilding it, or if there are other things I should be looking at also. I already ordered a carb kit, and fuel shut off, air filter assembly. Compression was taken with the throttle wide opened, and four pulls on the handle. Everything works on this machine, and would like it for ice fishing. Anything I should look at before a top end?
92 Polaris compression
92bosshog
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Lost me on that one - I can't find what you are calling a "decompression" hole in the head?
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Now I'm lost even worse - the cylinder is filled with liquid and there is no holes from the combustion chamber to the outside of the cylinder. Those fitted with compression releases were always on the head. HELP ME - I'm need to know what it is you are talking about
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Yeah - I just learned something too, but the 350L doesn't have a compression release that I can find in any of the service literature or on the parts breakdown
On the two strokes it's more of a bleed hole in the cylinder. No levers or valves.
Most sleds now do use power valves. I believe the original 2001 xc 800 liberty twin did not have powervalves but did have decompression holes.
When the big twins (800/900) came out they were bears to start when cold.
An old trick was to put the choke to full before shutting them down for the night. The theory was the extra fuel would wash the cylinders down of two stroke oil. Alowing it to turn over easier on the cold mornings.
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Yeah, I did a quick scan of some of the threads and apparently those holes allowed some of the compression to leak off for cranking etc. The guys blocking them off were talking about it adding some bottom end power but that the difference was unnoticeable on the top end. I'd never heard of this before but it makes sense to let some pressure off when the piston moving slow as in starting but making no real difference at high RPM.
Got it going finally. Runs well I would say, so I'm happy. It fires right up, but still is a little iffy on the idle part. Probably needs a carb cleaning. However, when I put it in reverse, it will die unless I'm holding the override button. Is this normal?
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Part # 3130439 - about $11.30
Just put the part number in the Ebay search box - cheapest one I saw was $11.25 or best offer and free shipping
Just put the part number in the Ebay search box - cheapest one I saw was $11.25 or best offer and free shipping
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Thank you, my throttle cable frayed and the throttle got stuck wide open. Really fun.... Haha luckily it's icy here and it just spun out. The spring must have been bent and it wore on the side of the carb. The barn is fine, just the spring is bad.
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I won't say normal since it is not supposed to do that. It should run in reverse, but sputter and pop if you try to go too fast. Unless the over ride button is pushed. It is not uncommon however for the machine to die when shifted to reverse unless the over ride button is pushed. Both my 325 machines do the same thing. I added a speedo kit to one which replaced the reverse limiter and for a while it didn't die every time I shifted to reverse. Worked like it is supposed to for a while, now it comes and goes. I just get into the habit of holding the button when I shift to reverse.
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Disconnect the black ground wire from the Rev limiter (#33) and see if it does it. IIRC it ties into the cdi to cut power in reverse unless you hold the button. When it goes bad it'll just kill the engine rather than intermittently cut ignition. If that keeps it from quitting, you need a limiter. Sounds to me like that may be the problem.
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