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Discussion Starter #1
I have had my 300 xplorer for at least 4-5 years now and I love it. This past summer I went out and got a 2004.5 sportsman 500HO loved the independent suspension but kind of missed my old 2 stroke so I sold it again. The quad is in great shape but the motor was getting low on compression so I am in the process of doing a complete rebuild. I am using a Wiseco Piston, Hot Rods connecting rod, and of course all new bearing seals and gaskets. I don't think there's any power to be made extra with them but I am planing on adding a pipe and jet kit plus ???. The problem is I don't see alot for them AAEN has some and just found RCR (ricks cycle racing) but mostly for the 250cc and 400cc very little for mine. On top of that there's not alot of them around here so none with mods to compare I just trail ride it and plow snow any ideas what parts I should use?
 

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Ok so I got the engine done not installed yet but I did compression test it. On the first pull over 90 psi second pull a little over 120 psi never went higher got to say was hoping for at least 130 psi. I only got the standard bore piston and there was some scaring on the cylinder walls but after honing the cylinder it was almost gone I've seen worst and it was still running at the time of tear down. I am going to try my compression tester just to make sure the one I used was not off. The book say service limit is 115 psi but never said what it should be? Does anyone know what it should be? I should have checked it before tearing it down it must have been low because its a lot harder to pull over now.
 

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you made a big mistake selling the 500, i would of got rid of the 300...like I did last year...good riddance!!.....money pit, it's a dog, so I dont know why your even wasting money in it
engines need 100 psi to run properly, your good on the compression, it's free air cooled so it doesnt make alot oif power like a liquiid cooled 400
my intake boot ripped and it blew the piston so i sent it out to summit racing and had it bored and a new piston, still had a hard time starting and yes still a DOG
 

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Wow I was thinking the other way around my 300 is almost 17 years old that's the first the motor has been touched other than 2 front struts and the rear chain never had a issue with it. I spent more on the sportsman in 3 months than I spent on this one doing the engine. As for being a dog i'm saving almost a hundred pounds on the sportsman so if you do the math the weight to power ratio is almost the same 21 lbs per hp on the xplorer and 19 lbs per hp on the sportsman. I had a buddy's 2005 sportsman 500 ho carb. model we raced them maybe 400ft. stretch he pulled me a half a quad length off the line and that was it I stuck with him my front tire even with his floor board to the end of the stretch. I also find the xplorer wheelies a little easier than my sportsman did also. By the way my sportsman was jetted and piped although I never raced them together when out riding with my wife I never shook her on the xplorer so other than 10mph on top end didn't see the difference? Just my opinion I like my xplorer better.
 
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