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Discussion Starter #1
Yep, i went to the radar runs yestaday, and i got 91.23mph on my '92 440 XCR.
Then i was out ridin taday, and it backfired once and was really doggin it, do i drove it home and let it idle for a couple minutes, and i heard a loud grindin noise........Guess what boys!!!....i seized a piston. Well i'm pretty sure i've got some damage to my cylinder, so i'm gonna have to bore. I'm not sure if i should bore both cylinders or just one? What have your experiences been like. Also how much does it cost usually. I dont plan on doing it till summer. How much should i bore it. Is there gonna be a horse power gain since my rings were very worn. thanx!

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I would do them both, since you've got it apart anyway

yes, HP will go up a bit.



http://www.bolliger-mabillard.com

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that sucks smxcr, but sounds like you did good in the radar run! how far was the run? i pulled 70.3 mph last year in a 1000 ft run- with some, well, we'll say SERIOUS traction issues.


When in doubt- Throttle out!

'99 XC SP 500
 

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i was going to bore just one with my sled, but the machine shop screw up and overbored. So they fixed it and did the other one for free. For the price difference go for both.

 

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Hmm, have you looked at the cylinder yet? If it is not bad I would just get it honed out.

On another note. I hade my new 700 on Lake of the Woods today. Just messing around on some island drifts. After that I decided to get some speed runs. I hit around 108 on the speedo, but believe me, there what quite a bit of throttle left. It wasn't even wound out yet. I will test some more next week. Too bad I can't get my hands on a radar gun. Oh yeah, after I ran back and forth a few times I stopped to talk to friends. After that I started it and tryed to take off but it wasn't good. It made bad sounds in the clutches. I opened the hood and the secondary clutch was still wide open. So, I think there is a broken spring in there because I can hear parts moving around.
No more riding after that.


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lol, sounds like me!!!!

Polaris says that you can go up to a .020" difference between cylenders...

-Dean
 

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Where did you find a place that had radar set up. I haven't found one here yet. Are there sites on the web to check?

Live to Ride! - FrozenSmile
 

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SmXcr, good run. Was that in the 1/4 mile then? Plus, i was wondering, if the radar said 92, what did you speedo say??? I am curious as to how accurate it is.
 

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Discussion Starter #9
Sorry i took so long to reply........... the strip wa about a 1/4 mile long on a local lake, they are put on by the local snowmobile club. My speedo said about 97, which i new would be off. I wasn't the fastest in the 440 clas though, a 440 polaris on the edge chasis go 99mph and a 98 440 xcr got 96. I couldn't believe that i got 92 out of it. It was very well groommed, and a real thin coat of ice. It was perfect! I mean perfect conditions!!!!I found out what happened, the rubber flange that goes from my carb to engine was all cracked up, apparently to much air was getting in, leaning out the mixture, so it burnt up. There was cylinder damage, so i am gonna bore both out 30 over. Damnit, i saw those flanges this summer and new i should have changed them. I screwed my self over! I'm diggin out my drivers ed money,so its going to my mechanic hopefully soon, so it will be ready for the radar runs in feburary.......

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Edited by - smxcr on 23 Jan 2002 15:55:46
 

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Hey, nice lookin web page smxcr! Too bad about your sled though, I'm sure you'll have it up and running in no time.



1997 XLT SP 600
 

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Hey there smxcr! I would bore both holes out the same. I know polaris says you can go up to 0.20" over on one cylinder, but for what it sounds like you are doing with your sled ,I would do them both the same. The reason being that you are going to have an engine that is out of balance, because of the bigger piston in the one side. This will put undue stress on the crank, and if you are doing radar runs and holding it wide open lots this could be a big factor.Another option is to bore out thebad side and put a sleeve in bringing it back to stock piston size. Hope this helps. Good luck.
 

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Yes I would do both of the cylinders while it is apart.

Personally I would only bore the minimum necessary, you never know what will happen, you may have to punch it out again before you want to.

(o;

DNO.
 

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Discussion Starter #13
I don't know about you guys, but this winter cant get any worse. Little snow and alot of problems.My mechanic called me wensday and my crankshaft is gone. He said it is very common with polaris 400's 440's and 500's of the late 80's and early 90's, but not until they hit about 8000 miles. Mine went at 5, 811 which is early because my pipes make my motor work harder for the xtra powa. Also my motor is dew in for a rebuild. I'm boring it .020 over. He gave me a great price, $1000 including labor. If i would have went to the dealer i would have payed 1700. I know i shouldn't put that much money into my machine but theres somthing i just love about my 92 red racer

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Do both its apart mind as well get it done and then you can ride when its time not worrying about stupid stuff later.
 

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Yes, both cylinders. If you bore one and not the other, than you will knock the engine out of balance and it will shake itself to death. VERY dangerous. plus you will get some decent gains in the powerband.

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