# Think I figured it out.... maybe?



## Crazy Axe (Mar 11, 2007)

So I've been sitting here pondering why my machine is running hot and I think I finally wrapped my head around it. There is a slight exhaust leak right where the manifold bolts to the cylinders. I figure when I get on the pipe it's pulling some fresh air in when the charge goes back into the cylinder. So I'm going to try replacing the gaskets there. I would try to put some sort of sealant on the existing ones but the only "exhaust gasket goo" I've seen says "Not for use where product will contact fuel" or something like that. I figure there will be at least some unburnt fuel working its way out there so that might not work. 

So what do you guys think? Am I onto something here or still chasing my tail? :banghead3:banghead3:banghead3


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## SalmonBum (Feb 28, 2001)

I know it will lean the fuel mixture out, no sure it solves overheating

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## Crazy Axe (Mar 11, 2007)

Here's some pics to go along with... Was wondering if I've got some bearings bad behind the secondary on the jackshaft, and on the drive gear shaft where the speedo is. I know Polaris is notorious for failures at the speedo for that bearing. Also the pics show where the exhaust manifold was leaking.


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## grouly925 (Dec 6, 2006)

Not sure on Polaris' but when your speedo quit working on an arctic cat it was time to change that jack shaft bearing. Have you had the coolant out of the sled lately for any reason? Has it ran hot since you got it or since there was work done on it, or something else? Some sleds have air traps in the cooling system and require you to elevate the front of the sled to get all the air out of the cooling system, especially the front heat exchanger (the one that does the most cooling). What model sled is it and what engine? I belong to the snowmobile.forumcom forum, lots of friendly people there and some very knowledgable small engine folks.


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## Crazy Axe (Mar 11, 2007)

There hasn't been any work done to it that I know of but the guy I bought it from was sort of shady.. I probably should have walked away from it but something drew me to it.

Anyway.. It's a 99 Polaris XC 700 SP. I have not tried elevating the front of the sled yet, but heard that is standard procedure for bleeding air from the system. Not sure there is a front heat exchanger I think the only heat exchangers are above the track under the tunnel. The speedo still works but if it's going to be a problem with the grease coming out, I'd like to replace the bearing before I go on a real long ride. I posted a similar post on hardcoresledder.com and I'm also waiting for an opinion from a guy I know that knows a LOT more about this stuff than me. Being a n00b is no fun  :lol:


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## outside4me (Jan 13, 2012)

eeeeeew that's gooey ...

Hi , been reading your post .. congrats on the sled  .

couple things ..
those reeds are ok , one is the top and the other is the bottom .. 2 sets, 1 per cylinder.

manifold/ Y-pipe leaks will burn a sled down on a crisp day , but that's not your overheating problem. Yes it will be hotter, but piston failure will come before cooling system fails to cool it .... air leak makes a hot spot.
Cooling system controls overall temp.

From reading your other post .. I would pull the recoil and check that pump belt . Where you there when he swapped out the broken recoil ? 
... Air bubbles can be stubborn to burb out , I make sure its topped of and on the 1st ride ( normally a little shake down run around home ) find a bank to nose it up on for a bit , then let it cool and re-check.

Those bearings look rough, clean up what you can and get the tension off the shaft , belt, track . Try to wiggle it , you'll know if its shot , should be smooth and no play.

Nord-ride is a great place to deal with , bought all my toys there ... very good people there .

... and last , where in burton are you ? ... im real close might be able to help you wrench and get you on the snow


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## SalmonBum (Feb 28, 2001)

For the few bucks they cost, I would replace those bearings. Your not too far from me. If you want bring your sled down and we can replace all the drive and jackshaft bearings in an eveing. Its been awhile since I did a Poo of that era, but I have done many in the past.


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## MossyHorns (Apr 14, 2011)

The left drive bearing is a sealed bearing, but the flange that holds the bearing has a grease fitting. The grease in your picture is from the flange. I replaced my drive bearings in my 2005 Polaris (7000 mi) last year. My bearings were starting to feel ruff when I inspected them. The only real way to check the bearings is to pull the drive shaft out and as long as it's out you should just replace them with a quality bearing (not Chinese made). My dad had a left drive bearing fail about 18 years ago and it caused the chain case to break. Based on the year of the sled and the mileage, I would replace them. You will need a bearing press to change the bearings.


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