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Discussion Starter #1
Anyone ever replace the tunnel in a Skidoo?  I am thinking of purchasing a new 136" tunnel from Specialty sleds, and replacing the old 121 DSA tunnel.  Just wondered what kind of a job it will be. If I decide to do this, I will install 136" M10, so I don't care about all the SC10 brackets. Seems like that is the best way to go. Any experience out there?
 

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If you really want to learn about how a sled is built, go for it! Might even find some things to improve upon, during the process. Or, you can just slap on an extension. Unless you're looking to strap on a hundred pounds onto the extension, you won't have any problem. They must be strong enough- doo has used a bunch of 'em.
 

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You pretty much have to dismantle the entire sled. Remove the drive shaft, jackshaft, chaincase, tub, steering hoop, seat, fuel tank, oil/coolant bottle and unbolt the trailing arms. Once you are that far you might as well remove the engine and everything attached to it.  Time consuming it is.  Mine on my Polaris took at least 24 hours, but I took a ton of time cleaning everything up.  The best way to remove the rivets is to just grind them off from the inside with a 4" angle grinder and drive out the rivets with a 1/8" punch. Personally I think it is a great way to go through your sled stem to stern to fix EVERYTHING that might be wrong.
 

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Discussion Starter #7
Well guys, I have thought about the extension, and it still may be an option, I just like the idea of a new .080" thk tunnel with no holes, and a natural finish.  I talked to Specialty Sleds about it, and they have both, but they said if I am going to install an M10 anyway, it would look better and be stronger to replace the 121" .060" thk tunnel with a 136" .080" thk tunnel.  It would also be nice to install bigger coolers as well. A tunnel extension kit is $250 from Bomb, and a new tunnel, with 136" coolers from Specialty is about $500 US. More work yes, more money yes.....but what will look and work better in the end?  Look better, be stronger, and cool better.  I have always had cooling issues with the 809/1025 when the trail gets a little soft.
 

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mach1025,
 i have replaced a tunnel on my kids sled once {380} no heat exchangers because it is a hair blower. the job was time consuming and nothing hard about it, i liked doing it because i could always come away seeing accomplishment.
 

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I say go for it!!  You'll be very satisfied when you are done. It will look really nice when you are done.  If you get started drop me a line..I have some great advice on rivets and tools you'll need.
 

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The kit from Doo includes rail extensions and some other junk. The tunnel extension is only about $50. I doubt your aftermarket .080 tunnel for $500 has rail extensions in the kit.


Not trying to steer ya out of installing a new tunnel, but am saying that the two routes are completely different. A new tunnel really means tearing your sled apart completely and rebuilding it. An extension is far less work.

I'm building a 144" out of a 136" frame. And I'm still going with the new tunnel route- ground up rebuild. And it's because I changed my mind about what track I wanted to use, after I bought and installed the tunnel.
I STILL have to rivet on a tunnel extension.

If cooling is an issue, maybe a rebuild is the better way to go- you can install new coolers. Great time to roll the case, if that's what ya want to do. More expensive, that's for sure. A recommendation made to me was to buy new brackets that mount on to the tunnel, if you are gonna go that route- the drop brackets, running board reenforcements, seat/tank brackets, etc. I'd suggest the same- get new ones. It's a lot of extra work to save them- cuz that's what I decided to do, against the advice.


When they install the tunnel at the factory, they use steel, self piercing rivets. I'm sure it's a pretty fancy jig. When they do that, those brackets get "tweaked". You'll end up having to hammer them flat where the rivets get popped through. And then you'll want to repaint them.

The easy route is to slap on an extension. The hard way is to rebuild your sled for that m-10 136". If you're going to install a  new tunnel, I'd have to give the same advise about rivets, though, use solid aluminum rivets. That advise, I did take.

Good luck.
 
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