# Rebuilding an MXZ today..



## Crazy Axe (Mar 11, 2007)

Man I have the biggest hard on for this project :lol::yikes:
Going with SPI pistons, new carb boots, gasket kit. Got the shop manual and we're going to pressurize the engine before we fire it up to make sure there are any bad seals so we don't eat the new pistons. Then hopefully we'll make a trip up north for some break-in time. If not we will be riding out at Richfield park I think. I've never ridden out there so it might be a learning experience...

Anyway, I'm sooooo stoked I just had to tell someone even if none of you guys care the least bit :evilsmile:coolgleam


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## Greenbush future (Sep 8, 2005)

I rebuilt one of them things but because the sled was dated, I sold it and went etec. First rip was last weekend, and I wasn't disappointed, need some studs to stop, but what a nice upgrade. No more carbs for me! 
Hope the build goes well, sounds like you have a strong plan!


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## limige (Sep 2, 2005)

Sounds like you choose your components well. They say to add some extra oil into your gas tank for the first tank for break in. Don't run it too hard for the first 100 miles.


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## SalmonBum (Feb 28, 2001)

And grease the pto bearing with isoflex and a new seal

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## Crazy Axe (Mar 11, 2007)

I didn't take the case apart just the top end. We ran into a snag while trying to torque the cylinders to case i broke a bolt. It didn't shear and it all came out but now we are having a hard time tracking down another and probably have to order it. I did a lot of research and compared cost effectiveness of components and quality/reliability and that's how i came up with those parts.

So maybe one of you more experienced guys can help me figure out why that bolt broke? I had the cylinders just barely finger snug and then installed the y pipe before trying to torque the cylinder bolts. I think my mistake was either too much on the cylinder bolts before installing the y pipe or i should have stepped the torque up like all to 10 ft lbs then all to 21, spec. Why else would it break like that?


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## SalmonBum (Feb 28, 2001)

Ski Doo uses bearings that use isoflex. They need to be repacked every 3000 miles, at least the pto side. If you don't your on borrowed time and a crank failure may be in the near future. No need to split the case, just need to pull the seal. Depending on if there is a retainer, could be easy or hard.

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## Crazy Axe (Mar 11, 2007)

So we are going to replace all four bolts on the mag cylinder because they are stretching.

As for greasing the bearing, it looks like there is some sort of retaining pin


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## Crazy Axe (Mar 11, 2007)

Oh and it says on the parts list to use Petamo ghy 133n, which is another kluber grease.. I assume it's comparable to isoflex? How come they didn't just run oil injection lines to the bearings? That's how my Polaris is set up...


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## SalmonBum (Feb 28, 2001)

Crazy Axe said:


> Oh and it says on the parts list to use Petamo ghy 133n, which is another kluber grease.. I assume it's comparable to isoflex? How come they didn't just run oil injection lines to the bearings? That's how my Polaris is set up...


That is just the way ski Doo does it. You can send the case to seadooclinic and have them mod it to be like your poo.

Fyi..... the poo's are known for bearing failures due to small bearings. Line boring the case for a bigger bearing is normal 

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## Crazy Axe (Mar 11, 2007)

I read that the 800 is known for bearing and crank failures but not so much the 700?


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## Crazy Axe (Mar 11, 2007)

Got it put back together FINALLY. Jeeeeesusss!
Getting ready to leak test it here in a few minutes. The plugs I made for the carb sockets are a little snug so I brought them inside to warm up and get a little more pliable lol
Hopefully I'm going to get it fired up tonight but I'm not going to count on it.


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## Crazy Axe (Mar 11, 2007)

First heat cycle completed. Going to fire it back up in the morning... Good god this sled sounds badddd assss! I don't remember it having such a deep rumble to it but then again I haven't heard it in probably 2 years. Kinda wish my Polaris sounded like that hahaha


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## limige (Sep 2, 2005)

Congrats. Feels good don't it!


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## Crazy Axe (Mar 11, 2007)

Hell yeah!

But... I went to start it this morning and it was running funny. Look down and the PTO carb is spewing fuel out the bowl vent. I'm going to dig into it in a couple minutes. I figure bad floats or stuck inlet needle or both? The mag side was sticking closed when I had it apart but I cleaned and cleaned and cleaned and finally got it to free up. I'm going to replace the inlet needles just for peace of mind!


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## Shiawassee_Kid (Nov 28, 2000)

Crazy Axe said:


> Hell yeah!
> 
> But... I went to start it this morning and it was running funny. Look down and the PTO carb is spewing fuel out the bowl vent. I'm going to dig into it in a couple minutes. I figure bad floats or stuck inlet needle or both? The mag side was sticking closed when I had it apart but I cleaned and cleaned and cleaned and finally got it to free up. I'm going to replace the inlet needles just for peace of mind!


new top end and you didnt bother to clean the carbs? do you even know the reason for the original failure?

if your gonna rebuild and go thru the trouble of leak down test...please take 10 minutes to make sure your carbs are clean...would be one expensive rebuild if you lean burn a brand new set of spi's.


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## Crazy Axe (Mar 11, 2007)

I cleaned the carbs before it was even taken apart but i didn't check the inlet needles then. I did go back and check them both and we are replacing one. I'm 99% certain the burn down was caused by old fuel/cold temps, possibly road salt build up on the clutch causing excessive heat. I'm going to keep a close eye in it when he starts riding it, pulling the plugs often but i don't think were going to have a problem. Clean carbs, fresh fuel, leak test looked good, it idles nice. I'm not worried about it failing but i do understand that its possible.


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## Crazy Axe (Mar 11, 2007)

Btw the one needle that us cracked, i assume from sitting for a couple years with no fuel in it, i replaced with a new one. The new one was sticking closed and starving that carb of fuel. That could have burned it down if i tried to ride it but i know better and quickly figured the problem out.


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