Snowmobile Forum banner
1 - 8 of 8 Posts

·
Leaves in belly pan, BAD!
Joined
·
330 Posts
Discussion Starter · #1 ·
I'm new to the brand and my education is starting. So far Ski-doo school has cost me $1000 for replacing pistons and rings.

It's not the first time this engine has been open. I'm looking for advice fuel/air mixture, maybe an improved liquid cooled head from a newer engine? Cooler plugs? I'm hoping to not have to do this second time.

We have first overbore Wiseco pistons and new rings in and it runs well now.

I'm wondering if anyone has been through this.
Tableware Drinkware Grey Waste container Gas


Drinkware Tin Cylinder Tableware Gas


White Blue Fixture Door Automotive tire


Automotive tire Wheel Finger Alloy wheel Rim
 

·
Administrator
Joined
·
19,276 Posts
Many times, a lean condition will cause the issues you have shown. A lot of the time, that is caused by a bad PTO crankcase seal. Make sure the seal is not leaking before riding it too much, or you will be doing it all over again.

Make sure to warm up the engine really well before riding. Wiseco forged pistons heat and expand at a different rate than the block, and can cold seize very easily When I had sleds with Wiseco's, I would start them, let them warm up for about 10 minutes, then shut them off to let the engine heat sync. And ride easy the first few miles...

To test the PTO seal, with the engine idling, spray some carb cleaner or WD40 on the seal behind the primary. If the engine RPM changes, the seal is leaking and you will need to replace it.
 

·
Registered
Joined
·
4,468 Posts
Cooler plugs won't do anything but carbon up more.

You didn't say which sled it was. The MXZ 500ss takes 360 mains in both carbs. You should verify that and might even go up to 370 on the side that is running lean. Suppose should make sure it has the TM-40 carbs too. I know that some people were swapping MK-40's instead of the TM-40s.
 
  • Like
Reactions: silversurfer

·
Leaves in belly pan, BAD!
Joined
·
330 Posts
Discussion Starter · #8 ·
Thinking of buying this head maybe.

The carb boots are an excellent idea, thanks.

Gas Auto part Tin Machine Metal
 
1 - 8 of 8 Posts
Top