Howdy fellas. First post!

Little background; I've had a few quads over the years, blasters, banshees, a kfx 700, Suzuki 80's and now I have a YXZ 1000r. The majority of my quads were 2 strokes and I have built several banshees from the ground up, literally and ported a few banshee cylinders. My fastest bike to date was a 521cc power valve banshee.

So. Here I am. 2 days ago I purchased a 1995 sportsman 400 4x4 for my son. It was previously owned by an old man whose garage it sat in for 8 years before I bought it.

It's still all stock and now that I rebuilt the carb it runs perfectly.

I've been wanting one of these Polaris 400's to play with, and I'm pretty excited. My only concern at the moment is the piston. I heard that 75% of failures are due to Pistons breaking.

So, my plan is to bore it and install a wiseco piston. And while its down maybe perform a couple of cheap mods; I don't want to put much money into a quad I spent $900 on, lol.


So tell me how this sounds:
- wiseco piston
- mill head .035"
- raise exhaust port by 1mm or so and widen 2-3mm
-new reeds and open up reed cage a bit with a dremel
-new primary clutch spring to increase engagement and shift out rpm (spring recommendation requested)

How does this sound?

 

Doesn't sound too drastic,but also replace the cranks seals. After setting for 8 years with gas in the crank case as many do,the seals are probably junk. One thing that a lot of people forget also is to bleed the 10mm bolt on the head before you start it to remove any air pockets from the coolant. If you don't this engine can overheat quickly and warp heads,seize up brand new top ends.

 

Thank you

 

If you want to do anything else to it to boost your horsepower check out AAEN Performance for ideas. Aaen Performance - Polaris ATV Two Stroke - Top End Pipes

 

They don't appear to make top end pipes for a '95 sportsman

 

Does anybody k ow if the scrambler pipe will fit a sportsman?

 

They're different frames so I doubt the mounts would be the same.