Spent some time (a lot actually) tonight looking at pdf files for wiseco pistons for skidoo machines.
Specifically I was looking for any pistons over 82mm with 18mm or 20mm wristpins.
I am azzuming these are all two stroke pistons so keep this in mind and verify with wiseco.
Basically all the overbore pistons I found that might fit an oddy or pilot all had 20mm wristpins and none I found had the 18mm wristpin. Therefore the list below "MAY" only fit a pilot. The oddy has an 18mm wristpin.
Obviously I may be wildly off the mark here if the wristpin hole locations are different than a pilot so that's why you have to verify with wiseco.
I don't own a pilot so I have NO CLUE how much you can actually overbore or if it can even be done safely without splattering your Engine all over the dunes.
These are only skidoo pistons but maybe arctic cat or some other manufacture will fit.
Caution word here is VERIFY or take a gamble because you got nothing to lose or got money to experiment.

Here we go:
Skidoo: Pistons may fit Pilot overbores CW20 (20mm wrist pins)
Available sizes: 82 - 82.5 - 83mm
Models: Piston numbers: 2430M08200 -- 2430M08250 -- 2430M08300
793 EngineType
Grand Touring SE 800 2002-03
GSX Limited 2004-06
GTX Limited 2006
Legend GT SE 2004
Legend SE 2002-04
MXZ 800 2001
MXZ X 800 2001, 2003-06
MXZ Renegade 2003-06
MXZ Renegade X 2005-06
MXZ REV, RER 2003
MXZ X 800 2001, 2003-06
MZX Adrenaline 800 2001, 2003-06
Summit-Adrenaline 2003-04
Summit Adrenaline 144 2005-06
Summit Series 2001-05
Summit High Mark Series 2002-04
Summit Sport 2004
Summit X Series 2001-06

Overbore to 83mm --- Piston number 2392M08300
OVERBORE to 680cc for:
Powder Special 1998-00
Powder Special EFI 1998-99
ZR600 1998-99
ZR600 EFI 1998-99
ZL600 1998-99
ZL600 EFI 1998-99

Overbore to 86mm --- Piston number 2400M08600
OVERBORE to 790cc for:
Mountain Cat 700 1991-93
Mountain Cat 700 EFI 1991-96
Powder Special 700 1999-00
Wildcat 700 1991-96
ZL700 2000
ZR700 1994-96, 1999-00

Just for comparison the wiseco number for an 82mm pilot piston is 577M08200

Lets see if I can attach the pdf or if it is to big a file.

Pilot cylinders can be bored out to about 83.5mm but pistons beyond 82mm are not available. La sleeve can still supply new sleeves.

Skidoo uses single piston ring for less friction too. Less life probably.

I’ll keep this in mind. I still have another 81.5 and 82mm available over here.

Found one more.

Polaris:
Liberty motor (( Internal Combustion Engine ? ))
900 Fussion 2005-06
900 RMK 2005-06
900 Switchback 2005-06
Bore x stroke 83 x 80
STD - 2447M08300 866cc
1.00 - 2447M08400 887cc

Hmm I found this on eBay. Apparently someone started making 82.5-83.5mm pistons for FL400r?

https://www.ebay.com/i/123739927221?chn ... 4effeb630e

Comments please?

I just messaged the guy. Seems to be some old FL racer, but in a newer ebay profile. Here is the text description from the ebay listing (in case this guy disappears all of a sudden)

CW racing engines are making/selling these?

https://www.facebook.com/cw2stroke/