Wow, I open it up, everything looks great! Really thought would have been able to see something obviously broke or cracked.

 

Hope you haven't got around to ordering all the parts you said you were going to.. Use this to check out the piston to cylinder clearance along with ring end gap plus will help track down what's wrong rather than going at something blind.2002 Polaris Sportsman 500 Service Manual PDF Download

 

no I haven't ordered any thing yet, thought i open it up first. I have a Clymer manual I will check both clearance and ring gap tomorrow. do you know what 2-3 stages means? " loosen the bolts in 2-3 stages then remove them"

 

i get it 2 to 3 stages DUH!!

 

Pay close attention to head bolt torque as the stages allow for good compression of head and base gasket along with allowing for head bolt stretch.

8. Tighten the four larger bolts (Figure 81) in a
crossing pattern evenly in the following steps. Mark
a line on the large bolts (Figure 82) for a degree reference:
a. Tighten to 30 Nom (22 ft.-lb.).
b. Tighten to 70 Nom (51 It .-lb.).
c. Loosen each of the four bolts exactly 180'
( 1/2 tum).
d. Loosen each of the four bolts again exactly
180' ( 1/2 tum) .
e. Tighten to 15 Nom ( 11 ft.-lb.).
f. Tighten each of the four bolts exactly 90' (1/4
tum).
g. Finally, tighten each of the four bolts exactly
90' (1/4 turn) more.
9. Tighten the two small 6 rnrn bolts (8, Figure 79)
to 8 Nom(71 in. lb.).

 

Well with further examination the piston is cracked between the rings, i noticed a color difference,moved the rings and a piece broke off, I"ll measure cylinder block tomorrow.

 

thanks!

 

That could do it... Keep us updated

 

checked the bore 92.00, has any one herd of Top Noch Parts? their on Amzon seems their parts are cheaper than Polaris OEM parts.

 

Many times you get what you pay for especially in no name parts. Some posters have used Namura,but the best piston out there is a forged Wiseco. Here's some of both if the cylinder can get by with a stand piston kit.1999 Polaris SPORTSMAN 335 (A99CH33CB) Carburetor | Cycle Parts Warehouse