I'm rebuilding the motor on my 2001 XC 800. I need to find and good kit. Right now the only kit i've looked at is the wiseco performance kit that comes with all the gaskets too. Is this a decent kit or is there some better pistons. The motor is not blown up but has about 4000 miles on it and want to rebuild it. What else should I look at doing. I found some rods for $90 a piece. Also I am wondering about the kit from SLP to strengthen the crank. Any help would be appreciated. I would like to spend under $300 on the pistons and gaskets, if anything else is recommended I will do that to just want to keep the motor strong. I currently have CPI twin pipes on if that makes any defference in the pistons. Thanks.

I would get the crank checked by some one that knows polaris stuff. Motor base plate would also be a good idea, there is a guy on snowest that has a good piece at a fair price. If your over 4000' I would do a coin toss on the head , under 4000' I would get a custom head from RTK to reduce the compresion. The 2001 800 motor was very close to midrange det stock , I would say twin pipes will only make it that much closer. Also check your airbox most of the 2001 crack right at the oil tank , its not a big deal but sure does make a mess!

This is a short version of what to do if you are capable of doing the disassembly and assembly yourself.
Take the engine down completely while looking for problems.

Take the crank, case& bolts, cylinders to a reputable shop. They need to check the crank out completely (dissasembly and measurements), measure the case bore and measure the cylinders. Repair or replace as needed. They will tell you if you need new rods or not.

Order new cast pistons, I like stock or SPI, and gasket kit with all seals- again stock or better priced aftermarket like winderosa. The shop will measure the pistons and advise you on the clearance to bore.
A new WP belt and thermostat is often a wise thing to do right now. Also check for excessive wear on the oil pump drive.

After the engine is back together measure the crank runout and record for future reference. ( actually should check that first thing in case it needs to go back to the shop) You can check this as often as you like to keep an eye on any potential problems as you put the miles on it.

Obviously that is the basics, if I have forgotton something I'm sure someone will help out

If you are going with an after market piston kit like wiseco I have no complaints about them. Run them in my sled and they work fine. But I will say this, don't bother with their gaskit kit, I would still get the Polaris gaskit kit instead. I know it's more coin but at least the gaskits are to spec, imo.

I have a stock (clutched/geared/Tempaflo) '01 XC8, used strictly for trail, with 7600 miles on it. I topped it at 5000, just cuz (compression was fine), and used all Polaris parts (new factory pistons are coated). Didn't do anything with the crank. I'm shy of the Wiseco pistons. They are famous for seizing, but some say they've never had a problem. With the luck I've had with the factory pistons, I would have a difficult time thinking of a reason to switch.

Definately get SPI pistons, there a great quality piston and are cheap cheap(52 for piston, rings, circlips and wristpin), we've used a few sets in a few differant sleds and no problems. You can get them through www.hiperf.com in the engine parts section.

Don't let anyone who haven't used spi pistons tell you not to use them.

Be sure to change water pump belt and smear lithium grease on the top of it so it doesn't crack, check water pump bearings, get the crankcase baseplate like mentioned above, and have crank trued, keyed and big bearing installed if possible.

How about rod bearings, how often to replace them?
I replaced mine along with pistons at roughly 7000 miles last year.

Listen No matter what you do go with a bearing up grade on the pto side of the crank theese fail often at around 5000 miles of average use trust me I know first hand if you do this and put a stock polaris top end in it you will have a very solid motor for years to come

A lot of good advice has been listed above. The only thing I would like to add is check out your primary clutch, have it reworked with new rollers etc and have in balanced. Install new bushings in clutch weights or purchase new ones. Out of all the 800 broken cranks I have seen, most of the clutches that were on these motors the owners neglected the maintenance on the clutch and it cost them. Also check your pto front motor mount.

I HAVE AN 01 800 WITH TWIN PIPES MODDED HEAD AND POLISHED EXHAUST PORTS AND HAVE 14000 MILES WITH NO ISSUES WITH MOTOR OR CRANK, OUT OF CURIOUSITY I OPENED THE MOTOR UP AT 11000 MILES TO SEE WHAT IT LOOKED LIKE AND IT SEEMED FINE, BUT SINCE IT WAS APART I CHANGED PISTONS AND RINGS. GREAT SLED NO PROBLEMS AND FAST...I CALL IT THE VAMPIRE BECAUSE WHEN I GOT THE CLUTCHING JUST RIGHT IT WAS KIND OF WARM AROUND 25 F AND IT WAS A LITTLE RICH THEN ALL OF A SUDDEN IT DROPED ABOUT 20 DEGREES RIGHT AT DARK AND IT JUST RIPPED......HENCE THE VAMPIRE WAS BORN AND EVERYBODY JUST HATES IT BECAUSE IT IS SO OLD AND STILL RUNS LIKE IT DOES WITH NO PROBLEMS