2004 Rev Top End

[jscanga]

After reading and heading everyone's warning about the ring keepers in the '03 and 04 800 HO's I have a fresh set of wiseco performance pistons waiting to be installed. Being a rookie I was looking for any words from the wise on doing this rebuild. Any and all tips and tricks would be much appreciated.

Keep praying for snow while we can still afford fuel for the sleds!

 

[Backcountrypro]

Use the search function here or go to Dootalk.com and do a search on top end rebuilds....plenty of reading to do there.

 

[Blu Du]

it's not to bad you can do it. the wrist pin bearings are cageless so you need new caged bearings or get the tool that holds the bearing together. the circlips that hold the piston in are a real joy to put back in but it can be done. we did mine in the parking lot out in w yellow last winter. will save $400 on labor i'am geussing. need a torq ratchet and torq all bolts to spec. get all new gaskets

 

[hymark860]

Make sure you check the ring gap.

 

[JROD]

Try this one bro!

http://www.snowest.com/forum/showthread.php?t=98586

 

[Macattack]

Doesn't the wisco's required a slight hone to properly fit in the stock bore? I don't think the wisco's are simple drop in. But then again, I could be wrong. Double check tho!

 

[TruckerBallZach]

Definently hone your cylinders! your want a fresh, prefectly round/straight bore to start fresh pistons on. local dealer told me to torque the cylinders to 29 ftlbs and the head bolts to 21.

 

[jscanga]

I have read several threads some say to hone some say to use a scotch brite to clean the bore and just check for any signs of damage. The consensus seems to indicate that actual honing into the Nikasil is BAD--it seems that you want to break the glaze on the cylinder, thoroughly wash and call it good.

Also, the gasket kit doesn't call for any sealant-I have read some who just used WD-40, the manual calls for Loctite 518 on the base gasket. What have you done and what works/doesn't work?

Any tips for getting the piston pins out?

 

[Macattack]

The hone wasn't for seating the rings .... I think there is a clearance issue with Wiseco's in the stock bore.

No sealant on the base gasket, and you must get your hands on a piston pin puller.

 

[superduty187]

be very carefull removing the cageless bearings you do not want them falling in your crankcase also i was told not to use wiseco pistons for 800 rev oem is a better fit

 

[crashleroux]

Just a quick thought, while the stock oem pistons were not the best design, they have since changed the design on them. I still have an 04 800 that I was set to rebuild at 2000 miles, instead I lost the lower rod bearing that also cracked the case. For the price of a top end rebuild a crank fix and having the cases welded, I was able to get a complete shortblock for ~$1300.

Moral of all that, It is never a good idea to go aftermarket on Rotax engine parts they are one of the top engine manuf around the Austrians take great pride in their workmanship.
As for the honeing, it is always best to run a ball hone through a nikasil cylinder, as long as you don't overdue it. It takes the "glaze" off the cylinder and allows the new rings to seat better.

 

[JROD]

I've said this a million times but I'll say it again. IF YOU'RE GOING TO USE WISECOS, MAKE SURE TO WARM UP YOUR ENGINE PROPERLY and you'll never have a problem. Wiseco has fixed the freeporting issue with their pistons versus the oem set up. The double ring set up is an added feature too.

For those out there who think that you need to hone the cylinder to fit the wiseco, where did you hear or see this??? Nikasil is an extremely hard finish and you would have to spend hours honing and cleaning to get any kind of drastic change in cylinder diameter and even if you could, you would screw up the taper bore as well as the roundness of the cylinder. Sorry to go off, I just keep hearing this and it bothers me The ONLY purpose of a hone should be to break the glaze on the cylinder. I usually use ATF as a cutting oil and clean very well after honing.

Also if you plan on running nitrous allow about 20 thousandths ring gap on the bottom ring and 24 thousandths on the top.

 

[jscanga]

Thanks JRod--I am with you on the hone and the wiseco issues--I was obviously not scared away--Just looking for a little reassurance from the Pros (or peanut gallery).

 

[portgrinder]

most hones won't really touch nicasil.

 

[JROD]

Thanks JRod--I am with you on the hone and the wiseco issues--I was obviously not scared away--Just looking for a little reassurance from the Pros (or peanut gallery).

No problem. If ya need any torque specs for that, just let me know. I've got plenty of ski-doo manuals kicking around and I can give ya whatever ya need.

 

[bungeeguy]

I don't care what anyone says... the wiseco's are ****! Had one completely break the entire intake side of the skirt off within 400 miles, spun around the crank, broke my case, broke my cylinder, and damaged the head. I would love to beat the living crap out of a wiseco employee just to make myself feel better about their crappy product.
Get OEM pistons and use a 12mm socket and engine grease to hold the bearings in place while you slide the wrist pin through, works great!

High paying job offered to CEO of wiseco, please apply at the end of my fist!

 

[ak]

You should put loctite 518 sealant on the base gaskets.

 

[JROD]

I don't care what anyone says... the wiseco's are ****! Had one completely break the entire intake side of the skirt off within 400 miles, spun around the crank, broke my case, broke my cylinder, and damaged the head. I would love to beat the living crap out of a wiseco employee just to make myself feel better about their crappy product.
Get OEM pistons and use a 12mm socket and engine grease to hold the bearings in place while you slide the wrist pin through, works great!

High paying job offered to CEO of wiseco, please apply at the end of my fist!

And I had a race fuel doo triple mod 809 engine that I ran at 9600 RPM for two years and 1000s of miles. When I went to put in a new top end, it didn't even need it but I did it anyway. The Pistons looked brand new. Maybe it's because I run Klotz.

The fact that the 800 HO doesn't have the best intake side lubrication doesn't help but there's ways around that. Pull any stock 800 HO piston and there's scuffs on the intake side. Nature of the beast.

I know plenty of people that have had similar problems with just a few miles on oem pistons but of course, it's always the manufacturers problem, never the mechanic or the rider. Just saying that $hit happens and if hasn't yet, then it will. Point being, use whatever you want and learn from your own experiences.

 

[Slamnek]

Use OEM or RK tek. Much better fit than siezco pistons.