RMK 900 top end rebuild questions!

[overkill131313]

I have a 2005 900 RMK that has 3000 miles. what is the best way to to the top end? what pistons should I use? never been into a 900...what kind of wrist pin bearing is used? hone the cylinder and just install new pistons and rings? can someone walk my throught this? what should my compression be? I know the crank....going to see how long I can get out of it since this is a great running 900 so far lol.

 

[T-BO]

Compression should be in the 120-130 range. If the compression is around 110 or lower I would change the pistons to the 06 updated polaris factory pistons and see if the cylinders need to be honed. Pistons come with rings allready. Wrist pin bearings should be fine to reuse but are sold seperatly.

 

[overkill131313]

is the wrist pin cage less or not? stock 06 pistons....whats the difference?

 

[T-BO]

They are caged. No need to worry about needles falling everywhere. In 06 they changed the 900 pistons and are supposed to be better. I guess?

 

[overkill131313]

thanks alot! any special tools needed?

 

[94fordguy]

Definitley get rid of those 05 pistons for the 06s ASAP.... The 05 are no longer available actually, they were very prone to dropping the skirts and taking out the rest of the motor with them. Polaris OEM 2006 pistons are the best pistons available for the 900 motor.

Luckily since it's an 05, the top end can be done in the sled, unlike the 06s. Another thing to have a look at while you are in there is to inspect the throttle body boots, if you see any cracks you need to replace them, but that;s getting a little off topic I guess.

Good Luck

 

[overkill131313]

why can you do a 05 but not a 06 in the sled? what is the difference?

 

[overkill131313]

and what parts do I need? 2 pistons/rings,gaskets????

 

[fnDan]

why can you do a 05 but not a 06 in the sled? what is the difference?

I heard that the extra injectors require pulling the motor.

 

[overkill131313]

ouch! that sucks just to do a top end. I guess one day I will have to figure out how to pull the 900 engine, but as for right now I just want to do a top end lol. any input would be great!

 

[High Velocity]

I just completed a complete overhaul on my '06 900 - pistons, 32 mm. crank kit and new case. The only thing I will add, is that the piston circlips on the 900 are a beotch. I've been a mechanic for 28 years and rebuilt countless sled engines and the clips in the 900 are the toughest I've ever dealt with. I ended up taking my crank/case assembly and new pistons to my dealer 80 km. away to use their c-clip installation tool after fighting with them at home for three hours. With the proper tool, it took me about five minutes to install both pistons. Ordered a c-clip tool for myself while I was there because I'm never going through that again.

 

[94fordguy]

I heard that the extra injectors require pulling the motor.

Correct. On the 05 the 2 injectors are down in the case only. The 06 has 4 injectors, 2 in the case and 2 for the cylinders and the fuel rail connects them together. There is no way to pull the fuel rail off without pulling the motor.

 

[overkill131313]

so what is the special tool needed for the circlips? do I need a wrist pin puller?

 

[High Velocity]

Shouldn't need a wrist pin puller. My wrist pins came out fairly easy with gentle taps with a brass drift. The c-clip tool isn't an absolute necessity as lots of guys have rebuilt 900's without it, but I refuse to fight that much with such a small item. Here's the tool I ordered from my dealer. You can't order directly off that SPX website. It's for Polaris dealers only.

 

[overkill131313]

so is the wrist pin 22 mm in diameter? another question is when I pull the head off, what is involved with the den. sensor? do I need to take it off or is there enough wire that I can just lay the head out of the way. do I just get the cylinder honed or do they need re-plating? is the 06 piston a double or single ring?

 

[[Freerider]-]

I'd hate to have to pull the engine on the 05, so much wiring everywhere haha. Our stater just went...took everything appart, luckily we were able to keep the engine in, and just wrestle with the wires and everything. Such a pain.

 

[overkill131313]

well I have about 300 miles on her in the last 3 days. going to hit it hard tomorrow. she pulls great and now that I set the TPS it has zero bog and starts better and idles and goes into reverse lol. the c-clips only took 5 mins on each piston with out the tool. you guys had me scared lol. going to see how many miles the original 05 crank will take lol knock on wood lol.

going to blue lake tomorrow!

 

[H2O]

Did you redo your cylinders (Nikasil coating)? Or did you only replace the pistons?
Also did you check your crank runout?
Happy riding!!

 

[overkill131313]

just changed pistons. cylinders were great. end gap on rings were .021-.022 .016 would have been nicer but I can live with .022 lol.

crank run out is same as last year .0025 and both rod bearings have zero dis coloration. they "LOOK" good but Im going to drive it like I stold it.... like I have for the last 3000 miles and see what happens. old pistons look perfect and compression was 135 but I just want to get those 05 pistons out since guys say they break the skirts off. I really didnt see a problem but want a touble free year lol.

she pulls hard! told the father in law that my rings havent seated yet because Im still adding oil to my tank lol I think they have seated now and I have 400 miles. going to do a compression test tomorrow and see how it looks. the biggest improvement was setting up my TPS.....zero bog now and starts great lol. thanks for all the info and help guys!

 

[overkill131313]

150 psi after 600 miles. pulls hard! but now its for sale......I need the money!