1700 Miles on my Stock 2012 Pro-RMK 800 should I do a top end?

99slpss · Aug 21, 2014

Hey guys,

I have a Stock 2012 Pro RMK 800 with 1700 miles on it and not touched a thing besides regular maintenance and it has been solid. I am a little worried about it for this coming up season and was thinking of doing a top end this fall. I have never done a top end rebuild is this something that is pretty easy to do? Is there any specialty tools one would need? do you have to diamond hone the cylinders before installing the new pistons or just clean the cylinders really good? do the pistons or rings have to be put in a certain way? is it wise to put in new wrist pins and bearings?

Any more info or help would be great!! Or if there is any north metro Minnesota guys that would help for food and beer I could make that happen!!

wfieldin · Aug 21, 2014

There was a very cool picture slide show of an RK-Tek drop in kit installation on here awhile back, it will give you a pretty good idea of what is takes to do a top end. Maybe someone can dig up that link. Speaking from experience of waiting to long to do the top end and blowing the skirts through the cases, do pistons for sure, money well spent.

damx · Aug 21, 2014

I would do the top end. Get the cylinder checked out for cracks and proper size and Put stock 2014 piston and rings in it. And ride for 1500 ish miles and rebuild again,

rmscustom · Aug 21, 2014

damx said:
I would do the top end. Get the cylinder checked out for cracks and proper size and Put stock 2014 piston and rings in it. And ride for 1500 ish miles and rebuild again,

Good advice there.

OuraySledder · Aug 22, 2014

Is the '14 version of the piston any better than the previous ones? Do we have enough time on '14 pistons to say that there were a factory fix? Seems to me that the much lighter pistons offered by the aftermarket vendors for the same price as stock would be the better avenue.

My 1200 mile '13 will get RKT drop in's this fall if I don't just trade it for a '14.

granto · Aug 23, 2014

Id rebuild top end my 12 has around 2500 miles on it I'm going with the bikeman kit just cause its available locally for me. I would of done mine around the 2000 mark but I still had warranty left.

N.A84 · Aug 23, 2014

If i were you, i would check the engine first. 1700 miles is not that much, i have about 1900 miles (3000 km) and the engine is still in good shape. FYI, i dont have many stock miles on mine 2011..

rmscustom · Aug 23, 2014

N.A84 said:
If i were you, i would check the engine first. 1700 miles is not that much, i have about 1900 miles (3000 km) and the engine is still in good shape. FYI, i dont have many stock miles on mine 2011..

Just curious on how you know that? Tore down and measured/inspected?

N.A84 · Aug 23, 2014

rmscustom said:
Just curious on how you know that? Tore down and measured/inspected?

Yes, 30 miles ago it was on a full inspection. Got a new set of rings because of bad porting , got the porting and rings fixed and voila. My brothers 2011 had alot more miles then mine when he sold it, that one was also in good shape, in stock form that is. Dont know if the buyer has done anything with it tho, but i guess he would have heard something by now.

rmscustom · Aug 23, 2014

N.A84 said:
Yes, 30 miles ago it was on a full inspection. Got a new set of rings because of bad porting a dude did, got the porting and rings fixed and voila. My brothers 2011 had alot more miles then mine when he sold it, that one was also in good shape, in stock form that is. Dont know if the buyer has done anything with it tho, but i guess he would have heard something by now.

Seems rings are a big problem with or without a bad port job (or maybe PI's chamfer job isn't that good either). One thing for sure is problems are blown out of proportion on the interweb... What did your piston skirt to cylinder clearance measure at them miles?

fuledya · Aug 23, 2014

It's a total throw of the dice. I just put RK TEK drop in kit on my 2012 SBA, it has 4100 miles, pistons and cylinders looked very good!

fuledya · Aug 23, 2014

Pistons

fuledya · Aug 23, 2014

Another

fuledya · Aug 23, 2014

New pistons!

N.A84 · Aug 24, 2014

rmscustom said:
Seems rings are a big problem with or without a bad port job (or maybe PI's chamfer job isn't that good either). One thing for sure is problems are blown out of proportion on the interweb... What did your piston skirt to cylinder clearance measure at them miles?

Could be, but haven`t heard about so much problems with them either to be honest. Agreed, interweb is a to powerfull. I dont recall, it was done last year. Barely used the sled this season because of to much work.

OuraySledder · Aug 24, 2014

fuledya said:
It's a total throw of the dice. I just put RK TEK drop in kit on my 2012 SBA, it has 4100 miles, pistons and cylinders looked very good!

Not really... It is well known that the motors last a LOT longer in the trail sleds than the mtn sleds. They just do not see the extended wide open throttle time for the miles, nor do they accumulate the same number of engine hours for the miles. The better cooling in the SBA helps a lot too. Apples vs Oranges.

fuledya · Aug 24, 2014

Sled has at least 2500 off trail miles, and I would say its a far cry from a trail sled.

Sxrlar · Aug 24, 2014

Ive got a little over 2200 on my 2012, compression is still good, I pulled the valves, and looked at the rings and pistons, and did not see anything to alarm me. Under warranty until 2016, so, I guess I'll let er buck!

OuraySledder · Aug 24, 2014

fuledya said:
Sled has at least 2500 off trail miles, and I would say its a far cry from a trail sled.

Th quick math reveals 1600 trail miles... Long track SBA? How many hours? Off trail like this?

Just trying to get an accurate idea here because VERY few mtn ridden Pros have lived that long bone stock. Many trail ridden SBA's make that kind of milage. If you make 2000 miles on a stock Pro top end, you have done well, time for new pistons.

sledheadd · Aug 24, 2014

Mine has 1700 miles also 13 pro rmk I started experiencing a bog on long pulls so she's getting a MTNTK kit .

1700 Miles on my Stock 2012 Pro-RMK 800 should I do a top end?

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