Seized 2013 Pro 800 RK TEK

[Sickbuild]

Hmm goes over 2000 miles, does a top end then goes 400 if I'm reading it right? Then a the cap decided to shat the bed?

Um not likely! Possible yes but slim.....


Ps.please, please, and please post another post about your k - mod 37inch front end.trying to make an informed decision.

 

[BILTIT]

Its not as simple as the cap fails or not fails, they can get full of belt dust/oil and plug up at anytime.

He would have to do some serious testing to be sure his cap IS/IS NOT working or just vent it for next to nothing and KNOW it is venting.

 

[boondocker97]

Are those the original jugs? Could be pic but something looks funny around the exh. port.

Something else to check (from a phone conversation) have a look for a vertical crack in the back boost port.

I'm kinda thinking along the same lines. Plating looks odd to me between the exhaust port and the bottom right transfer port in the third picture. Maybe it started flaking off?? If it was too tight in the bore I would have expected to see more damage on the left side of the piston too.

 

[revrider07]

What kind of prep work was done on the jugs prior to piston assembly and clearance measurements. Did sled run strong then seem to be going away each ride from rebuild? The 13s have a lean spot in the mid range and thinking these Pistons might make it worse. Stock head?

 

[dttrusko]

Sooo the stock engine is junk, but when you put in aftermarket parts and it goes down in 400 miles it's more or less a freak accident ?

I have done 5 top ends and 3 complete rebuilds on these 800s (11s and 12s) with all OEM parts and they seem to go around 4000 off-trail miles on a crank and about 2000 miles on a top end before needing to be freshened up (not looking like those pistons)... It also seems to me that the QC on the OE pistons have gotten a lot better in the last couple of years when measuring them in the quality lab at work.

IMHO, stick with OEM parts or if you really feel the need to go aftermarket, get a monoblock from indydan that you know is in spec. I haven't seen an injector failure do this. Usually the EGT sensor will let you know something is wrong if it is going lean and it still likely will not remove the oil film from the cylinder wall unless it detonates, which there is no sign of. An injector is usually blocked or fails to the point where there will not be a combustion event. I could be wrong, but it is an easy thing to trouble shoot.

 

[shortstuff]

Ok so I have a 2013 pro that had 1300 and some miles on it. I put a set of rktec pistons in it at the start of the year. I set the ring gap at 20 thousandths, turned the oil pump up three turns it was burning right around 45 to 1. Dumped almost a quart of castrol oil in the first tank. I rode the sled four times this year. Sled was running great I was very happy with it. On the fourth ride my crank broke off flush with motor. So in tearing it down to fix crank I got to look at my pistons and this I'd what I found. What do you guys think?

 

[turbo800]

If the Poo is anything like the Doo, they are quite lean in the mid-range. It's possible you might have had light detonation trying to attack the ring pin also. Couple the 2 together and you might have enough extra heat to swell the pistons into a seizure. It doesn't look like a cold seizure to me...

 

[SHAWNBRO]

Thanks for all the input, still trying to gather up parts to put it back together. Oil cap is not plugged, can blow air through while shaking cap. Im leaning towards it not being a fuel or oil problem. Thinking either nikasil flaked by exhaust port, cold seize or some combination. Lesson learned, if you want to ride a Polaris, buy the extended warranty.

 

[rmscustom]

I've got 1400 miles on them crap pistons and it still rips.

 

[mtncat1]

Ok so I have a 2013 pro that had 1300 and some miles on it. I put a set of rktec pistons in it at the start of the year. I set the ring gap at 20 thousandths, turned the oil pump up three turns it was burning right around 45 to 1. Dumped almost a quart of castrol oil in the first tank. I rode the sled four times this year. Sled was running great I was very happy with it. On the fourth ride my crank broke off flush with motor. So in tearing it down to fix crank I got to look at my pistons and this I'd what I found. What do you guys think?

they don't look to bad. how did you hone it? the finish on the cylinder wall looks really rough . you may want to rehone with a ridged diamond hone. then rering it.

 

[Snowmow]

I've got 1400 miles on them crap pistons and it still rips.

My sled has 1100 miles ALL boosted on mine...... Runs great.

 

[Snowmow]

1000 of those miles were with stock oil cap, no pre mixing oil in fuel, I think Carls turned the pump up...?? It's working!!

 

[dttrusko]

Just as a disclosure, I wasn't implying that there is anything wrong with RKTechs pistons or pistons that anybody else sells.. I just find it amusing reading some of these threads that bash the OE stuff and rave about having 1000 miles on anything other than OEM when there are 10x the amount of people who don't have problems with their engine/don't have an issue throwing in a set of pistons every 100 hours.. Call me stupid, but I like to think the OEM guys are also interested in making their parts last..

 

[shortstuff]

they don't look to bad. how did you hone it? the finish on the cylinder wall looks really rough . you may want to rehone with a ridged diamond hone. then rering it.

Ya I didn't know we used the wrong hone till after we had it together and rode it couple times. I'm getting it diamond honed right now. I was just a little worried about the mag side piston looked a little rough didn't want to put it back together if it was going to stick.

 

[boondocker97]

Ya I didn't know we used the wrong hone till after we had it together and rode it couple times. I'm getting it diamond honed right now. I was just a little worried about the mag side piston looked a little rough didn't want to put it back together if it was going to stick.

I was thinking that it didn't look like there was very much cross-hatch. Too much hone spinning and not enough travel through the bore when doing it. Should be about a 30 degree cross-hatch when done.

If you are having them re-honed I think I would at least put new rings in to re-establish the seal.