Need help

[Danstoys]

Picked up a 2012 800 rmk pro. It seemed to work good at first but I noticed it wasn’t burning much injection oil. I did some research and seen you could turn up injection
pump, I was going for a ride that day so I just put some oil in the tank. The next day I turned up oil pump drained gas put in fresh stuff. I taught sled was running a bit lean because det light came on a couple times the day before so I decided to switch fuel resonator to entnol setting with premium fuel. So stared sled and while warming up check engine light came on. I figure maybe something to do with fuel resonator so I changed it back to premium but light remained on. I figured out how to get trouble codes and it said 542007-3 high voltage I think so I ordered a new resonator switched it out and light is still on. Took sled for a ride and it has a bog on the top end, about 2/3 into throttle it bogs. So I’m kind of lost at this point wounding if anyone could give me some advice. Thanks

 

[Danstoys]

Well brought sled to dealership because I figured it was electrical, turns out my crank is gone out. So I plan on pulling motor sending to iantommsi and getting a full rebuild, welded crank new bearings pistons head work and porting. Hopefully it will work good after that and be reliable. If anyone did this can you let me know how the out come was. Thanks

 

[JMCX]

I'm not sure why a failing crank would cause a high voltage code? Turning up the oil pump is a good idea. Adding oil to the gas tank doesn't help the crank bearings as the fuel injectors spray into the rear cylinder port as the air is on its way to the combustion chamber.

These things have fuel filters. Maybe yours is dirty causing the high rpm issues.

 

[Teth-Air]

See if you can get 2015 cylinders and pistons as they were improved. Also mapping was improved through the years. Might be good to see if you can find a complete 2015 parts motor to start with? When turning up the oiler be careful not to over-tighten as you will bend the linkage. Best to hold the linkage with pliers while tightening the lock nut.

 

[ABMax24]

I'm not really sure how they'd diagnose a bad crank out of that. But I'd also agree that replacing the fuel filter is the best place to start for the high rpm bogging. As for your trouble code chase the wiring from that fuel resistor back, my guess is it has rubbed through somewhere causing a short to power and the high voltage code. Turning up the oil pump is never a bad idea either.

IMO I highly suggest you reconsider your choice of engine mods. IMO there is no reason to weld the cranks on these motors, they stay extremely straight. I've never had any issues with straightness or having the crank throws go out of phase, and I've detonated my motor extremely hard while on boost (hard enough to blow the ceramics and core out of the spark plug). Most places won't take a welded crank back as a core, same thing goes for ported cylinders, so you are out a lot more money on the next rebuild.

 

[ABMax24]

See if you can get 2015 cylinders and pistons as they were improved. Also mapping was improved through the years. Might be good to see if you can find a complete 2015 parts motor to start with?.

That engine change partly occurred in 2013. For 2013 they thickened the cylinder skirt on the intake side to limit cracking and breakage. So any cylinder 2013 or newer would be an improvement. The pistons were revised for 2015 again though. But honestly I think the Polaris pistons are overpriced for what you get, I've ran both Wiseco and Pro-X pistons with better results than the factory Polaris ones and they are about half the price (granted I never did run the '15 pistons), the Pro-X ones even come with new wrist pin bearings.

 

[Danstoys]

Thanks for info I have sled back going to do more investigating tomorrow before I make any decisions. I will measure pistons to check crank.

 

[Danstoys]

Measured crank one piston on bottom other at tdc seems good, did compression test pro side 70 mag side 120. So I will start there and pull head. Thanks.

 

[JMCX]

It seems that you took out a piston. You will want to determine why that happened so not to junk another. Hopefully no debris went through the bottom end. I'm not sure what you're measuring on the crank. How many km on this sled?

 

[Danstoys]

Just marking piston tdc on one piston and the putting the other one a bottom and then making sure other piston still on tdc mark If crank went out mark will or should be off. Got head off looks like pto piston has wear on intake side I can see rings but not very much, I’m used to seeing holes in pistons lol. Sled has 5100 km.