14 Pro RMK Bog Over 6000 RPM

[WGMT802]

Hello All,

I have a 2014 Polaris Pro RMK 800 stage 2 SLP with 2800 miles. Last year this sled developed a nasty bog over 6000 RPM. I tried every type of fuel and fuel mixtures from 93 non ethanol to 100 with octane booster and it didn't change. This summer I removed and replaced the reeds. New fuel filter. New spark plugs and wires. New exhaust valves (guillotines, bellows, spring, ect.). Clutch has been completely cleaned, reweighted and new springs to what SLP says for my elevation, 6000 ft. New injectors. Rebuilt the crank and the top and and re nikasiled the cylinders. Engine has all new seals and no leaks. starts up 2nd pull every time when cold and 1 pull when warm. Runs strong from 1600 to 6000 and then bogs down and stutters and cannot get over 7200. When the throttle is pinned the sled surges from around 6200 to 7000 rpm. No CEL lights. This years I've now done 50 miles on it and it still has the same bog. I've been thinking about have the TPS adjusted or replaced but from what I've heard that never really fixes the problem. Has anyone seen this type of problem or have any suggestions?

 

[briand]

I'm not sure if you have the cable style or the exhaust gas style exhaust valve opener but this is for the exhaust gas style openers.
you could have a bad solenoid vale control for the guillotines. Check to see if the Exhaust valve are actually opening up as you rev up engine. You can check this by putting a short length of drinking straw through the plastic cover on the guillotines, onto the guillotines shaft and as the engine revs past 6800 or so you should see the straw move out on the covers. This is how i check mine. If it doesnt move out unplug the hose that goes to the cover and the exhaust valve solenoid at the solenoid and plug the hose and rev it up again. The valve should open and this should confirm that you have a bad solenoid valve.

 

[WGMT802]

Yes I do have the exhaust gas style. I did the and straw trick and saw it didn't go up. Plugged the line and found the exhaust vale did start to rise but still only rev'd to 6800. Removed and bench tested to solenoid. The solenoid works properly, it is normally closed and with 12 it opens. Checked the wiring going to the solenoid and found it is supplying 12v. Removed the exhaust valves again and verified all ports were clear, and the bellows are good.

I have just set up an appointment with Polaris to have them reset my tps and reflash my ecm.

 

[briand]

Something else you can check is, and maybe you already have, is the hoses that go to the exhaust valve to the solenoid to make sure there's no cracks that cause leakage in them. Seems odd that they only open a little when hose is plugged. Its just something quick you can.
I don't know if you had already knew about this and if you have just disregard it but Here's a little video about cleaning the exhaust valves and this is something that i had missed with these tiny holes behind the diaphragm that needed to be cleaned.

 

[Alpine Xtreme Edge]

Yes I do have the exhaust gas style. I did the and straw trick and saw it didn't go up. Plugged the line and found the exhaust vale did start to rise but still only rev'd to 6800. Removed and bench tested to solenoid. The solenoid works properly, it is normally closed and with 12 it opens. Checked the wiring going to the solenoid and found it is supplying 12v. Removed the exhaust valves again and verified all ports were clear, and the bellows are good.

I have just set up an appointment with Polaris to have them reset my tps and reflash my ecm.

I know you said you removed exhaust valves and checked all ports were clear...but just out of curiosity, did you confirm the small hole in the cylinder above and slightly right of center of each powervalve is clean and clear. That hole starts off big (1/4" ish) as your looking into it, but slims down very small pinhole like as is physically passes into the cylinder. I've seen sleds have similar issues to yours from one or both of these pinholes being plugged with carbon and 2 stroke oil sludge.

 

[Falcon1772]

Any resolution to this? I have a similar issue with a 2018 Summit 850

 

[WGMT802]

So I was able to find the resolution to this problem. It ended up being that the sled was over fueling at higher RPM's. Even with an ecm flash, tps reset, new injectors, new fuel filter and all aftermarket fuel controllers unhooked (so it was completely stock). It was still had that problem. We found it would run better when the engine got above 135 degrees because of the more heat in the engine it could burn off the excess fuel. I ended up filling the sled with 91 ethanol and ran it on the non ethanol setting (which is about a 4% fuel lean) and the sled ran great. Because I had an aftermarket fuel controller I was able to 2% lean over the whole fuel map and the sled ran great from there on out!

 

[silveradokokanee]

How did you figure out you were over fueling? Mine is having similar problems as yours.