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2010 800 RMK bogging above 7000 RPM?

W
I need some help with a 2010 800 RMK bogging(losing power) over 7000 RPM. It runs great till 7000 RPM. I rode it hard to 10,000 feet with no problems all day. We were dropping out at the end of the day and the last hill at 7500 feet it bogged climbing it. It bogged everytime I got on it till the trailer. The dealer mechanic checked everything he could think of and found nothing. No codes, clutches were good. Cylinder pressures were both 105 psi. Camera in jugs was one of the best cylinders and pistons he's seen with 800 miles on them. Pistons through exhaust ports looked good. Valves were clean. Fuel pressure and voltage held up at full throttle. Reeds looked good. Oil pump was right on. Plugs looked good. It ran great for him in the air at full throttle(no load of course).

I have an SLP can and a Power Commander 5 with Dyno Techs Stoughtner 157 map(LOVE IT). Clutches were balanced by SLP last spring. Exhaust valves plugged. I switched to my milder map that day(all negative values cut in half for more fuel on top end). I run 91 non ethanol with 1 gallon 111 octane race fuel added and 2-3 ounces of oil in the gas with 1/3 bottle of isoprople. Jumper is set for non ethanol.

Sorry for being so long but the more info, the better.
Thanks for any help,
Idaho Bill
 
W
Found Problem

I found the problem from the previous post this Saturday. One of the spark plugs was failing after several hours of hard riding. After failure, it ran great to 7000 rpm then would fail over 7000. I suspect a cracked insulator or the resistor was breaking down from the heat(2 feet of virgin powder). They were the Champion plugs with 800 miles on them from Polaris. The plugs looked clean when I inspected them so i did not change them on the first failure.

FYI

Idaho Bill
 
Last edited:

oldsno

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Dec 8, 2009
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I know you already looked at the exhaust valves make sure there is not a small tear or pin hole in one of the bellows we have lost a lot of those over the years I carry a spare they won't hold their r's on top end but will run fine other wise. worth a look I lost one on my 09 less than 500 mi.
 
W
Exhaust Valves

Thanks for the info. The bellows looked good. I did not do a pinhole check though. I do have my exhaust hose T filled with silicone to over ride the solenoid which helps with more pressure.

The new plugs ran great for 3 hours in deep powder hill climbing with lots of heat. My knees got very hot when we stopped if they got close to the SLP vents.

Idaho Bill
 
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