Hey guys. I have a 98 Polaris Sportsman 500. I've been having performance issues for a while now…mostly bogging and recently what I want to say is some type of miss. A couple of days ago I decided I would adjust my valves. I know its supposed to be done every 100 hours or so and I'm afraid to even guess how many times im over that.

My valves were incredibly tight. I couldn't even fit a .002 feeler guage under either of the intake or exhaust valves, so going to .006 seemed really drastic.

Anyways me and the lady were gonna go riding down a dirt road right up from the house. About 3 miles into the ride, we heard a metal slapping sound. I stopped and shut her off. I looked over everything and proceeded to crank her back up only to find out she wouldn't start up. The motor also felt incredibly hot.

I got a tow back to the house and tore her down last night and my timing chain appears in tact and my flywheel key is fine but the flywheel will not turn past a certain point at all. Does anyone have any ideas?

 

Have you gone past the flywheel and pulled the stator plate to inspect the crank sprocket and key? I'd do that if you haven't already. If the slotted nut backed off the sprocket could move and shear the key. That would throw the cam timing off and possibly have a piston hit a valve. If the crank sprocket,slotted nut and key are ok,then sounds like the crank may be locking up on a piece of broken piston skirt. Flywheel magnets are enclose on this model..

 

10-4. So I backed out all 4 valves to .008 to see if shed crank just so i could actually get her to the back yard to my work area, which somehow they had tightened back down to below .002, and she fired right up again but I have to say the motor got very warm fast.

Now that I have it where I can actually work on it, I'll proceed to pull that dreaded flywheel and stator plate and check that out. As much as i hate pulling that dang flywheel with my mickey mouse 15$ puller from autozone lol. Preshiate he help OPT. ya never fail me

 

Valve clearances shouldn't be tightening up if they were adjusted correctly while at tdc. Possible you could have a couple bent ones. Engine getting warm could be from a stuck thermostat,air in the cooling system,or even a weak oil pump. Oil pump pressure should be around 20 psi with a minimum of 12 psi at an idle.

 

Think I found it. The wire to the thermostat broke off a while back and I soldered it back to what I had left on the thermostat and it apparently broke out/off again. I guess I did it when I was adjusting the valves. Time to try and resolder again lol.

 

On the 500 the sensor on the head(#2) is for the hot light only,the thermostat(#1) is separate and yes the light will come on if this sensor wire is broken. If once repaired and the light goes off,if it comes back on again while driving,bleed any trapped air from the system by leaving the radiator cap off while running, plus there is a small bleed bolt on the water pump cover that can help also.If the fan doesn't cycle on and off as it should that's usually the because the sensor at the top of the radiator has shorted out. These early models were bad on this when coolant level got below the sensor.You can check a thermostat by dropping it in hot water to see if it opens. If in doubt replace the thermostat.