I was out riding my sportsman 500 tonight and is has been running great after new rebuild. I was heading down a steep incline for a few seconds with both front and rear brakes on then the quad just quit. I thought I ran out of gas. But, I can not get the thing to fire back up. It had gas in it. It wont even run with starting fluid. I have spark. Timing chain is still tight, cam is spinning, just doesn't make sense. Any thoughts??

 

There's two bolts on the right side of the crank case. Usually allen socket. Take those out and remove the valve cover. The bigger hole of those two has another bolt underneath- this is to rotate the crankshaft. The other shows where the piston is in it's travel via two marks- one saying "F" for fire, the other saying "T" for top dead center. Rotate the crank until you see the "T" and it lines up with the mark on that hole. The camshaft gear has two lines directly opposite of each other. They should line up with the edge of the head (as close as they can). If they don't, you will need to remove that gear and reposition the chain on it until they do (with the piston at TDC). The only other thing to keep in mind is that if you take the gear off on the compression stroke, put it back on on the compression stroke. You'll know by some kind of mark on the gear.


Now, before you do all that, have you checked to make sure you're getting adequate fuel?

 

Just remove the recoil housing and remove the flywheel nut. If the woodruff key has split and the flywheel has moved on the crank shaft you will see it. This has happened to me a couple times only on the 500 engine. Plus the lower cam sprocket can do the same thing if the slotted nut backs off,can break the woodruff key,jump a little out time but still turn. OPT