I have a 2002 Rancher ES 4x4. Owned many Honda ATV’s in the past and this one is a great machine I would recommend it to anyone. I purchased this new and for the first time service I had the dealer do the maintenance work. That was over a year ago and last week I changed the motor oil for the first time myself. The factory manual shows a small o-ring (about the size of a dime) on the inside of the filter assembly. When I removed the three blots to remove the filter I did see the large o-ring gasket that goes around the plate that acts as a seal, but did not see the smaller o-ring that was displayed in the owner’s manual. The filter has a rubber gasket on the inside that faces out from the motor and I don’t see the need for the small o-ring, but that’s not the point. Has anyone seen this o-ring in the diagram on their Ranchers when changing the oil filter? I put everything back together and no leaks, but I want to make sure that this will not affect oil pressure or something else negative. I not sure if this was left off on the first service by the dealer or is just a misprint in the owner’s manual. Please reply.

 

With the oil filter cover removed, there is a large o-ring that goes on the cover. There is a smaller o-ring (about the size of a dime) that fits in a recessed groove in the engine case on the right side facing the engine. This o-ring does not always fall out and if it is not leaking it is probably stil there.

I change the oil and filter every 500 miles. I also like to replace both o-rings and the aluminum drain plug gasket every time I change the oil and filter (only changed the oil & filter twice so far). They are cheep and I get like 6 of each at a time. I hate leaks. If you replace the drain plug gasket often, it makes its seal when it "squishes" and you do not have to tighten it as tight to make it seal. This lessens the chance of stripping the case trying to tighten it so it quits dripping.

Just y 2 cents worth.

 

I'll second what specta said. You can get by reusing the o-rings for awhile, but after a couple years they start getting flat and should be replaced. Best to have some spares around for comparison or in case they leak tho. Sometimes the small oring sticks to the cover when you pull it off, but the groove in the right engine cover for it is obvious. Also MAKE SURE you put the oil filter in the right way or serious engine damage will result. The drain plug washer should be replaced every time for exactly the reasons specta listed.