Loud 500 H.O.

[handyhiker]

I was just wondering if any one else that has a 500 H.O. engine thinks the noise is excessive. I have a 2002 Scrambler with the 500 H.O. engine. I have checked the valves and timing chain. The oil is never shiny from metal, but this is the loudest engine I have ever heard. It runs strong and is rock solid dependible, just very noisy. Is this normal for these engines??

I will try to describe the noise. It sounds like it is coming from mid point in the engine, not top end or crank areas. Almost like a rod knock but not really. Doesn't seem to get worse or better with oil change, hot engine, cold engine. Even when my buddy road it, he asked if it was going to be ok. I have owned this quad for about 2 years now, and the noise has gotten no worse from what I can tell. Should I be concerned about it?

I bought this quad from my brother-in-law. He only had it for a short time and did basicly nothing to it. I do know that before him, the quad was rolled/wrecked, not terrable but had some front end and steering damage. It does not use oil or antifreeze.

My one thought is that the piston may be cracked at the pin bore. This seems to be the area where the noise is coming from. Are these engines known for this or any other problems??

Sorry for the long post, just wanted to give enough info so you know as much as I can tell you about it. Any input would be greatly appreciated!

[Ajmboy]

I've seen some Polaris atvs that have a louder than normal engine. Some run smooth.

I would doublecheck to make sure that the engine is sitting in the frame properly and not causing a vibration. Also check that drivebelt. (I think it has one)

[handyhiker]

The engine is solid in the frame. It is at all rpm's. I have had the belt cover off and all is good there. Also it is not an exaust leak, I've checked that as well. ;-(

[handyhiker]

Well I got the answer to my question today. I stopped at a Polaris dealer on my way home from work and asked a guy in the service department about the noise. He said at first that he would have to hear the noise to tell what it was. I then asked if they had a 500 HO I could listen to to compair with. They had a Scrambler a few years older then mine, but the same engine. He fired it up and there it was, the same noise, maybe not quite as loud, but the same never the less. When I told him that was the sound, he smiled and said that that is the starter bendix. All the Polaris 4 strokes have that noise. He suggested I remove the pull start cover and clean and lube the starter drive and every so often make sure I pull the drain plug on the pull start housing.

So it turns out is is NOTHING to worry about and it really was coming from mid engine. He also said that the 500 HO are pretty much bullit proof. No issues that he knew of.

Now I feel better. Like I said, it runs strong and has been rock solid. Hope this helps some one else as well as me.

[outlander560]

r u gunna clean it any time soon see if that fixes the problem??

[handyhiker]

I took off the cover last night and checked the starter bendix. I don't see any way this could be making the noise. I did lube the bushings and put it all back together. The noise is still there and seems unaffected. I am just going to accept it for now since the other Scrambler made the same noise and the tech said it was normal. I may do some more investigation into it this winter with more disassembly of the engine and clutch. I am going to have to disassemble part of the cluth any how because I am replacing the swing arm bushings and the left one is behind the inside clutch cover. We will see what happens.

[outlander560]

i see u never scramblers r tuff s.o.bs so u should be fine..