Hello,

I have had my 99 Xplorer 300 for about 10 months now. It runs great and starts instantly, but since I have had it, it has always been loud.
Now, I figured it was the exhaust that was loud, and it really didn't bother me that much so I hadnt done anything about it until a couple weeks ago.
I pulled of the manifold, gasket looked pretty good, but I cleaned off the surfaces well, put some hi temp RTV around both sides and bolted it back down just to be sure. I pulled off the rest of the front exhaust pieces also just to check them, no holes, I cleaned up the mating surfaces there also and put some RTV on the ball side of the ball/socket type connections. All of the springs are still holding tight.
This leads me to my question. I am thinking it is the motor itself that is loud. A compression check showed me ~ 105 PSI which seems kind of low to me. The engine does vibrate significantly and smooths out once I give it just a little gas. My question is, could low compression cause the engine itself to be louder than normal? My friends 94 400 sport is quiet and my girlfriends 04 TB330 is dead quiet, so mine being loud is out of place [img]i/expressions/face-icon-small-smile.gif[/img]
The motor mounts seem in good shape, as they do not have much give when I push on the motor.
Is there anything else that could cause this? I am not afraid to tear the cylinder out and put a wiseco in if needed, it doesnt seem like it would be too difficult to do.

So if anyone has any ideas, lemme know [img]i/expressions/face-icon-small-smile.gif[/img]

Thanks,
-Chris

 

Anybody? [img]i/expressions/face-icon-small-smile.gif[/img]
Somebody has to have an idea around here... I would hope [img]i/expressions/face-icon-small-wink.gif[/img]

-Chris

 

It's louder than the 400 because it's air cooled, but it shouldn't be that loud. My 250 TrailBoss wasn't that much louder than my Sport or my Xplorer (I had the TB and the Sport at the same time)

 

Yes, it is significantly louder than the other 2, especially when wide open. I still can find no exhaust leaks, I havent been around any other aircooled polaris' to compare really, maybe it is normal, it just seems pretty loud.

-Chris

 

there is an air screw on the side of the carb,the more you screw it out,the more "detonation" noise it will do cauze there is more air than gas,chech it out,screw it in,,,it should help.

 

I believe I had already checked the air screw.
I looked up the spec and it said 1.5 turns out, which is where I have it set to. However, there seem to be 2 or 3 more adjustable screws that I didn't touch. Any idea on placement of the screw you are referring to? just general location.

Thanks,
-Chris

 

I think it just the nature of the beast, I used to ride with a 300 explorer and no question it's louder than a 400.

 

the water in the cyclinder dampens the sound more than an aircooled engine

 

That's what I was wondering. Maybe it is normal, It's just the only polaris 300 I have heard [img]i/expressions/face-icon-small-wink.gif[/img]

Now about the compression thing, would 105 PSI be a good point in which to throw a wiseco in at? as in, would that low of compression hurt power enough to be real noticeable?

-Chris

 

what is the carb on the 300?
an air screw will help to keep noise down a little,but a fuel screw
will do nothing to it at all.
but from what i heard and seen those 250 and 300 2 stroke, make a lot of frenquency noise all coming over the head and cylinder,
it have to do with piston port engine.