390XP air box mod?

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Matt93eg

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I was scanning the classifieds and ran across this 395XP. It has holes drilled in the filter cover to get more air into the filter area. Has anyone done this and noticed a difference? My 390XP being a high top I could do this if it makes a positive difference. I was just wondering. Picture below of the 395 I saw.

On sport ATVs it’s common for guys to drill holes in the air box lids to help get more air in.

My 390 already has a muffler mod, other wise it’s stock. Just wondering what any experiences may be. Don’t want to drill holes in my cover if it doesn’t make a positive difference.
 

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That’s a ported saw and probably not intended for regular duty abuse. A stock 390 should get enough air with the cover intact. You can test it easily by running it with cover off and seeing if you get more performance. I doubt you will.

If you want more air getting to fhe Filter, check out Frogskinz. They’re mesh stickers designed for air box mods on snow machines and ATVs. They let air though, but keep debris out.
 
Good point on saw being ported. I got so wrapped up looking at the filter cover I didn’t pay any attention to the stickers on the saw.
 
Not to mention how clean the filter stays. Drilling holes you’ll be cleaning the filter more, also ill advised for keeping rain out of the air box when the saw is in the back of the truck.

There are enough reasons not to do it
 
Test with a tach and take off filter cover to see if the Rpm increase or not. See if its acting as a restriction. I suspect it isn't. Unless the air injection is sucking up fines from the front of the saw and clogging the filter, that's the only reason I'd drill holes in the rear. I'm not a big fan of air injection, I've plugged a few on my saws.
 
ahhh looked closer. thats a hotsaws101 saw. he would be just the type for a stupid gimmick like drilling holes in the af cover, just like the sticker that says “for competition use only”. :laugh:
 
That’s a ported saw and probably not intended for regular duty abuse. A stock 390 should get enough air with the cover intact. You can test it easily by running it with cover off and seeing if you get more performance. I doubt you will.

If you want more air getting to fhe Filter, check out Frogskinz. They’re mesh stickers designed for air box mods on snow machines and ATVs. They let air though, but keep debris out.
I looked at those Frogskinz screens and I'm going to order some of the 1 1/5" ones. Thanks for pointing them out.
 
Test with a tach and take off filter cover to see if the Rpm increase or not. See if its acting as a restriction. I suspect it isn't. Unless the air injection is sucking up fines from the front of the saw and clogging the filter, that's the only reason I'd drill holes in the rear. I'm not a big fan of air injection, I've plugged a few on my saws.

Could do that with that tach for sure just to see. Obviously if it runs faster RPM with the cover off then it got more air.

I haven’t had any issue with the filter clogging on my 390 so far, stays clean for a long time. The only thing I had to do was I have to keep a film of grease on the bottom of the filter because it’s plastic and the manifold is plastic. Shortly after buying the saw I noticed a fine trace of dust in the manifold. Cleaned up and now keep grease between the 2 and no more issues with anything getting into the carb.
 
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