74 JD Air Box Options

mikehjd · Post by **mikehjd** » Sun Jan 04, 2009 7:27 pm

I have a couple of sleds with walbro carbs that are missing the air boxes. Has anyone had any luck making one or what would work as a option? I made one out of a soup can and opened one end and put a cloth on the end to restrict it. Will this work or am I looking for trouble down the road?

thearcticfisherman · Post by **thearcticfisherman** » Sun Jan 04, 2009 8:47 pm

I would just put a airhorn on it

mikehjd · Post by **mikehjd** » Sun Jan 04, 2009 8:48 pm

Doesn't it need something to restrict the air?

JDFanPa · Post by **JDFanPa** » Mon Jan 05, 2009 3:02 am

no walbro sleds can be run without an airbox

400brian · Post by **400brian** » Mon Jan 05, 2009 3:47 am

Andy, I think you left out an important comma in your post. :lol22:

The air boxes used to be on ebay regularly, but it has been a long time since I've seen one.

The '72s ran an air horn with some coarse foam in it, after that they ran air boxes.

The air box does two things: 1) it muffles the carb noise a bit. 2) it catches the fuel spit back that piston ported engines produce. That helps keep things a bit cleaner. If you run the sled without the air box with the engine cover off, you'll likely find fuel on the front of the seat after riding it for a bit.

Try putting an ad in the classifieds that you are looking for one. To be correct, you need the box, hose, and the aluminum spacer if its for a piston ported engine.

Walbros are tuned by turning the mixture screw for any given condition, thus they can be run without any intake restriction. Mikuni equipped engines require an air box only to run with the installed jetting. They can be re-jetted to run without the airbox.
Power jet Mikunis are a different deal .

mikehjd · Post by **mikehjd** » Mon Jan 05, 2009 3:56 am

Thanks for the help Brian. I have seen lots of walbro JD's without the air box. What did it do to them with them off, did they have more power?

400brian · Post by **400brian** » Mon Jan 05, 2009 3:59 am

The original foam was real coarse, you could practically see through it.
And there was hardware cloth type screen on both sides ( in the airhorn type ).
A foam sock on the end of the hose on the airbox type.

Live it up.

400brian · Post by **400brian** » Mon Jan 05, 2009 4:03 am

Taking the box off only makes them louder!

Either the previous owner tired of putting the box on and off, or the screws rattled out and they threw the box out, or the threads stripped out in the carb horn, so they tossed it.

mikehjd · Post by **mikehjd** » Mon Jan 05, 2009 4:04 am

My other 300 has the original airbox and it has that course foam on the end of the pipe with wire mesh to hold it in place. It seems like alot of the airboxes were taken off and pitched.

GreenSpeed · Post by **GreenSpeed** » Mon Jan 05, 2009 9:20 pm

There's one on ebay right now: Item No. 310113725395 Just put the number in and hit search.

-John

DLDeere · Post by **DLDeere** » Tue Jan 06, 2009 12:57 am

I saw it also. Here is the link.

http://cgi.ebay.com/ebaymotors/John-Deere-400-500-600-X4-X6X8-Snowmobile-Walbro-Airbox_W0QQcmdZViewItemQQ_trkparmsZ66Q3a2Q7c65Q3a1Q7c39Q3a1Q7c240Q3a1318QQ_trksidZp3286Q2ec0Q2em14QQhashZitem310113725395QQitemZ310113725395QQptZSnowmobileQ5fPartsQ5fAccessories

JDFanPa · Post by **JDFanPa** » Tue Jan 06, 2009 2:42 am

400brian wrote:Andy, I think you left out an important comma in your post.

Brian I thought after I graduated I didnt need to use them anymore but I now see your point. Ive got most of my air boxes off my walbro sleds honestly. I like being able to squirt some pre mix in the carbs to get them started after along time setting. I see no other benifit in not running them. But it will do no harm.