Downside of the airbox mod

I recently did the airbox mod on my 00 MM700 and felt like it lost some low end punch also it made it extremely cold blooded when starting and warming up. I closed off half of the holes to see if that helps. Maybe you guys that run in warmer climates have better luck but I wouldn't recomend it for the north country.

I ran the airbox mod for along time (with pipes)..and I found it made the sled really sensitive to temperature changes. I've recently closed it up..runs better and quieter..jetting is far more consistant.

I'm thinking I'll probably end up doing the same thing by plugging off all the holes and put it back to stock. I think it messes up my tempa flow too. I have similar feelings about the head gasket mod, I took one layer out and didn't notice any difference. On a compression check it maybe raised by compression by 3 or 4 psi, nothing to write home about.

I noticed a huge difference with the head gasket mod. Cleaned the engine right up...100% better.

Also it can make the jetting a little more sensitive to elevation changes.

I'm running the ATAAC with the airbox mod and 1 layer head gasket removed on my 700 and it made it a new machine IMO. I was always fartin around with jetting before and now I just pull the rope and go. I'm running base elevation of 1500 feet in temps around +7 deg C to -25 deg C. In the warmer temps ther is a slight and I mean slight gurgle at low rpm's but open her up and she rips. I also have run the same setup, aside from clutching, up to 4000 - 7000 feet and have not had a problem!!!!

i was going to do the airbox mod last year but heard that it makes everything real finicky, and i didn't want to be adjusting stuff every hour on the trail.

TPI valves by thunder products

I have triples on my 02' viper and instead of cutting out the shelf on the air box,( I still gutted it) I installed 4 of the Thunder Products "TPI" Valves. They work awesome cuz you can adjust the amount of air going through them. Warmer days, open them up, and on real cold days, close them or move them to any of the 3 positions in between. Plus they are real inexpensive...like 10.00 bucks a piece. Just too give you another option instead of having to go back to stock. I get you guys a picture of them when I get the chance....probably late next week. Going to Gwinn 19th - 23rd...can't wait, but I'll post something soon. Oops! looking through Jan/Feb SnowTech mag and they are advertised for 16.95 a piece. I got mine when the first came out 2 years ago and they were slightly cheaper. Go to Thunderproducts.com If you are able and keep your back issues of Snowtech...in the Oct/Nov 2004 edition they did a "Snow Test" on the valves in a Viper...solid reviews...page 70.

snow guy said:

I recently did the airbox mod on my 00 MM700 and felt like it lost some low end punch also it made it extremely cold blooded when starting and warming up. I closed off half of the holes to see if that helps. Maybe you guys that run in warmer climates have better luck but I wouldn't recomend it for the north country.

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I dont know anything about the MM airbox, But on the Viper the airtubes inside the airbox speed up the air drawing more fuel. I tried my 780 w/bored carbs unvented from the airbox & airtubes inside the air box & could not fix a high idle hangup, I tried 55 pilots (Unvented 55's are huge) that was pig fat on the bottomend & ran like crap. I pulled the airtubes & dropped to 45 mains with the carbs unvented & the sled runs strong.

Snow guy flip the choke on for a couple seconds @ idle & then nail it, If it runs better you are lean on the pilots & if it gets worse your rich on the pilots. I guess it depends on if you want to tune on it anymore.


EDIT Sorry I did not catch this post was in Mountain riding. I dont know what works & doesnt work in the thin air. I do see a lot of the mountain mods run filters on the carbs over the airbox though.

I'm was really happy with the performance with my sled anyway, it jumps out there pretty good. I saw more gain with the Hartman custom clutch and helix than anything. What little more I could gain with jetting and tuning isn't worth the hassle to me, time to ride.