Air filter keeps falling off?

M

MissionMtnMax

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Joined
Jan 30, 2012
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18
Age
63
Location
St. Ignatius, MT
On my '99 mm 700, I have three individual air filters at the carbs. The middle one is right against the steering shaft and after a couple miles of riding it always falls off. It's been "formed" to fit there but I can tell it has been an issue with previous owner as the hose clamp is worn out on that filter - can't tighten it down anymore. So I switched hose clamps and got it good and tight on the middle carb, but 10-15 miles later it was off again. Any suggestions on how to handle this?

This was first time out on the sled since buying it last weekend. Ran great and no other issues other than air filter.
 

Maybe figure out a way to use a couple of zip ties to help keep pressure forward towards the carbs? I have also seen some guys use aliminum channel to build a support for the filters. They usually use zip ties around the filter to the bar after they get the bar mounted. Just a thought.
 
There should be a nipple type flange on carbs originally for air box boots. If your not getting it on far enough/over that nipple it will be prone to falling off. You should be able to get some sort of regular hose clamp from hardware or auto parts store. The best modification that I have seen for this was some aluminuim flat stock with holes for outer end of filter to pass threw and limit their movement to around 1/8 inch in any direction. You could always pick up an airbox and put it back in. I have never ben a fan of the individual filters. Kind of hard to equalize air intake and could easily burn it down with a filter missing.
 
You could always pick up an airbox and put it back in.
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This^

Or try to find filters that will fit better. I know when I put UNI pods on my old 670 they had angled filters available.
 
Engines with the pods don't run right compared to the stock air box system. The po probably thought he was going to get more power, all you do it pull in hot air and steam from under the hood, makes tuning a nightmare and any changes in weather will greatly effect it. Your best bet is to get a stock air box and get it set back up. The mountain max has a cold air intake pulling the air from just above the steering column so it stays free of snow dust and isn't effected by under hood temperatures.
 
Really hard to say whether or not carb tuning/adjusting would be necesary as we dont know what there at now. Take a walk threw the carbs, log what settings are curently. Clip position,mains,what size pilots. Take a look in tech pages and see what stock is. Do a search or two and figure out what other guys are currently running in similar sleds. Pipes,cans,stingers will all change settings and I dont recall if you mentioned any of that in original post. Afterwards check your plugs and the wash on pistons to verify good to go. When we picked up a sled (especially older) thats prolly had multiple owners you almost have to give EVERYTHING a once over to identify any potional problems caused by previous owner being clueless or only knowing enough to be dangerous!
 
The sled has Bender pipes and the air filter pods. That's the only mods I can see having been done. With the paper work I received from previous owner, about $300-350 was spent on a carb. adjustment/tune-up - and that was done 30 miles and over a year before I bought it. So it hadn't been used. I put new plugs in it this past week and then took it on a 40 mile run over various terrain Saturday - pulled the plugs afterwards and they were burning clean.
 
A couple of bucks said:
Are those pods ...... new looking. Like they were put on not too long ago?
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Yes, I would say they look newer, but no idea when. Like I said, the invoice from early Nov. of 2010 showed 30 miles on the sled since then and until I bought it.
 
It sound like they were installed and then the previous owner gave up on jetting so he sold it to you.
A MM w/o an airbox is like a dirtbike w/o an air filter. Your sucking steam in(with those pods) and the pressure difference is playing havoc w/ the carburation.
 
Boots, the air filter that sits on top of the air box, clamps (they're narrow so you might have a hard time finding them locally), screws that hold the lid on, the screws that attach the cdi box and coils, and the bolt that holds the top of the box to the bulkhead. I'd recommend posting a wtb ad here and try to get everything from one seller.
 
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An update on the sled. I did get an airbox and boots off of ebay that arrived late Friday - had a poker run already planned for Sat. morning, so didn't have time to change it out. I had fixed the middle K&N filter so it would stay on and it did for the entire 40 mile poker run.

But about 20 miles into the run, the sled started running very sluggishly. Could tell it was getting way too much fuel or not enough air. I checked altitude when it started doing this - was 5100 ft. - the weekend before I was running at 4600-5000' with no problem, but I stopped a lot more. So I wondered if the lack of cool air thru the pods was causing the issue and I limped on in to the warming hut. It idled fine, it started right up each time, but it was just bogging down bad - all I could do was just run it around 5000 rpm and putt-putt along. Pulled a plug - it was a bit oily.

So got to warming hut and shut it down for an hour or so. It was basically 10-15 miles downhill back to the truck - I was curious whether there may have been a jetting issue for the elevation and that it may improve as I started going down hill. So we took off - and it ran fine the entire way - didn't need to drop in elevation. The other thing I noticed was the terrible gas mileage - I used over a 1/2 tank for this 40 mile trip while my wife's MXZ 670 didn't even use a quarter tank.

So I concluded the issue was less around jetting and more around the K&N pods and sucking warm air. Sunday, I pulled the pods off and installed the
air box. I didn't pull sled off trailer, but fired it up. What I noticed right away was that instead of clutch trying to engage around 4200 rpm as it always had done, it was pulling on the tie down straps right at 3000-3200 rpms. So I'm hoping to find time this week to run up to where I made the first run with it and just run it like I did at poker run and see if it will bog down at all. We have another poker run of same distance this upcoming Sat. and I'd like to see if this airbox makes a big difference - it sounds like it should?
 
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My clutch grabs right at 4800rpm per the book, sounds like somethings up with the clutches. There shouldn't be any change in engagement rpm just because the air boxes got put back on.
 
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