stock air box vs open filter

**STiForester** · 12-22-2011, 06:46 PM

ok so i got the new parts all on it and it idles great but has absolutely no power at all when i ride it! wants to cut out kinda but doesnt. just has NO pickup and i dont have anything on it not even a filter... i talked to a few people and they told me it has to be jetted to run an open filter... the setup it came with had the air box and filter.... does it really make a difference in the way it runs?!

**STiForester** · 12-22-2011, 06:56 PM

this is frustrating because im so close to having it run great but i cant figure it out with this filter issue and i dont wanna have to order one if i dont have to

**dougspcs** · 12-22-2011, 07:14 PM

UMMMM..just stating the obvious. You are asking for help and giving us this to work with!!

At least tell us what kind of machine it is!!

**STiForester** · 12-22-2011, 07:20 PM

85 tecate... 300 main and i believe 40 pilot... aftermarket exhaust but i have no idea what kind and it is ported... new intake boot and fresh clean.. new kicker gear and new gasket on the covers.. starts right up and idles fine. when i crack on the throttle in nuetral i sounds fine.. when in gear i take it around and it has no power and sounds like it wants to break up but doesnt,,, feels like something is holding it back from going or weighing it down... after a minute or so of riding i pulled he plug and it was pretty clean but a little wet... smelled like 2 stroke and not burnt.... everything seems normal but the plug is wet and doesnt wanna go at all... im stumped and frustrated.. i called the bike mechanic around my way and he said without the airbox and filter it will never run right... says its running lean but i dont know at the point.....

**blkstangman88** · 12-22-2011, 07:21 PM

Yes there temperamental no matter what machine u have. My 100% stock 07 yfz450 wouldn't run when all I did was put a k&n n left the lid off. Most likely

jetting

**RIDE-RED 250r** · 12-22-2011, 07:24 PM

Yes, there certainly can be a need to dial jetting in when running no air filter.

In my personal opinion, I would not run an airbox eliminator when running in an area where it can be wet/muddy. The airbox provides more protection against the engine gulping water in if you hit waterholes and whatnot.There are different schools of thought on this, but that's my opinion.

There are things you can do to improve airflow with the airbox. You can run without the lid, or take a 1" holesaw and cut 3 or 4 holes in the top of the lid. Or you can do what I have done and remove the snorkel connecting the airbox to the main frame backbone (under the tank). Now, doing these 2 things will increase the chances of getting some water to a degree, but not so much as running a straight pod filter on the carb. Also, running no airbox, airbox lid removed, snorkel removed, or cutting holes in the lid will cause you to need to clean/replace the air filter more frequently, especially in very dusty conditions.

I would also note that since I removed my airbox snorkel, I had to richen the main jet 2 or 3 sizes.. I can't remember exactly as it was a couple years ago when I did it.....

Again, this is one man's opinion based on one man's personal experience....

Hope that helps....

**STiForester** · 12-22-2011, 07:28 PM

thanks that helped a lot... i have the stock air box and it has vented holes on the lid.. 3 to be exact.. im going to get a stock filter and try that.. everyone wants $50. f that i found one on ebay for $15 shipped..

**hoosierlogger** · 12-22-2011, 07:34 PM

Originally Posted by STiForester

thanks that helped a lot... i have the stock air box and it has vented holes on the lid.. 3 to be exact.. im going to get a stock filter and try that.. everyone wants $50. f that i found one on ebay for $15 shipped..

Ill bet its a good one!!!

**STiForester** · 12-22-2011, 07:38 PM

i hope so lol.. its new in the package, so well see.. looks oily....

**Dirtcrasher** · 12-22-2011, 07:52 PM

If you haven't already, pop a K+N filter on there and start by jetting fat, then work your way down.......

By removing the air box, you have allowed an unrestricted air opening and need to compensate for fuel.

Great for drags or dunes but will only wreck havoc on any type of trail ride that includes water.

C'mon! Never run anything without a filter or enjoy rebuilding the engine while the rest of us are tearing it up

You like breathing dirt? Neither does your engine........

**STiForester** · 12-22-2011, 08:15 PM

I had it off due to the bike arrivin at my house in pieces and the motor was in a out so I didn't bother to put it to see if it ran in case everything had to come back out ya know. And I put the stock one on. I've heard you need to change jetting with it. I'm not trying to tinker more than I have to

**RIDE-RED 250r** · 12-22-2011, 08:18 PM

Bottom line, get the filter/airbox on there and see how it acts. If you even think it may be lean, shut 'er down and check the plug condition..... Make jetting adjustments as necessary.

Like DC said, set it up rich and incrementally work your way leaner.....

**STiForester** · 12-22-2011, 08:23 PM

Stock filter... And jetting with the k&n. Just to clarify

**jeswinehart** · 12-22-2011, 09:04 PM

Well, there again if you do not use a stock air box properly mounted it is gonna be very hard on your intake boot.
All that would be supporting the carb would be the intake boot and add in the factor that Tecates kinda vibrate a little bit (LOL~ did I say a little bit),,
If you decide to simply hang a K+N on the end of I highly recommend to secure the carb in one fashion or another.

**STiForester** · 12-22-2011, 10:06 PM

yes but I'm just going to put the air box back on and stock filter... thanks for everything tho john, runs much better with the new boot

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stock air box vs open filter