DIY - Removing the air filter box (oh my!)

[Jiggles]

Originally Posted by thomason2wheels

I dont think i want to disassemble the whole bloody bike just to dump the airbox.....too much work and even after all that, its still just a 250... :-D

It only took me about 3 minutes to get the airbox out

Link to original page on YouTube.

And then you get to take out your frustration on the airbox

[webfoot]

what a great help, than you, am doing this as soon as filter arrives, Man, dont look forward to all the busted skin with that air box, but being a retired sailor, I have the vocab for the job, hahaha

[subxero]

follow the instructions and it is easy. Don't try and take short cuts. If you can't get to a screw take off what needs to be taken off to get to it.

I did this few months ago and it was a breeze, It took me longer to adjust my needles and change my jets than it did for me to pull airbox. Primarily cuz i did not have a JIS screw driver and i fumbled a bowl screw and it got jammed in by the generator? whatever and i did not have the right pliers at the time to get it out, took forever to get damn thing out with screw driver

[Mhancock309]

@VeX, I know this post is dated but can you give the part # for the breather you used? I'm in the process of doing some mods and clean up and I really like the simplicity here.

[CHAZERR]

After finally having removed and rebuilt carb with factory pro jets plus replaced the airbox with a K&N 0990 ---- I for the life of me cannot remember where the the idle adjusmtent knob attaches to?????

It's on the bottom of float bowl? float bowl screws?

If so-- I rippin it back down!

Anyone?

2007 250

[headshrink]

Originally Posted by Mhancock309

@VeX, I know this post is dated but can you give the part # for the breather you used? I'm in the process of doing some mods and clean up and I really like the simplicity here.

I haven't seen him around these parts in along time. If you look at whats displayed at your local auto parts store, it's probably one of two choices. It's been a while since I did it, but I do remember that once you see it it's obvious.

[martinizing]

Hi

I know this is super old post , but which filter is better

Rc 2370 or R0990?

Thanks

[Mbene]

Bump

[Mhancock309]

Ok so I did this mod a couple years ago. Last year I could not get my bike started. (That is a separate issue now resolved). Today I got is fired up for the first time since the pod mod, rejetting etc. I went for a short ride only to have oil spewing from my breather. I mean A LOT of oil, enough to coat my entire rear wheel. Fish tailing on an oil slick is pretty unnerving. Anyway how do I eliminate oil pouring out of the breather? Anyone got a good solution?

[Triple Jim]

You'd probably get more help if you start a new thread, but oil pouring out the breather could be a sign that you have way too much oil in the engine, or that your rings are not sealing. Start by checking your oil level. It's not impossible that your petcock leaked gasoline into the engine all winter, for example, and now you have a lot of fuel/oil mix in the crankcase.

[Momaru]

Possibly silly question @Mhancock309, but do you have a filter over the crankcase breather port? There can be a good bit of spatter if it's not covered

[Mhancock309]

Thanks Triple Jim. I was having trouble with my iPad not letting me start a new thread. I did check the fluid level and it was high. Drained it and found fuel mixed in. Momaru, I do have a filter on the port but it still got all over. I think problem solved...

[Triple Jim]

What was it, leaking float valve and leaking petcock?

[Mhancock309]

I replaced my ignition with and aftermarket unit not knowing that I needed a 100 ohm resistor for the grey wire so after cranking my bike and flooding the carbs several times gas must have gotten into the crank case. But thanks to this forum I've been able to figure these things out

[Triple Jim]

You probably already know, but keep an eye on the oil level for a while to be sure it was just cranking that did it. It seems a little unlikely that you cranked so much you raised the oil level, but unlikely things do happen.

[maverick9611]

15 min.

[maverick9611]

coming over from zrx's, pods are the norm. we wired them up to hold em in case they came off. i will look into doing this on the 250. will be using stock air box runners too.

[maverick9611]

another trick is to install this and run breather line higher up. this will eliminate condensation build up in crankcase. must run valve in vertical position. i'll post a pic when i do mine. i don't know if this is a issue with the 250r but zrx 1100/1200 under cold environment short runs would build up condensation on oil level window.

[pb3]

Originally Posted by maverick9611

coming over from zrx's, pods are the norm. we wired them up to hold em in case they came off. i will look into doing this on the 250. will be using stock air box runners too.

hey maverick just curious how you fared, especially with use of the stock airbox runners?

[maverick9611]

Originally Posted by pb3

hey maverick just curious how you fared, especially with use of the stock airbox runners?

no change. actually i’m working closely with member dannoxyz on jetting experiments with pod filters. so far everything we are doing is cutting edge and will turn the pod community upside down. we are going to prove the airbox must have is a myth and proper tuning can be done with pods. problem is dyno jet and factory pro are giving jet kits that are quite rich. factory pro gives 110,112,115 mains. these are are way to big! to make maximum power, lean mains need to be installed!with danno’s as a guide, the exploited ninja with uni 6”pods is now skirting near stock main jets! i’ve tried 108’s, 102’s,100’s and now heading towards 98’s. keep in mind elevation will factor in too. augusta, ga is 132’ above sea level.

[DannoXYZ]

I think there's some quantitative analysis that's overlooked here. Coming from bigger bikes, it was common to go with pods for performance-increase. Due to packaging constraints on bikes, there's limit on size of airbox and filter. Removing them on 750-1000cc bike and replacing with individual filters increases filter's surface-area and reduces restriction. This improves high-RPM flow and power.

However, on Ninja-250, with similar sized frame, tank, seat-height, etc., it has airbox and filter of roughly same size as 600cc supersport bikes! Filter on my 250R is about same size as my CBR600RR's! A bike with 5x air-flow and 5x power! So I concluded that filter and airbox on 250R doesn't pose any restrictions nor does it rob any power.

Talking with other racers backs up that conclusion as none of them have removed airbox for power-gains. Perhaps use K&N-type cotton washable filter for longevity. Even racers in 250 Superbike classes which allows for airbox removal don't do it. And racers will and have tried every dirty trick possible for advantage! I've tried searching for and asking for before-and-after dyno-charts of pod-conversions on 250s, nothing.

Many street riders report that pod filters cause them fuel-metering issues in partial-throttle mid-range and that bike is sensitive to crosswinds causing hiccups. Reverting them back to factory config alleviates all these problems. Such as this case: https://www.ninjette.org/forums/showthread.php?t=84623

Other topic is carb-tuning process, which I'll go over once I dig up info...

[DannoXYZ]

Other aspect of quantitative analysis that's incomplete is with carb-tuning. We should be aware that new-gen bikes are VERY different from pre-gen bikes. Engines are tuned completely differently with different cams-profiles, head/port shapes, valves, exhausts, ignition-maps and of course, carburetor configurations. This entirely affects characteristics of engine and power-output

pre-gen 1988-2007


new-gen 2008-2012 - from Motorcyclist comparing with other small bikes


And dyno-chart comparing them, roughly ~6% difference.


Pre-gen vs. New-gen summary
5.75s vs 6.90s - 0-60 time
14.59s vs 15.30s - 1/4-mile time
87.82s vs 84.15mph - 1/4-mile speed

Performance figures between them also roughly reflect power-differences, although lighter pre-gen takes bigger lead from stand-still.. Riding them back-to-back, I can feel differences in power-output, but barely. For butt-dyno to really distinguish, you need at least 10% variation.

That ~6% power-difference is part of carb tuning configuration from factory. Which should be used as baseline for all mods and adjustments:

Pre-gens = 105 main jets
New-gens = 98 main jets

Roughly same ~6% difference repeats itself. Be very, very aware when you are talking about jetting changes, which model you're dealing with. Pre-gen or New-gen; what works for one will not work for other!

[maverick9611]

i tried both. even tried k/n with airbox intake trick. no change. i left the uni’s in because they look cool!

[DannoXYZ]

One big gain can be had on new-gens by removing snorkel from air-box. That's tiny straw compared to size of air-box and filter.

[maverick9611]

Originally Posted by DannoXYZ

One big gain can be had on new-gens by removing snorkel from air-box. That's tiny straw compared to size of air-box and filter.

[Burphel]

Keep in mind, a lot of racing orgs require a stock airbox. You'll be fine for trackdays with pods.

I've kind of always wondered why, but there it is...