hi there i would like to get rid of my airbox and use some sort of uni filter or one someone suggest i have stock setup on bike its a nsr 250 r mc 21 wet clutch what mods do i need to do to make this work the airbox is such a pain in the ass thanks for any help
Do the wire splice then just take the airbox off and get the jetting right, it'll work, make a racket and go slightly slower than it would have with a modded airbox on (unless you keep it above 10,000rpm all the time).
Put pod filters on and you'll lose 1/2 of the top end gain you got with no filter, you won't get back the mid range you'd have had with the air box on and it'll still make a racket. _________________ Please do not PM me technical questions, if you can't find it on the Forum start a thread
OK THEN HOW DO I MOD THE AIRBOX AND THE RUBBER BOOT SEEMS HARD IT WON'T STREATCH OVER THE CARB END AT ALLLLLLL!!! IS THERE A WAY TO SOFTEN THE RUBBER AGAIN SO I CAN STRETCH IT OVER OR DO I JUST NEED BIGGER BALLS AND GET IT ON LOL !! THANKS FOR ANY HELP BRENT
My Fizzer is like that....Immagine how hard it is with four carbs. I heat it up to soften the rubber(blowtorch(be careful!)).. But you got to act fast or they get hard again quick !! _________________ MC21
04 NSR50R
93 CBR F2
98 CBR F3 track bike
95 VFR750
89 FL400R Pilot
90 FZR 4/600
warbird110 wrote: IS THERE A WAY TO SOFTEN THE RUBBER AGAIN
Pot of boiling water usually does the trick. _________________ MC21SP Plaything
BMW F800GS Bumblebee
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Even if it didn't... the noise is well worth the expense!
I've got ramair for it now, but can't bring myself to fit it! Too quiet!!
How do you know it goes "better" with no airbox? Have you actually spent a day on the dyno trying? It may well go very well right now will for sure go better without those silly bits of foam on and with something to hold a decent amount of still air around the carbs.
And indeed the 250's at the GP where really quiet coming towards you but as I've argued before form should follow function, not the other way around. _________________ Please do not PM me technical questions, if you can't find it on the Forum start a thread
But as every Max Power reader knows, louder = faster.
Next mod for Andy is the blus neon lights under the rear swing arm... _________________ MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball
So, wy is that you loose power with pod filters? Is there any way to correct that? Is this true of most bikes, or just the NSR? _________________ james
Its not how fast you go...Its how you go fast.
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Pod filters ultimately (just like any other filter) restrict airflow. I run mine dry, as even oiling them is more restrictive than running them dry. They are only there really as a token gesture against the worst of the crap trying to get in and destroy my motor.
The stock airbox for my setup is too small, and pretty much too small for anything other than an SP motor. The filters perform better than the airbox, but would probably perform better still in an HRC carb shield. (It's not really fair to call it an airbox.)
Fontyyy only runs his airbox if he has to, i.e. on quiet(ish) days where the open carbs are too loud. Other than that, it's open carbs on his '28 for top-end power, and that's what I want. My 250 is about screaming, not mid-range (although it's one of the strongest production 250's to ever run on GT's dyno - even with NO airbox!), but I guess it's nice that I have both top-end and grunt... oh, and noise.
Yes Fontyyy, the GP bikes may well be quiet coming towards you, and noisy going away from you with ramair, but they really do need every single hp they can get, and so yes form must follow function for them. As I am just a poser wannabe, I want my bit of top-end and the noise of the carbs and rattly clutch with no dampers! _________________ Andy.
NSR-WORLD.COM
Please keep all responses to Forum posts on the Forum so that others may benefit.
Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.
I used a blowdryer (on high) on my rubber tubes and it made them very pliable! Smearing a little grease inside the tubes help to slide them on as well...
Your engine is quite simply a pump. It sucks air in one end and blows it out the other. However, along the way is grabs some petrol, which atomises into the airflow. this is then squeezed into a small chamber and ignited. The ignited mixture heats up and pushes the piston down, and the hot gasses from the explosion then exit through the exhaust pipe.
Now, to get max power there's way to many parameters to go over in one post, so let's just stick with the air and fuel.
I was told many moons ago by a very creditable engine builder that the trick is not to try and lean the mixture off to get power, but to try and get as much air through the motor as possible and then match the petrol with the air in a perfect ratio.
A good example would be that you've got the bike on the dyno and it's making "this much" power with the air filters in place. The problem is that it's a tad rich. So we can either lean the fuel off to get the right air/fuel ratio with the filters fitted, or we can try to get more air in there by taking off the filters. More fuel and more air (more oxygen) means a bigger bang so more power.
That is assuming that the filters are the restriction to the airflow of course, and not something else like tiny reed valves etc etc.
When testing pod filters on the brake I could always find another 2~4 ponies by throwing the filters in the bin and running open carbs.
The NSR airbox isn't all bad, but it does need some major modifications to get the best from it.
ok thanks matt what do i do about the hose thats supposed to go to the air box from the powervalves because i think i have the wrong airbox i think its to mc28 it only has one spot for hose it looks like and it goes to this little open square on top of the airbox in front of it that looks like it does nothing but collect dirt because theres no cover on that part thanks for any help brent
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