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Airbox

I doubt it. I personally do not care for how close that back wall is to the carb entrance, that close often leads to other issues, you get a hard reversion spike off a flat wall like that. The volume inside an airbox has a whopping amount to do with how well the box resonates to help power at certain rpm, that picced one no way is near enough volume.

Expensive glamor part in my view.
 
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I doubt it. I personally do not care about how close that back wall is to the carb entrance, that close often leads to other issues, you get a hard reversion spike off a flat wall like that. The volume inside an airbox has a whopping amount to do with how well the box resonates to help power at certain rpm, that picced one no way is near enough volume.

Expensive glamor part in my view.

THanks AMC, its not too glamorous either. Just looking for something more compact. Appreciate the feedback.
 
THanks AMC, its not too glamorous either. Just looking for something more compact. Appreciate the feedback.

"Compact" = "Bad" in this case. If anything a bigger air filter is more desirable.

My bike came with a sheet metal version of those air boxes that uses the stock rubber runners. The thinner material allows a much larger filter surface area though.

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When using a paper filter the airbox volume inside of the paper becomes a secondary resonating volume that can add or detract power.................think boost bottle on say a two stroke dirt bike. The pulse going backwards continues to move and can go into another carb back end forward to help that one if the volume is right as well as rpm. If that lines up with the normal pulsation in the carb by itself double gains. You lose that with pods too.

Some engines don't care and some love it.
 
What is the optimal volume though?

FYI - That air box I have (not by choice, it came with the bike) doesn't use a paper filter. It has a secondary expanded metal layer inside with a washable fiber filter material sandwiched between the two layers that's about 3/16 thick.

It's not a very good air filter but I don't ride the bike a lot. If it was a daily driver I'd hunt down something to fit a stock type air filter.
 
There is no one optimum size, air box volume requirements change at different operating conditions, rpm. Intake tuning is just as important as exhaust tuning and they go hand in hand. Optimum at one rpm is not at another. My CBR954 has a valve in the air box that changes air box volume at a determined rpm as well as a valve in the exhaust that changes exhaust tuning dependent on the rpm. Most of the new sport bikes do this also.
 
'There is no one optimum size...'

Exactly, cams affect the need, carb size, etc., etc..........even dead stock engines but one bigger than the other like the DOHCs need changes, ergo, 750, 900, etc., minor mods made in them to change that. The 750 used different airbox rubbers from 900 that moved volume a bit as well as the carb entry shape and the 1100 added another intake duct to mod entry pressure.

I mentioned paper filter as they have a bit of restriction that makes the airbox volume seem more solid or set in place. You could rate the volume before the air filter but still inside box as a third tuning volume too but getting pretty extreme. The bleed rate across the filter affects the CV carb slide working too, some used a K&N stock replacement filter instead of pods and just dumping the OEM paper filter to use that cost power too. The K&N simply did not have enough restriction and the OEM fuel curve as supplied by those carbs wanted that.

Hey digger, have you picked up on the fact that the higher tuned fours nowadays are getting radical enough they are beginning to sound like 2 strokes at full power and rev? I listen to them here on the freeway next door and hear them all the time, I'd swear I'm listening to hot '60s 2 strokes now.

All that wave tuning if dead on can change the sound of the engine too, get in the power band and the engine note changes bigtime.
 
My cbr954 makes a different exhaust note as the valves in the box and the exhaust move position and you do feel a difference. The bikes that really have a different sound are the Yamaha R1 with their cross plane crankshaft, they definitely have a sound of there own.
 
There is no one optimum size, air box volume requirements change at different operating conditions, rpm. Intake tuning is just as important as exhaust tuning and they go hand in hand. Optimum at one rpm is not at another. My CBR954 has a valve in the air box that changes air box volume at a determined rpm as well as a valve in the exhaust that changes exhaust tuning dependent on the rpm. Most of the new sport bikes do this also.

That's sounds pretty cool. I haven't worked on the newer bikes. I do remember the 2 strokes having slides that opened up the exhaust ports as the rpm went up.
 
I do remember the 2 strokes having slides that opened up the exhaust ports as the rpm went up.

Yes all the midish 80's up to present 2 stroke dirt bikes varied the exhaust timing with some type of slide, it worked very well and made a noticable difference in power, you noticed it if they stuck or stopped working. I ran Honda CR250 dirtbikes till they came out with the 450 4 strokes. Two stroke intake and exhaust tuning is a whole nother animal and is amazing they work and last as long as they do.

Yup modern sport bikes are indeed amazing, they make tons of power and do it reliably. Electonic fuel injection and tuning on my lap top, no jets no fuss, its nice but doesnt have the soul of old 750.

Now that this thread is so far off topic lets see if we help the original poster lol
 
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