Airfilter mod.

[Nighthawk]

Hey guys, i Want to change ny airfiltercase, to the "clamp on type" from K&N.
Before i do so, just wanted to hear og anybody have experienced problems with that?
Is it hard to tune carb afterwards? Do i have to tale it to a Dyno test?

Thank you in advance for the assistance.

[ZOA NOM]

Most here prefer these -

http://rpmracingca.com/proddetail.asp?prod=Carb%3ARPMPod&cat=39




and yes, you should address the jetting afterwards

[RPM - Robert]

You don't want to use those. Read the Foam (Uni) vs. Cotton (K&N) vs. Paper (Stock) section of this.

http://fjowners.wikidot.com/pods

Stock filtration is better than the K&N type filters with the hard back on the FJ/XJ/XJR applications

[giantkiller]

I've had k&n filter roach a hopped up (read as a lot of money/hp) atv 2stroke motor. In a short ride. New filter properly oiled. Was a dusty trail. But I will never run k&n again. Could feel the fine grit on your finger rubbing it in the carb and all through the motor.  2stroke. Run pods from Randy on all my Fjs. Just for the convenience of not having the air box  in the way. And not to mention weight savings.

[mtc]

Hey guys, i Want to change ny airfiltercase, to the "clamp on type" from K&N.
Before i do so, just wanted to hear og anybody have experienced problems with that?
Is it hard to tune carb afterwards? Do i have to tale it to a Dyno test?

Thank you in advance for the assistance.

tell me those don't look like crap



don't do it i bought a bike with those and they don't stay on for one and the outside, ones are mashed to clear the frame rails, expensive for zero reason

beside i think the stock airbox's velocity stacks do something fore the bottom end

[racerrad8]

beside i think the stock airbox's velocity stacks do something fore the bottom end

Please explain,  what do you think they do?

Randy - RPM

[mtc]

beside i think the stock airbox's velocity stacks do something fore the bottom end

Please explain,  what do you think they do?

Randy - RPM

i don't really know, i am often wrong

i though it might have something to do with a longer runner for the air path, for more low end, maybe you know...


so here is the question....

why did my xs1100 have them and why do my fj1100 have them? for looks? to to smooth out turbulence, are there no actual benefit, more weight, more material, more engineering,  more hassle to install,  for what? just decoration?

[Nighthawk]

Thank you. That helped a lot.
I'm going with the Dual pods from RPM instead.
They could also help with the carb setting.
Awesome.!

[racerrad8]

beside i think the stock airbox's velocity stacks do something fore the bottom end

Please explain,  what do you think they do?

Randy - RPM

i don't really know, i am often wrong

i though it might have something to do with a longer runner for the air path, for more low end, maybe you know...


so here is the question....

why did my xs1100 have them and why do my fj1100 have them? for looks? to to smooth out turbulence, are there no actual benefit, more weight, more material, more engineering,  more hassle to install,  for what? just decoration?

Sorry,  I too do not have the official answer, that's why I asked you.

There is all kinds of speculation and opinion of why they are there. But here are my two thought on them.

1) They there because Yamaha is restricted by intake noise requirements and they act as some sort of muffling of the intake tract.
2) Again because Yamaha is restricted by emissions and they are required to pass those restrictions.

If Yamaha had a choice, I doubt the air box would make the top 3 options.

I have never been convinced that they actually improve the bottom end (torque) of the engine. I mean compared to a true, metal velocity stack, the actual trumpet to assist in smooth airflow is very minor. In my experience velocity stack help top end, high RPM range more than bottom end. The smoother air flow at the high flow is much more important than off idle.

The one thing I do know, even though it doesn't relate to a FJ1200 engine. We have been working on two different race cars in the past couple of years. One uses an R1 and the other a Hayabusa. Both owners started with the stock air boxes that have "velocity stacks". The R1 owner tried several different way to modify the box to increase performance. The busa guy did not. But both of them were not happy with the performance.

We now have a customer made velocity stack air filter unit on the R1 and the Busa is running UNI foam filters. Both costumers are much happier with the improved performance of their race cars with the removal of the air boxes and proper jetting based on the increased air flow.

Let me leave you with this regarding Yamaha FJ1100/FJ1200 air boxes. The air must be drawn into a external snorkel with a fixed size. The air must then make several turns to get to air filter. It then has to turn again at the rubber velocity stack and then into the carbs. The intake air must make a lot of turns to get into the engine.

Aftermarket pod type air filters allow the air to be draw straight into the carbs through the filter media, no restrictive turns.

So, at the minimum I think we can all agree air, liquids and even electrical current works best with the path of least resistance.

and finally, if you haven't read this, Kyle who is a member here took a lot of time to comb through posts when discussing air filters. He then used the most important information on this link: http://fjowners.wikidot.com/pods

Randy - RPM

[mtc]

beside i think the stock airbox's velocity stacks do something fore the bottom end

Please explain,  what do you think they do?

Randy - RPM

i don't really know, i am often wrong

i though it might have something to do with a longer runner for the air path, for more low end, maybe you know...


so here is the question....

why did my xs1100 have them and why do my fj1100 have them? for looks? to to smooth out turbulence, are there no actual benefit, more weight, more material, more engineering,  more hassle to install,  for what? just decoration?

Sorry,  I too do not have the official answer, that's why I asked you.

There is all kinds of speculation and opinion of why they are there. But here are my two thought on them.

1) They there because Yamaha is restricted by intake noise requirements and they act as some sort of muffling of the intake tract.
2) Again because Yamaha is restricted by emissions and they are required to pass those restrictions.

If Yamaha had a choice, I doubt the air box would make the top 3 options.

I have never been convinced that they actually improve the bottom end (torque) of the engine. I mean compared to a true, metal velocity stack, the actual trumpet to assist in smooth airflow is very minor. In my experience velocity stack help top end, high RPM range more than bottom end. The smoother air flow at the high flow is much more important than off idle.

The one thing I do know, even though it doesn't relate to a FJ1200 engine. We have been working on two different race cars in the past couple of years. One uses an R1 and the other a Hayabusa. Both owners started with the stock air boxes that have "velocity stacks". The R1 owner tried several different way to modify the box to increase performance. The busa guy did not. But both of them were not happy with the performance.

We now have a customer made velocity stack air filter unit on the R1 and the Busa is running UNI foam filters. Both costumers are much happier with the improved performance of their race cars with the removal of the air boxes and proper jetting based on the increased air flow.

Let me leave you with this regarding Yamaha FJ1100/FJ1200 air boxes. The air must be drawn into a external snorkel with a fixed size. The air must then make several turns to get to air filter. It then has to turn again at the rubber velocity stack and then into the carbs. The intake air must make a lot of turns to get into the engine.

Aftermarket pod type air filters allow the air to be draw straight into the carbs through the filter media, no restrictive turns.

So, at the minimum I think we can all agree air, liquids and even electrical current works best with the path of least resistance.

and finally, if you haven't read this, Kyle who is a member here took a lot of time to comb through posts when discussing air filters. He then used the most important information on this link: http://fjowners.wikidot.com/pods

Randy - RPM

back when i was trying to get top end power from a TPI corvette everyone knew "tune port injection" had long and skinny runners after the plenum, that fed into the intake ports where the fuel injectors were located. the redline for those engines were ridiculously low but for that period the torque was record breaking. everyone sought to port and grind out material or buy roomy runners to raise the powerband even 500 rpm

super ram bolt on answered that with an l effective intake shorter and roomier runners, voila, pwoer habe moved up not to 4500 but now at 6000 rpm and allowed for cams heads, and stoker motors... were the stock could not support

then came the LT1 intakes with very very short runners, one had low end and the latter had top end,

this is no secret in that world of corvettes....i know this may not apply


but with the air  path essentially elongated and "tuned" with what i can see in the stock fj airbox it reminds me of the meandering pathways of  plenums and runners designed for a certain torque curve

and every time i rid the box for pod or pod equivalents, i regretted it and can never ( call me lame) tune the flat spotting and loss of low end and mids out.

so i have deduced whether right or wrong, those v stacks are ( to me) are aerodynamic in nature and reduce trubulance and creating tune restriction at the same time.

at the end of the day airbox or pod filter or foam, is there a dyno sheet that can definitively prove or disprove where each performs it's best? if there is one soley with those mods and jetted properly we can see the merits of each intake filtration system

if the engine as a whole is engineered or rather built to take advantage of the least amount of restriction, i.e. cams, porting, open pipes for max HP, may yeah

but for the street on a stock engine, with stock heavy azz exhaust, i have my doubts and believe Yamaha engineers got it right

[FJ_Hooligan]

It has to do with the velocity of the air.  NOT THE QUANTITY!

The airbox is more restrictive so the velocity of the intake air is higher than with UNI pods.  As I have said many times, when removing the airbox and going to pod filters, jetting changes are secondary to shimming the needles.

The lower velocity airflow resulting from the less restrictive pod filters causes the carbs to be lean for a given throttle setting.  We can shim the needles to compensate the mixture, but the lower velocity does not have as efficient air/fuel atomization so the combustion efficiency suffers.  Remember the YICS ports in the last generation XS motor heads? Those ports caused intake pulses from the cylinders to help disrupt the airflow and cause turbulence which causes better mixing and improves low end performance.  The first generation FJ heads have the castings lugs for YICS but they were never drilled because going to 4 valves made it unnecessary.  By the second gen, the heads no longer had the YICS provisions in the casting.

Noel documented this effect recently.  He noted that when his pod filters got extremely dirty the low end response actually improved.  As the filters got dirty, they became more restrictive and the airflow through the carbs increased causing better mixture atomization and combustion efficiency and improved low end response.

Once again, CV carbs are all about the air flow velocity.  The "high airflow capability" of pod filters really doesn't have a benefit until you reach a throttle position  where the airbox is the ultimate airflow restriction (essentially WOT).  I don't believe this is ever the case.  The size of the carb is the controlling factor on air flow into the combustion chamber.

Pod filters allow easier carb removal (which is great and a good ennough reason to get them).  But, they are NOT a performance enhancement.  At least not until full WOT.  How often you riding there?

[mtc]

cycle world don't know anything

https://www.cycleworld.com/what-is-secret-importance-motorcycle-airbox

[roverfj1200]

There is no doubt that fitting pod filters or any change to the intake will change air and fuel mixtures. Even a change to the exhaust will change mixtures.

I have fitted pods to both my FJs and found that low end response/torque are lost and it is hard to tell if there is a change to mid and top end. Changes to needle height help with the new air flow regime and some movement outward of the idle screw will help but seems only to overly enrich the fuel mix. Both my bikes are set for a trip to the dyno to sort out the issue as only a dyno can. 

[JPaganel]

And not to mention weight savings.

Yeah, saving two pounds on a nearly 600 pound bike is totally super important...

[giantkiller]

And not to mention weight savings.

Yeah, saving two pounds on a nearly 600 pound bike is totally super important...

Thanks I didn't add the 2lbs on to the 42lbs I've shaved off the 1350. It was already off when I got it. 44lbs

Should bring it down to 527 wet.