Topic: Air Filter & Stack Filter Kit for 550's & 750's / The end, see post #898, pg 36

[FrankenFrankenstuff]

The whole setup will prob weigh less than a pound, I am sure the stacks will hold them in place just fine. My only problem is how easy it is to just make one. I have some stainless mesh screen, a Bridgeport, some foam and a stencil that says "FB".. It is funny but, the farther I go from stock the more i regret it..and now have to buy back all of the parts that I sold off because I thought I was smarter than the engineers at Honda 30 years ago.

[seanbarney41]

Really interested in this!  Always wondered why something like this hasn't been available before.  Subscribed and apprehensive about the price.

[Skipper]

These look great I'm planning to lose the battery on mine and these might be the finishing touch I need to get rid of the side cases

[Tintop]

Really interested in this!  Always wondered why something like this hasn't been available before.  Subscribed and apprehensive about the price.

That was my question, and why I decided to do something.

Given ITG's quality, the limited volume, and custom nature (including stacks); it still looks like the kit price will be competitive.  Of course given it is in a field of 1, it's a bit of apples and oranges.  That said, I am only waiting for final pricing on the stacks to establish a kit price.  That should happen in the next 2 weeks.

[juice]

[quote That said, I am only waiting for final pricing on the stacks to establish a kit price.  That should happen in the next 2 weeks.
[/quote]

cant wait!!

any idea how bad the carb tunig will be??

[Terry in Australia]

It's like "Field of Dreams" Brian, "if you build it, they will come"! 

[Tintop]

It's like "Field of Dreams" Brian, "if you build it, they will come"! 

Thanks Terry, it does seem to be something that has sparked interest.  

Good news on the 'how soon' front.  ITG has contacted me to say the 1st two prototype filters are made, and ship Monday; and the 1st set of revised 750 stacks are about 2 weeks away.

[quote That said, I am only waiting for final pricing on the stacks to establish a kit price.  That should happen in the next 2 weeks.

cant wait!!
any idea how bad the carb tunig will be??
[/quote]

I have organizied to have the filter tested on a 750 1st.  Mainly because the tester has multiple examples in different tune.  This will give a base line for a couple of configurations.  This should also point toward 550 tuning requirements with the new filter / stack setup.  While that is on going the 1st 10(+?) production filters will be ordered.

As for pricing.  At the being of this thread I indicated that I thought the price would be - about the same as x4 new K&N 750 filters and a set of custom stacks.  Given you can get K&N's and stacks, for about $35/each, that's $280.  More than most SOHC4's are going to spend, no matter how good the product.   Actually it looks like a ready to install filter kit will be about $235/240 Cdn for SOHC members.  Retail will be about $265~.  For a variety on reasons (mostly government red tape  ), I am arranging for CMR Racing Products to handle the import / stocking / shipping.  Details to follow.

[wannabridin]

Well keep us posted as you already are!!

How durable/long lasting is the filter material?  Cleanable/reusable?  Can't wait to blow some xmas money on these instead of presents for the gf, haha!!

[Flying J]

Yeah, im in if it solves some of the tuning issues that pods create.

[Tintop]

Well keep us posted as you already are!!

How durable/long lasting is the filter material?  Cleanable/reusable?  Can't wait to blow some xmas money on these instead of presents for the gf, haha!!

The filter is cleanable / reuseable.  There are a number of foam filter cleaners, and foam filter oils on the market.  ITG have their own as well, which I will be using.  I will be including instruction sheets with each kit covering proper cleaning and oiling.  All the kits will come with the filter pre-oiled, ready for immediate use.  As well I am currently putting together a list of suppliers who's product(s) meet the requirements to safely clean, and/or oil these filters.  These will be brands that you can source at your local bike shop.  This list will also come with the kit.

On an other note, someone asked about weight.  Looks like it will be about 330/335gm.  That's about 12oz, or under 0.75lb.

One other bit of trivia for you specification buffs.  In terms of capacity, the filter is rated at 300hp.   This is based on the surface area.  So air filter restriction of the air flow, is a non issue.

Yeah, im in if it solves some of the tuning issues that pods create.

As I have mentioned previously, it is has been shown that retaining stacks greatly improves tuneability, over pods.  The most common method in the past has been to attach a K&N to the back of the stock plenum / stack combo.  There is currently a thread in SOHC4 on doing just this.  The problem with this is you still have restricted breathing.  Why?  Because the size of the opening that the K&N attaches to is generally less than 1/2 the size of 2 carb throats, and there are 4.   In the thread (for a 550) the opening is 51mm, but each carb throat is 36mm.  Enough said.

[juice]

cool, sounds great!!

[Flying J]

Sounds good. Question though. Is this going to fit between the carbs and the frame on the 550? Some pods are to deep for the 550 so it seems like a stack with a fillter might be to long to fit. I guess we'll find out when you get the first set.

[mystic_1]

As I have mentioned previously, it is has been shown that retaining stacks greatly improves tuneability, over pods.  The most common method in the past has been to attach a K&N to the back of the stock plenum / stack combo.  There is currently a thread in SOHC4 on doing just this.  The problem with this is you still have restricted breathing.  Why?  Because the size of the opening that the K&N attaches to is generally less than 1/2 the size of 2 carb throats, and there are 4.   In the thread (for a 550) the opening is 51mm, but each carb throat is 36mm.  Enough said.

Perhaps not enough said.  Only one carb at a time is ever drawing on the intake.  You don't need an opening 4x the size of a single carb throat in that scenario.

Additionally, one of the main issues with pods is the loss of vacuum differential between the intake point and the intake valve (vacuum source).  When you remove the stock airbox and replace it with pods, you are in effect moving the venturis of the carbs closer to the intake point and therefore atmospheric pressure.  End result = less vacuum at the venturi.  TwoTired has discussed this phenomenon before.  So, this filter arrangement might do the same thing and have the same issues.

Having said that, I think this filter arrangement looks good, similar to the Henry Abe breadbox filters or K&N oval dual-carb filters, but with integral v-stacks.





mystic_1

[Tintop]

I must say mystic_1, that's the 1st photo I've seen of a HB Breadbox were someone has tried the create some space for the stacks to breath.

This package is based on using the original 550 or 750 stack design.  Below is my 550 with 77/78 550 stacks.  The back plate in my original posting, mounts were the stock sealing rings are.  The difference is that instead of the original bell mouth design (past that point), it is replaced with a solid 'rolled' entry which also replaces the inner sealing ring.  As it maintains the same shape and working length as the original, this will avoid the pod air pressure drop problem.  On the 750 stack the mounting rings are moved to the end, like the modified 550 one will be.



Not sure about your math.  But a 550 has a cylinder capacity of (550/4) 137.5cc.  So each carb is handling 137.5cc of charge / intake.  That's already ~240% of that 51mm hole.  The advantage I see in the foam filter is that it allows 180 dregrees of the stack mouth to be exposed.

[FunJimmy]

Any chance of getting this system to fit a set of Keihin CR carbs on a 550?

[mystic_1]

The problem isn't so much the location of the end of the intake tubes, you must take into account the size of the airbox.  The intake opening of the airbox is at atmospheric pressure, the intake valve is at maximum vacuum, and the relationship of the venturi to these two points determines how much vacuum you'll see.  This is why modern sports bikes have tuned airbox sizes.  Also, look up something called Helmholz Resanonce, that's also a factor here.

mystic_1

[Terry in Australia]

Geez, I just threw out one of those old breadboxes, are they any good? If so, I'll pull it back out of the trash! 

[mystic_1]

The chopper folk seem to like them a lot, might be worth eBaying if it's in good shape.

mystic_1

[Tintop]

The problem isn't so much the location of the end of the intake tubes, you must take into account the size of the airbox.  The intake opening of the airbox is at atmospheric pressure, the intake valve is at maximum vacuum, and the relationship of the venturi to these two points determines how much vacuum you'll see.  This is why modern sports bikes have tuned airbox sizes.  Also, look up something called Helmholz Resanonce, that's also a factor here.

mystic_1

With a breadbox style filter it is all about the distance between the end of the stack and the inside face of the plate opposite it.  Current stack & filter design specifies a minimum space equal to the carb throat (not venturi).  On a 750 that would be ~40mm, a 550 ~35mm.  Anything less than this and the plate is acting as a choke, and restricting air intake into the stack mouth.  With the HA breadbox using the stock 750 stacks' original mounting position you have about 25mm clearance.  It's why I noted the picture you posted, that was mounted farther out.  The other problem with the HA filter is the poor surface area.  That pretty chrome grill doesn't have a very good void ratio.  A guess would be it's around 50%.

It is not as if I haven't looked very closely at what was, and is available for our SOHCs.  My 1st priority was to find something to fit my 550 (while retaining the stock stack length).  I have spent many hours/days searching.  Dissected my HA breadbox, looked at using a K&N in a breadbox design, stacks with socks (single & dual), and adapting an automotive filter.  The big problem with the 550 is clearance.  To both the frame, and the bell crank.  The only design that fulfilled all of my criteria was foam, and only then if it was custom made to fit.  The nice thing is, it will work for the 750 as well.

Helmholz Resonance, the NASCAR 3 wave rule, both relate to tuning total intake track length.  I haven't changed that from Honda's original design, and am inclined to think they probably got it right.

Geez, I just threw out one of those old breadboxes, are they any good? If so, I'll pull it back out of the trash! 

The chopper folk seem to like them a lot, might be worth eBaying if it's in good shape.
mystic_1

Good to know that mystic_1.  After I polish up my HA, I'll be sure to target choppers in my eBay listing.

[Terry in Australia]

Woohoo! I just found another one, so off to EBay I go! Brian, you sell yours first and then I'll target the guys who missed out first time around........... 

[Tintop]

Woohoo! I just found another one, so off to EBay I go! Brian, you sell yours first and then I'll target the guys who missed out first time around........... 

I've still got to give mine a buffing.  Want to make sure the chrome shines for the choper guys.   So you can test the waters 1st.

[hesselfuzz]

Count me in, depending on price of course.

[Tintop]

Count me in, depending on price of course.

The 1st two prototypes have been shipped, and should be here sometime next week.  Just waiting for final costing on the redesigned stacks to establish pricing.  I will of course fit one to my 550 immediately, and post pictures.

[Retro Rocket]

And report on its behaviour.....

Mick

[SF]

tintop you can put one on my bike too - firm.