K&N filter for VX800 - any updates ?

Hi Folks,
Seeing as the VX wasn't in production for that many years it seems to get neglected in the aftermarket parts department.
I have been wondering about fitting K&N 'replacement' filters into the stock air-box system.
K&N do not actually list an air filter for the VX800, but there are some options I have heard about that I would be interested to know if anyone out there has tried.

Option 1
I have seen an old post on another forum that says K&N part SU-0009 was made for the VX800 and the VZ800 (probably of around 1996-2000 years). I have not seen anything in manufacturers, or suppliers, listings to confirm that this part number is designated to the VX800 ..... can anyone out there confirm that ? .... or comment on if it does actually fit the VX800.

Option 1-A 
From current K&N listings I can see that part SU-5589 fits & is listed for the earlier variants of the VZ800 (With the cylindrical air filters with a flange/mounting plate on one end). That part is also listed for the GS500E, which I recall has a very similar looking air filter to the VX (As I had a GS500E in the 90's). Trawling suppliers sites, I found that the K&N SU-5589 is listed as a replacement to the SU-0009 ..... so the burning question would be has anyone out there tried a K&N SU-5589 on their VX - if so did it fit properly, or did you need to do any mods ?

Some listings suggest the VZ may need re-jetting after fitting a SU-5589, so I wonder if this may also apply to the VX800 .... any comments greatly appreciated.

Option 2
Prior to the suggestion of using SU-0009 (or the modern equivalent SU-5589) the 'trick' appeared to be to dismantle your stock air filter unit to retrieve the mounting plate, then fit a K&N universal cylindrical filter to the 'existing' air filter base. I believe the recommended filter is RU-0160. this has a jubilee clip flange to fasten it to the 'existing' air filter base. The RU-0160 is physically smaller than the SU-5589, so may have a different air flow capacity, and may preclude the need to re-jet. Any advice/comments on this route would again be appreciated.
It is interesting (For the Yorkshire men in us) that the RU-0160 option is actually cheaper in terms of filter price than the SU-5589 ..... but you do have to do the work of dismantling the existing filters etc. to retrieve the mounting plate - so what you save in money you lose in time ! .... ain't life sweet ... God moves in mysterious ways his miracles to perform etc.

Any help, comments & suggestions would be greatly appreciated.

Yam

What about this LINK

Hi Dave,

I was feeling a bit lonely on this post - & appreciate your reply.

Thanks for the link, but I think you will find these are simply a good quality pattern part for the original Suzuki filter. They would be my choice for a straight replacement of O/E kit, but I was wondering about using a K&N to optimise the induction system a little. I have used K&N type filters on a variety of vehicles in the past & find them a good purchase for long termers.

Us VXers are obviously in a minority ..... and I do intend following the K&N route up in due course. I will of course share my findings. ..... But I have another matter to attend to first ... the dreaded (occasional) clutch slip problem. Common on VZs as well I believe. I have a 'trick' to try & will report back once I've got all the bits .... waiting of clutch cover gasket .... & got to machine some bits. (Subject to finding time ... & not going out on runs - my VX is not slipping after readjusting the clutch pin last week)

There is an existing post/thread that covers this topic well, & in fairness the first point of call is proper cable adjustment and clutch pin adjustment (under side casing).

I will add my findings to the correct post once I've done my experimenting. (Whether good or bad). 
.

I just looked but K&N seemed to ignore your bike as suggested, just looked at the link above and they do say it is a HiFlow air filter but with that said we all know how the truth can often be stretched out just a little bit  

Tanks again Captain,
I actually think the term 'Hi-Flo' refers to the brand name, as I have some 'Hi-Flo' oil filters in stock ready for servicing the VX - reference HF-138, which fits a load of Suzukis. You probably know it !

As mentioned I suspect the link is for a good quality O/E replacement filter. It will not be serviceable (washable) like a K&N.

The references I quoted above are notes I made from a VX forum that I can no longer seem to access.

I was wondering if someone out there might have an old K&N catalogue/listing chart to confirm that the SU-009 was designated for the VX800 as well as the VZ. In which case the modern part might just fit.
I had however heard some problems with fit. So if nowt comes back on this posting in the next month or so - then I will probably just take the plunge & report back to all !

Thanks again for trying to assist!

Yam

This is K&N Catalog.  If you search for air filter it doesn't show they make one for the VX.
http://www.knfilters.com/search/appsearch.aspx?type=ps&year=1996&make=SUZUKI&model=VX800&engine=801

Thanks Tex,
I had scoured the current listings, I was wondering if anyone had some historical details/records to check out & confirm the SU-0009 application & if it did actually cover the VX. That would help as I believe the SU-5589 is listed as a replacement for the SU-0009.
Looks like I will have to 'suck it & see' in time ..... but I will share my findings for the benefit of others.

This is not my immediate priority .... I was doing my homework first to see if there was knowledge out there. But it is something I will look into ..... when work/spare time balance & spare cash permits !
Best wishes buddy ! ... & to Ross - our thoughts are with him
Yam

OldManYam wrote:

Tanks again Captain,
I actually think the term 'Hi-Flo' refers to the brand name, as I have some 'Hi-Flo' oil filters in stock ready for servicing the VX - reference HF-138, which fits a load of Suzukis. You probably know it !

Thanks again for trying to assist!

Yam

Bloody sods that should be out lawed, it will give people the wrong impression. Like it did me  

Hello OldManYam,
I believe the VX 800 engine is the direct swap for the VZ800 Marauder so would assume that the air filter boxes are the same,, I can confirm that the K&N drop-in part number is SU-5589.Upon checking I find different listings for HI-FLOW air filters  HFA3803 for the VZ 800 Marauder and HFA3801 for the VX 800 and it also appears that OEM filters are different so maybe  the RU-0160 is the way to go
The rule of thumb with VZ 800 Marauders is if you change the air filters only you don't have to re-jet or change exhausts only and you don't have to re-jet but change both and you do.
In the USA and I believe Australia you will read about changing the Needle and Needle jets and primary/idle jets,, some jets have to be bought and trimmed down in size ETC,, I`ve done all that and its a pain,,, English VZ800 come as standard with a 5 slot adjustable needle ( USA marauders don't ),,, on my current VZ Marauder all I did was drop the Needle clip one slot left every thing as standard apart from slightly modified standard exhaust and the improvement was very noticeable and the fuel consumption stayed the same at 53 MPG,,,, I had previously did the big needle and jet swap but couldn't get it to run right all through the rev range plus the fuel consumption was horrific. Prior to changing any jetting I serviced the bike and balked at paying £50ish each for the standard air filters so bought some after market HiFlo filters,, well the bloody bike wouldn't run at anything over 25/30 mph,, if I cracked open the throttle it breathed so well that the fuel couldn't keep up,, this lead me to doing the needle and jet swap that I loathed and swapped back to slandered.
I would like to know what you have lined up for your clutch,,,, a friend has a Sachs Roadster 800 that I believe uses the engine out of the VX 800,, he had clutch slipping problems that new friction plates and up-rated springs didn't cure ,,, he solved it by using I think it was GSX plates,, they apparently are slightly thinner than the standard clutch plates so he has managed to get an extra plate in so now has more surface area so no clutch slip.

Hi John,

Thanks for your detailed reply, which has confirmed some of my homework. I agree that the Hi-Flo air filter part numbers are HFA-3801 for the VX800 & HFA3803 for the VZ800 (1997-2004)    BUT their part ref for a GS500E air filter is HFA3501 0r HFA3503 (Depending where you look - but I'd trust the first number as the more commonly quoted one) .... so there lies the rub as the current K&N part number SU-5589 is recommended for the VZ800 & the GS500E ....i.e HFA3803 or HFA3501/3503 - so I am sure you can understand my frustration   .

My understanding is that the K&N part SU-0009 was produced by K&N (UK) ... but we are talking back in the early - late 90's. I was wondering if anyone had any 'historic' listings from that period. I understand that the SU-0009 was listed for the VX800 & VZ800 .... but am seeking confirmation of that. (i.e if anyone has it in black & white). I have seen current references that K&N [part SU-5589 is a replacement for the SU-0009, & ultimately it is likely to be my first choice when I take the plunge.

As I'm not in a rush I thought I'd do a post to see if I can firm up the information I have to assist my choice (Before I go & stab the piggy bank).
I appreciate your comments regarding jetting - & like it that UK bikes get tamperable carbs   .
I am aware of the lifting up the needles a groove & take on board your helpful comments.

I will feed back my findings in due course - but don't hold yer breath ! (Too much work & not enough 'tinker time')

As for clutch issues - I will deal with that on a separate post - mine is an occasional issue & not persistent - my last clutch pin adjustment seems to have sorted it - but I will be pulling my clutch down as soon as I get a side casing gasket as I suspect the plates may be glazed.

I know the Sachs 805 - I nearly bought one last year but ran out of garage space ! (I'd just got the VX so yet another bike would seem inappropriate according to the Paymaster General) 

Cheers    Yam

Hi Yam,
Would detailed measurements of a VZ800 Marauder air filter for cross reference of your VX800 air filter be of any help to you, if you know if your filter is the same physical size/ diameter/ intake throat diameter/mounting holes PCD (important bit) ETC as the VZ`s then it must fit in your air box so the VZ`s K&N SU-5589 should also fit,, I have a couple of new Hi-flo filters I could measure.
As for the part number anomalies some times there is mm differences in length ETC so the manufacturers give separate numbers but the biggest gip parts manufacturers do is to give different part numbers for vehicle specific items, so we, Joe Blogs, cannot cross reference for ourselves, and find that parts for a more popular model are cheaper than for our rarer model and buy the cheaper option, I recall buying a  citron van clutch for a Peugeot van and it was exactly the same clutch, same box, same manufacturers build code but different part code number but was £120 cheaper.

Hi John,
That sounds a logical next step. I will whip one of my filters out & measure them up & get back to you. This will be the first time I've took an air filter out of the VX (Only acquired it July 2013) .... I'm just thinking as I type, that I could have a red face if I now found a previous owner had fitted K&Ns !  

But I doubt such good fortune as the induction noise is not throaty.

I will have a tinker in the morning

Cheers   Yam

Hi John, & any other interested parties,

I've done some measuring & further research as follows :-

I removed one of the air filters on my VX (The rear one as it can be done without removing the tank). My 'red faced fear' did not come to light as this filter appeared to be a genuine Suzuki part  with the reference number 13780-05A00 stamped on the outside face of the metal end cap - that sits innermost in the plastic moulded chamber for the air filter.

I researched this number & found a Suzuki note indicating that this filter has been superseded with part number 13780-01D00. This note was referring to the Suzuki Madura which was a V-4 cruiser available in 1200cc & 700cc variants.

Now I know that Suzuki part number 13780-01D00 fits the GS500E, and the cross referencing for K&N filter SU-5589 includes the reference for part number 13780-01D00 - thereby suggesting it should physically fit. But to me that is only a confirmation that the flange & the holes therein will mate up. This is a step in the right direction - but has opened up a new 'line of enquiry' in my sceptical mind - which I will share in a moment. But lets deal with measurements of my existing filter first, in case it helps others.

My filter has a round casing of 84mm diameter and a depth of 106mm from mounting flange face to metal end cap. There are 4 eqi-spaced holes at 110mm PCD - that is close to 78mm measured 'between centres as a 'square pattern' group of screws (That should make sense if you are measuring the item).
The metal mounting plate has an external flange protruding 11mm which is 50mm outside diameter. This is the inlet port of the air filter to which a rubber type elbow on the VX800 is fitted to form an oval intake port at 90 degrees to the face of the filter. That 'elbow' has a single flute, or web, dividing the inlet oval, which to me looks like a flow design consideration (or could be to stop the oval flattening inwards during heavy induction which would lower area/volume of the inlet aperture and could cause problems ! - which is still a flow consideration in my mind !) The 'elbow' is covered by the side panel on the bike so air is drawn into that rear carb from the area below the seat and the side panel - just in front of the rear wheel.

Now - the inlet port on the mounting plate of the replaceable filter element has an internal flange, which appears to be formed from a separate metal tube/pressing. The total length of the metal inlet tract is 40mm, but the internal flange appears to be swaged down to a smaller diameter (approx. 36mm inside diameter) So the inner bit of tube is approaching 29mm long  
So now I'm getting somewhere - I believe the K&N part SU-5589 should physically bolt onto the standard air box - in place of the standard filter - it does not have the external flange to which the 'elbow is fitted. Also the moulded rubberised flange of the K&N filter is thicker than the pressed metal flange on the O/E type filters so you will need longer screws to mount & fix the K&N filters (From the SU-5589 installation instructions that can be downloaded from the K&N website it sounds like their filters are supplied with longer screws - but thought it worth highlighting for the benefit of others).

So now I need to consider do I want to lose that 'elbow' or not. I suspect the induction noise would be higher without the elbow in place, but I wonder if the elbow may have some tangible benefit to the induction flow.
I am also aware that the SU-5589 has an insert for the inlet, which is effectively a reducer. This is used on the GS500e & omitted for the VZ800. But I don't have details of the relative inlet sizes (diameters) with or without the reducer.
The K&N website indicates the SU-5589 is 127mm long - so I need to check if the air filter box can accommodate that length (With my existing filter only being 106mm long).
The RU-0160 is quoted as being 102mm long, but that is not clear as to whether it is overall length Which I expect, or filter length (excluding flange). If it is overall length then when mounted on an existing filter metal mounting flange the length inside the filter housing could be 29mm + 102mm - 16mm mounting flange = 115mm .... or if it was filter body only it would be 131mm
I suppose if the K&N could be persuaded to fit over the 'fatter' portion of the swaged internal pipe, then it would drop the protruding filter length to 102mm (or 118mm if we have to add the mounting flange length)

So I am getting nearer to a decision - but it would be prudent check if the existing filter box can accommodate the extra depth (if needed). I will do some check on this at a later time.

I must admit that having looked at the set-up in more detail, I think I would be tempted to keep the elbows ..... this is likely to be possible with SU-5589 as you could fit a retrieved metal mounting flange from a discarded O/E filter over the K&N like a big washer, BUT if you are retaining a retrieved metal mounting flange then the RU-0160 is a more cost effective option as they are £10-12 cheaper (each) than the SU-5589.

It would appear that retaining the 'elbows' would also be an issue on the VZ800 - certainly the chain drive versions, in which case by using the SU-5589 as supplied you would loose the elbows, which may lead to loud induction noises form parts of your bike - which I think an owner has mentioned on another post elsewhere. If that is the case the use of the RU-0160 could be a workable option for VZ owners if suitable cross-referencing is done to the existing filter, and air-box casing.

I would remain interested on any feedback on any of the above.

Cheers - Yam

Hi again to any interested parties !

I've just been tinkering again ..... I made up some spacers (from supermarket polystyrene pizza bases if you must know) the same diameter of the air filter and progressively added & subtracted them to the inner end of the original air filter to see how much clearance there was in the VX800's rear air filter box. The filters were taped & rubber banded onto the O/E air filter. This is a static fit test - No engine running was done - thought it best to mention that.



From this I concluded there was a safe 121mm clearance from the mating face of the mounting flange to the inner end of the air filter.

That rules out using the K&N SU-5589 as it is stated as being 127mm long. From this I suspect that the older SU-0009 may have been shorter, and whilst the SU-5589 is said to replace the SU-0009, it may explain why K&N don't actually list an air filter for the VX800. ..... The SU-5589 won't physically fit into the airbox !

From this it is fair to conclude that the only viable K&N option to try for the VX800 would be the RU-0160 mounted onto a stock mounting flange recovered from a discarded O/E spec air filter.

So there is the answer .... all homework done .... just got to stab the piggy bank at a time when I have a bit of spare time to tinker with the bike.

I will confirm if the installation is possible once I've taken the plunge. Thanks to those members who have offered assistance - I remain open to comments & suggestions. (I had worked out that if I got the SU-5589s & found they did not fit properly I could swap the VX for a VZ !) ... too easy !

Cheers    Yam

Bloody interesting, I love to see stuff like this. This is what for makes modifying fun, the trial & error plus the feel good factor of being the man that can and is prepared for trial & error.  

Yes Dave,
I agree, it helps illustrate what can be done from thinking & researching before your start actually buying & fitting parts. This type of trial fitting only costs you time & saves the embarrassment of buying parts that just won't fit.

What I've done in this little exercise is something almost any of us forum members could do if they put their minds to it. I have done similar exercises in the past, but I found that by posting this message string I was encouraged by the interest & suggestions of others. I guess you will have found that out yourself in some of your posts.
Regards
Yam

The thing is that threads like this are to an extent immortal & we will be gone a long time before the inspiration for others has gone because the thread will live on. I converted a K&N filter to fit in the stock C/VL800 box years before K&N decided to make one to fit the later models, which they only did recently. Sometime we may get nowhere with what we do and other times we will but what we are doing is allowing others to learn by our mistakes, successes & draw ideas from our own. I still have so many planned things to do to my bike & in good time (when properly upto it) will start again.
I have already drawn inspiration from you and and others and giving me new ideas, keep up the great work, your an inspiration.

Thanks for the kind comments Dave,
I guess from other threads you've been through a bad patch & are in a recuperation stage. I know what that's like, & the value of buddies & the forum site to give you inspiration to get back to where you want to be. Hang on in there, we are all rootin' for you.

I very much agree that the forum becomes a good source of information for others, and we all learn from each other & it reinforces some of the points covered in the 'proper biker' thread. 

Cheers buddy - you take care. I'm off to work now !
Yam

I gotta agree with all said from the last few posts, lots of you guys make us not so capable types have ago at stuff we would not of dreamed of if we couldnt see on site what you guys love doing and how you do it.

Back to the filter
I do not know a lot about this sort of stuff but wonder if you could buy a high flowing filter foam and go that way instead by cutting it to fit :what1:

captain crash wrote:

I do not know a lot about this sort of stuff but wonder if you could buy a high flowing filter foam and go that way instead by cutting it to fit :what1:

Sounds like a very viable plan to me.  

Hi Captain,
Not sure if you were thinking of sourcing something for your own bike or not, but for the benefit of anyone looking for a high flowing air filter I would say - Have you checked the K&N website to see if they list a 'direct replacement' unit for your bike .... try :-
www.knfilters.co.uk/search/appsearch.aspx 

I know they do for a lot of the current bikes (i.e. VZ variants) ...... my problem is my VX is in its 18th year & was one of the 'last' production years - so they don't cater for us with older bikes.

Whilst the route I've described above sounds like a lot of messing, when you have a standard air filter in your hand, it is easier to see (& understand), and it should not be too big a job to 'retrieve' the metal mounting flange from a standard air filter. You would just need to work carefully - the 'think twice before cutting' motto would help.


There are other air filters such as S&B or DNA that offer similar enhance flow performance - but as mentioned in this thread there is a manufacturer called 'Hi-Flo' which is just a decent quality O/E spec  standard type filter.

Cheers      Yam

Hope I didnt come across wrong, I was looking at options as your thread got me thinking, not a good thing for me to do I know.    I did not mean to take anything away from what you were saying as your writeup is very interesting  

Hi Captain,
No worries, I don't mind any comments - I was just trying to offer a 'route of thinking' for anyone contemplating the High Flow filter route. You suggestion was totally valid .... & it is best to keep 'open minded' ...... as my old structural mechanics lecturer used to say .... There are many ways to kill a pig .... you don't have to choke it with strawberries !  (i.e. the way I was describing might not be the 'best' way).
I guess by now, & from some of my other posts, you will realise I am 'open minded' !

Cheers    Yam

Hello Yam,,
I am so sorry I haven't replied to you but I was suddenly side-lined for a week but I`m back home now. I`m going to put some pics up for you to look at,,i got out and looked at a genuine VZ800 air filter that came new factory fitted with my VZ ( Sadly going to have to sell it soon as I cannot afford two bikes) and also a free-flo aftermarket air filter bought again for my VZ,,, I had a quick measure of the original filter and the measurements meet the measurements of your VX filter,,,
The web in the inlet elbow snorkel is to restrict airflow.
The VZ800 runs just on the boarder of running weak,, it was designed this way for Suzuki to meet the strict emission laws in America,,, if I remember correctly Suzuki had 4 bikes in the cruiser stable at the beginning ,,,Intruder ,, Volusia .,,Marauder,,, Boulevard.
The intruder was first and Suzuki made it to suit the current ( at the time ) emission laws but by the time they got round to doing the VZ Marauder ( it was supposed to be the muscle bike version in the cruiser stable) the emission laws had changed and Suzuki were forced to strangle the Marauder to get it to meet the new emission laws,,, this is why many people re-jet the VZ and get useful gains in performance,,, personnel I have re-jet 3 VZ`s but fuel consumption took big nose dive so my VZ now runs stock except for clips on the main jet needle dropped one groove ( you feel the power change and smother response and fuel consumption stays at 53mph normal use). As your VX uses the same engine I suspect that your bike will have its air flow restricted also ( as you say you have the intake snorkel restrictions and the filter throat restrictions ). When I did a stage 3 re-jet on one VZ the inlet snorkels are removed,,, I didn't notice any difference in induction noise at all,,, the only down side I found is that the front filter, because it breathes just behind the headstock frame cover, sucks in water if caught out/ ride in the rain.
In standard trim my VZ will not run very well at all with the after market filters shown in the pic`s,,, far to much air is available and the main jets/secondary cannot keep up with demand when the engine is worked and power drops of a sodding great cliff at anything past about 30 MPH,,, it runs reasonable ok when at low rev`s when running on primary jets,,, so if your bike is the same and you do use an after market/K&N filter I think you will have to re-jet and you will have to re-jet if you remove the air-box snorkels.



VZ front intake snorkel number 8


Original filter


original



original


AFTERMARKET


aftermarket



Both


Both


Both



Original Throat Restriction

NOW THE REALY GOOD BIT,,, I CHECKED THE LABELS ON AN ORIGINAL SUZUKI VZ FILTER BOX AND AFTERRMARKET FILTER BOX AND LOW AND BEHOLD THE AFTER MARKET FILTER WICH WAS ADVERTIZED AND BOUGHT FOR THE VZ AND IS THE SAME SIZE  AND DIMENSION AS THE ORIGINAL, APART FROM THE THROAT RESTRICTION IN THE ORIGINAL AND FREE FLOWING THROAT IN THE AFTERMARKET, IS MARKED ON THE BOX AS FOR A VX,,, SO WITH THAT MATE I THINK WE CAN SAFELY SAY THAT THE K&N FILTER FOR THE VZ WILL FIT DIRECTLY IN TH VX


Suzuki part VZ 800 air filter


After market air filter bought for and fits VZ800 marked for VX 800


aftermarket box


After market box

Hope this is of some help to you mate.

Excellent detective work John.    

Hi John,

Thanks for your detailed reply - it ties in a lot of the assumptions I've made.

The line drawing for the VZ air-box is similar to that of the VX, so I would not be surprised if they are the same parts.

From our measurements it appears the mounting flange is identical - as confiremed with your parts markings on your pictures - but the depth of the air filter from the mounting flange remains a concern to me as the K&N (SU-5589) one is quoted as being 127mm long - now that could be including the flange thickness, in which case it might then fit.

There are potentially two schools of thought in how the induction system flows. It all depends on whether you look at certain fittings in the induction system as 'obstructions' or 'designed' components.
This is a similar issue to some 'free flowing' exhausts not always working as we might expect - though admittedly this could also be a jetting issue after replacing 'stock' parts.  

The whole induction system is quite complex with the filters being 'remote' from the carbs and the VX has a balancing tube between the two air filter boxes. I'm not that sure the web in the elbow is there as a restrictor due to its small cross sectional size, I suspect it is to stop the rubberised elbow collapsing in on itself at high air flows. The elbow itself may be a 'restrictor', or a flow diverter. Same with the pattern filter with the open throat - the reduced throat of the O/E filter might actually be designed to stop a vortex problem as air enters the air filter. The only way to see is via a flow bench - & I don't have access to such equipment. This does cloud the issue as if the throat restrictor is a form of vortex control, I would loose that benefit if a went the K&N RU-0160 route (Which is currently my favoured option).

Interestingly on the 'restrictor' or 'designed' component concept - I fitted a K&N on a CBR600F and it comes with a modified flow deflector screen that 'has' to be used in the installation. This is physically a vertical plate that sits between the air entry points & the air filter & 'common sense' would suggest it is a 'restrictor', but it is actually needed as it is a 'designed' component.

Any way up, I am not expecting any significant performance increase by just changing to a K&N filter, its just that I've used them a lot in the past & I though that when I do get around to changing the air filters on the VX it would be worth considering K&Ns.

What I am tempted to ask forum members with a VZ or VX, is do they have any discarded air filters so that I could pre-prep a mounting flange for a K&N conversion ... as my current air filters are serviceable & I don't really want to chop into them to find the K&N route is not to my satisfaction, & then I have to buy a replacement O/E spec filter to replace the good one I'd chopped up !!!!!
(i.e I don't want to end up putting my VX off the road due to experimental chaos). 

This one will probably keep rolling till I take the plunge.

Thanks to all of you who are assisting my enquiries - it is appreciated. - Yam

Hello Yam,
From the mounting face of the genuine filter to the base is 106 mm,, I have fitted K&N`s into VZ air boxes and as we have seen the VX`s air filter is the same size so that leads us to K&N filter for a VZ fitting into the air box ( oooooh that sounds very rude snigger snigger) of a VX.
In the past when trying to tune VZ`s for more power on a very tight budget ( just enough for a beer and a packet of crisps whilst tinkering) I tried increasing air flow by cutting out the web in the inlet snorkel,, they don't collapse but the bike didn't run to well as on more aggressive throttle/ higher engine demands not enough fuel ( like I said they are on the edge mixture wise ) ran it like this for about 500 miles whilst tinkering with the jet  adjustments and balancing the carps to try and getting it to run smoother,, eventually  re-manufacturing the web with old inner tube cured it again. the diverting issue I think is purely to control intake I.E to stop rain/water intake,,, when it happened to me the front cylinder would cough and fart and lose power
One fairly common Mod when putting larger Jets in was to put a hole saw down the middle of the original air filter to remove the restrictor improving/increasing air flow so alleviating the need to buy high -flo or K&N  filters.
I think K&N would have taken all this into account when making filter and as you said with the CBR they would supplied any diverter plate if needed.
Trying to find some old proper old school type photo's I had when I stage 3`d my second VZ, I used K&N`s don't re-call any additional diverter plates being added,,, stage 3 uses a drop in free-flo filter of some description most people use K&N fitted in the original air box,,, some people have "stage 4`d" there VZ`s including removing the air boxes and fitting K&N cone filters straight onto the carbs and High lift cams.
 Happy tinkering Mate
 
John

Hi John,

Thanks again for your detailed reply, I can see you have done a great deal on the VZ induction system, & some of the other mods sound good too.

Yes the diverter plate I mentioned is unique to the CBR's airbox. The current K&N (SU-5598) for the VZ has a 'restrictor' type device for reducing the opening for use with the GS500E. I would not expect a diverter plate to be used in the VZ/VX type air-box.
It seems that we have the same length stock (O/E) air filters (!06mm), and you have fitted the designated K&N to your VZ, so that should mean it will fit the VX .... which again leads me to think the quoted K&N filter length for the SU-5589 is the overall length, so the flange thickness is included.
mmmmm - its got me thinking. I was originally going to mail order some K&Ns, but I might see if I can find a fairly local stockist so that I can look at one 'in the flesh' so to speak.
don't worry - I'll get there .... eventually.  
Thanks again    Yam

What an excellent thread, great information there guys.  

Hey Yam, I think you should just leave the pizza base, rubber band and packaging tape exposed and go for the rat look!

Only joking... Great thread, and some very very informed detective work all round.  

Hi Tomacast,
Yep thanks for that - I've looked your article up on the VX forum .... (I'd misplaced my password, but got it re-set).

For the benefit of others, Tomacast used universal K&N pods that did away with the standard air filter boxes and coupled into the 'trunking' that feeds from the filterboxes. The K&N part numbers used are :-

http://vx800forum.com/forum/index.php?action=dlattach;topic=20.0;attach=1718;image
The front is F025A4



http://vx800forum.com/forum/index.php?action=dlattach;topic=20.0;attach=1719;image

The rear is F021A4

This is clearly a useful solution, but as Tomacast clearly states will require time re-jetting etc. Which does not surprise me because this is a significant change to the air induction system.

It goes back to an earlier part of the thread, in that some components are 'designed' for specific purposes as part of the air induction process. for example there is a duct/pipe connecting both air filter boxes on the standard bike. If you remove that it effects how the bike rides. I'm afraid there is more to this topic than just saying I've put a high flow filter on and now my engine cannot cope with the high air flow, and the standard induction system is not as 'restrictive' as many people think. Real term % gains from air filter mods are quite small.

I am not looking at K&Ns as an option to give me more power, or expect it to yield a significant tangible difference in the way my bike rides, my primary consideration was to used them as a fit & forget maintenance item .... as they flow well & are serviceable (Can be cleaned). I've used K&Ns on many of my vehicles over the years.

I've still not had time to progress with sourcing K&N's, but will feed back when I do. I am interested in retaining the 'stock' induction system as I think this will actually give the best 'on road' performance. I will update my findings when I gat around to the next stage    Yam