to everyone with cv carbs trying to run pod filter

kzbigrick wrote: Ok age old question. Why can't I get my bike with cb carbs to run right with pos filters? Ok here is the answer and the solution to your problem. I have a kz 900 with some late model cv carbs on it (don't ask got it that way) with pod filters on it. Bike was running like shit when gave anymore than about 1/4 throttle. Started searching the net to only find the same answer "pods on cv carbs don't work". I don't like being told something won't work so I kept asking until I asked a guy that owns a local shop and this is the fix. If u look at carb there is a kinda kidney bean shaped port , well the pod filters block air flow thru this port. Cv carbs use air(suction) to raise slides. When twist throttle it opens butterfly which supplies air to motor and to carb to move slides via those ports. All u have to do is notch the rubber inside the pod that mates with port. U can pop the filter off the boot and put boot on carb so u can see where and how much to notch. I was lucky to get 2500-3000rpm out of my bike before I did this now it is running fine. U will still have to do some jetting as with any performance upgrade. I hope this post answers this age old question and saves a lot of headaches for people.

How bout some pictures to go with this, these are off a 89 suzuki katana 750, filters are k&n






This kinda makes perfect sense.. Ive been having a hard time adjusting with the pods, but im not giving up!! Just got smaller mains in today, 120's, from 130's. Whike i was doing that, i got these pics, actually seems like it makes sense. Im also wondering if this is a specific problem for the double k&n filters, and NOT for the individual ones found on ebay that are NOT k&ns? Id love to see a pic with you cv guys of the flanges and the for the people running the individual filtersm can we see a pic of the inside of the flange??

Do I need to post the link to my vintage "In search of Free lunch" tuning article again to put the "pods rule" attitude to bed in real world street garage tuning circumstances ?

www.mediafire.com/?7ttgomzmmjz

Smash & Bash BBQ at Cavanaugh Racing this weekend. BYOBS34's [as in Bring Your Own] :evil:

cavanaughracing wrote:

Marneman wrote:

cavanaughracing wrote:

Polar_Bus wrote:

kzbigrick wrote: Ok age old question. Why can't I get my bike with cb carbs to run right with pos filters? Ok here is the answer and the solution to your problem. I have a kz 900 with some late model cv carbs on it (don't ask got it that way) with pod filters on it. Bike was running like shit when gave anymore than about 1/4 throttle. Started searching the net to only find the same answer "pods on cv carbs don't work". I don't like being told something won't work so I kept asking until I asked a guy that owns a local shop and this is the fix. If u look at carb there is a kinda kidney bean shaped port , well the pod filters block air flow thru this port. Cv carbs use air(suction) to raise slides. When twist throttle it opens butterfly which supplies air to motor and to carb to move slides via those ports. All u have to do is notch the rubber inside the pod that mates with port. U can pop the filter off the boot and put boot on carb so u can see where and how much to notch. I was lucky to get 2500-3000rpm out of my bike before I did this now it is running fine. U will still have to do some jetting as with any performance upgrade. I hope this post answers this age old question and saves a lot of headaches for people.

Ive read this "fix" before. And while I do understand what the idea is, I don't believe this is the "end all" correction for why CV's simply run like garbage with pods. If this above mentioned fix was the true issue than why do the pod mfg's not advise to perform this check and or modifiy the design of the pods to ensure the carb CV vent passageway is unobstructed ? CV carbs were intoduced 21 years ago, and 21 years later most performance tuners are still scratching their heads at how to get pods and CV's to cooperate together....

Only the stupid ones :laugh: They make jet kits for CV carburetors that allow them to work properly. I've installed lots and lots of them. Factory, K&N, DynoJet....

Once you yank the airbox, it changes everything. The easiest route to a properly running bike with CV carbs is to buy the jet kit. Pissing around with larger pilots jets is the first mistake most guys make. That technique is so ancient that carburetors were measured it cubits :woohoo:

Am I dreaming???? Or did Larry C just say that there is a way to make BS34's work properly? I know, I know....burn em and get some smoothies, but for those of us on a limited budget I am curious on your thoughts (Otto, Larry, Roy) on getting the best results with the BS34's. Mine are the US made version with the fixed needles. I am curious if the Dynojet or other kits are worth the $ given that they retrofit the needle issue with adjustable ones. Any thoughts? BTW, were talking stock airbox with a k&n filter here, 4-1 Kerker.

FWIW

First, let's address this needle nonsense. What I have seen every time, in every kit I've ever installed is a DRASTICALLY different needle than the stock needle. It's far more than a stock needle with clip groves cut into it. It's precisely right there, the needle, that corrects the fuel curve for the most part.

You should have seen the original jet kit needles for an 84 900 ninja. They had to revise them because they were so short that it was possible to have them lift out of the needle jet and jam the slide open. Fortunately it's the throttle plate that controls engine speed so no accidents [to my knowledge] ever happened from that situation.

I was wrenching on bikes when the first Kawasaki's and Suzuki 4 cylinder bikes to be fitted with CV carburetors arrived at our dealership new. That was 1981 for the Kawasaki models.

At first, there were no real tuning components available for those carburetors. The norm back then was to shim the needles up with washers. Increase the main jets 4 sizes and install a larger pilot. Did that work? Sort of. It was a half ass arrangement at best. It took a lot more time than traditional mechanical throttle slide carburetors did to dial in and the results were less than stellar for all around performance.

It wasn't long before the jet kits started being produced by Dyno Jet. The kits were not always perfect but they were far better than the previous tuning method for CV carburetors with POD filters. We were very busy through the 80's installing hundreds of those kits.

What was nice about them is they allowed you to easily and fairly price a job for a customer. We established a base line price to install a kit with the base line jetting. If further tuning was required, it would be additional cost. Many kits worked quite well with the base line jetting. If anything, a needle clip position change and or main jet swap were required depending on the exhaust system used.

I've tuned many racks of CV carburetors over the years and YES they are a good carburetor for certain situations. Certainly anyone who is proficient as a mechanic can install a jet kit in CV carburetors and get a bike running reasonably well. It's not difficult.

But let's settle some total bullshit that some members here with vested interests in selling carburetor parts out the back door [so to speak] try to get people to believe.

1 - CV carburetors are NOT superior in mid range performance to a rack of smoothbores. That's such total horse shit.

2 - RS carburetors are NOT significantly superior to all CV carburetors in WFO throttle performance. That also is total horse shit.

3 - Sinking $500 into a rack of ancient CV carburetors when a brand new rack of RS Mikunis can be had for about another $150 is also total horse shit.

I don't know how many times I've said "Its the combination of parts that makes a setup good or bad" but that get's lost somehow. It's been all through history that one generation dislikes advice from the previous generation, preferring to find out on their own how to duplicate mistakes rather than learn from the previous generation. We did it too

I could site you examples where stock 34mm Kehin CVK carburetors performed within .010 SECONDS to a rack of RS34 carburetors at the drag strip. So add that up for yourself...A $100 jet kit vs what was about $500 at that point in time. But, out on the street where throttle response is king, that situation get's reversed. While the CVK's were pretty darn good, they couldn't match the midrange pull and crispness the throttle had with the RS carbs.

The problem with BS34's IMO is that guys don't understand them, don't have any money to buy a jet kit & listen to people who don't know how to properly tune them, or don't follow instructions. That last part is a major issue on forums. HENCE...endless threads of drivel with bad results most of the time.

Some of the OEM Keihin CV carbs, those prior to the CVK series were not good CV carburetors to work with when it came to pods. They were just adequate with the air box in place. They had actual air chokes rather than enrichment circuits like the Mikuni BS carbs had. That hurt their air flow characteristics. But keep in mined those carburetors were not used on Performance Models.

I can make pretty much anything work reasonably well. I'm old enough and experienced enough to be able to tell you right from the beginning if the effort is even worth considering...because I've been there..done that.

I come down hard on BS34's because IMO, guys dump way too much money into them. They're not worth it. I see posts from NADS about the cosmic orgasms he's getting from his BS34s... All I can say about that is wear a condom :laugh:

That is one long post to say that bs 34's are indeed good carbs.

That they have been known to be .010 from a set of rs's in a drag race.

Bout time you got around to sharing.

A friend's chipped and piped m109 did not have a chance against my bike.

That's a 12.2 @ 110. for the m109, not fast but it was
like he was left standing still.

I'm waiting for an r6 to roll up.

I don't have an airbox or pods so I don't know what your all
talking about.

I'd have to agree that changing around all the jets
will lead you no where.

approach with caution,
look left, look right,
no cops? got the right jets?
Hammer it !!
don't be late for work.

work needs proper jetting too.

I AM THE PILOT JET
I AM THE MAIN

otakar wrote: I have absolutely no problems and there is NO Notch inside the filter boot.

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Ditto on my kz 750 e3. Been running pods for well over a year, and only have had electrical problems with the bike. When everything electrical is working properly, she pulls hard to red line.

or you can just order the super flo filters from ape...just sayin..