Be cautious with the CNS ported intakes

Discussion in 'Spare Parts & Tools' started by Fletch, Jan 22, 2011.

  1. Fletch

    Fletch Member

    I will not say with 100% certainty that the ported intakes for the CNS from pirate cause both of these carbs to break in exactly the same place a couple days after installing them on two different intakes, on two different bikes, but I think it is highly coincidental.

    I'm not trying to badmouth them at all because they are a great company. I think that maybe this is either a fluke thing that happened with my carbs because they had been tightened down so much on the regular intakes using the white collars that come with them, or maybe it's because they are relatively new intakes, so there hasn't been that much customer feedback on them yet. Either way I think I should share my experience and let others know that there is at least a possibility this may happen. Like I said, I just think it is too coincidental to dismiss.

    It's a shame because the intakes fit great. I think that the metal of these carbs is so weak that they are just prone to breakage from vibration- also prone to vibrating off the stock intakes completely. The mouth of the carb (if that is what you call it?) is relatively short and very wide.... and the carb is heavy so that doesn't help either.

    Take a look at where they broke and notice the same pattern. My guess is that the white collar that comes wit them helps protect the carb from the direct vibration. When you remove that collar and you put all of the force (and vibration) directly on the "mouth" of the carb on that wide intake... I just think the vibration is too much for it to handle.

    Please take this FWIW... and I'd appreciate any other hypothesis as to why they both failed like this and maybe something that could be done to lessen the likelihood of it happening?

    These carbs aren't cheap and I have a whole box of broken carbs and parts possibly for sale, but that is another thread. I really like the extra torque they provide, but I would find myself adjusting the carb almost every ride.

    Attached Files:

  2. Scottybotty

    Scottybotty New Member

    It might be a good idea to Mic (Micrometer) the stock intake tube and CNS tube and see what the difference between them is. Im sure Pirate would appreciate your input. Might be a Quality control issue on one batch and they might be able to catch the problem early. Thanks for the head up, I was looking at their intake tubes the other day.
  3. Fletch

    Fletch Member

    In retrospect after having the last CNS brake on a standard intake, I think I was over-tightening them. The metal is not very strong at all, and all my carbs fractured and broke at the exact same place. I had thought that it was the lack of the plastic piece between the carb and intake that was the cause originally, but now I have my doubts. Hope that helps.
  4. rustycase

    rustycase Banned

    Fletch, I have a TIG welder...
    Do you think those broken carbs could be repaired?
  5. Fletch

    Fletch Member

    I have no idea? I don't know anything about welding.
  6. hi fletch i cant find the float height i have two new cns crabs v1 & v2 i play with them for 3 weeks i know it off topk im sorry
  7. tintor

    tintor New Member

    cns parts

    I am wondering what you are tightening carbs with,also do you still have carb parts for sale?
  8. Fletch

    Fletch Member

    sorry, didn't know about this post. You mean you can't find the correct height to set the float to? You just bend the little tab on the float that pushes up against the float needle.
  9. Fletch

    Fletch Member

    I use a screw driver. Yeah, I kind of gave up on selling that box of cns parts. I think I may have even thrown it all away. I'll check to see if I still have it all.
  10. Fletch

    Fletch Member

    BTW.... I gave up on those POS cns carbs. I would highly recommend a mikuni VM18. The only issue with it is that you have to use a short CNS intake from pirate and sand the white plastic part that goes around the intake down to fit around it. It won't fit on a regular intake. Other than that, it's the perfect carb.
  11. tintor

    tintor New Member

    I have cns can not get it dialed in correctly. spent way way too much time trying I have raced for several top motorcycle companiesfor 13years of my life,I feel my time should be used enjoying life not spent %%$#^% with a cns carb. With that said do you feel the makuni or dielorto shows better performance??
  12. Fletch

    Fletch Member

    I don't have any experience with the dellorto, just the Mikuni VM-18
  13. buzbikebklyn1

    buzbikebklyn1 New Member

    The CNS was not properly field tested, that much is certain, its a mikuni bootleg so all the tuning tricks for a mikuni will work on it, they are just so badly out of adjustment from the factory that they just don't seem to work, after careful re jetting and tuning they work very well.
    As far as breakage of the carb body is concerned, I've never had that happen with a stock GT5R intake, that looks like a downward shock caused damage.
    I still like the Dell Orto SHA series carbs.
    Ever consider a support strap? think of it as a jock strap for your carb.
    Last edited: Sep 28, 2011
  14. V 35

    V 35 Member

    Carbs are getting ' pile drivered '

    Looks like you need a way to support carb, possibly a spring from carb bowl, to engine case ? I remember motorcycles having a metal brace that bolted to carb fuel bowl screws, that must be why they were there. Some riders removed them with no consiquences.
  15. GhettoBike

    GhettoBike Member

    Yes they do
    We sell a version like this
    No breaking yet 100s sold
    2 separate aluminum pieces with gas hose link and hose clamps
    Let us know if you need any parts

  16. 45u

    45u Active Member

    I agree and is why I will be running a VM18 on my second build. Have the intake and now waiting on the carburetor to get here since the warehouse messed up and sent me the wrong thing. Here is the intake I am going to run. Shows the difference in size over stock.



  17. 45u

    45u Active Member

    You can get the Mikuni VM series clamp on carburetors off eBay for $65 shipped.
  18. 45u

    45u Active Member

    The Dellorto SHA or the SHA clone carburetor do not have a low speed adjustment. I am running a SHA Clone and they are OK but not near as tuneable as the Mikuni. On the SHA and SHA clone the only adjustments you can make is to idle speed and main jet. With the Mikuni it has a low speed adjustment, idle adjustment, you can change the mid range jet, high speed jet, the slide cut out and the needle height. If you want quality get a Mikuni and adjustability get a the real deal. It will save you a lot of headaches in the long run. Did you change the slide in it or are you running the stock slide that comes with it? From what some others have said the slide cut out needs to be changed. I all ready have some extra low and high speed jets as they all so recomend changing them. Jaguar had a really good site and one of them is about using the Mikuni.

    I deleted the link for the Mikuni as the seller is giving me the runaround.
    Last edited: Jun 17, 2016
  19. Erikinla

    Erikinla New Member

    We have an offset intake manifold as well that works really well .
    It's a three-piece kit with a vibration dampener in between a lot of complaints have come through with stock intake manifolds breaking because of vibration so we separated into three pieces to melt aluminum Barb pieces 1/5 motor side one fits carburetor side and a rubber dampener in between the two that keeps it from breaking off I agree the Mikuni's are the way to go
  20. 45u

    45u Active Member

    Does not look like a very smooth transition air flow.