kz1000m2 csr to kz1000j1 cams jetting

Hi I'm sorry if this topic is posted too much but I'm hung up on the jetting for the kz1000j model cams since in the manual they show the pilot air jets, needle jet, and jet needle as being different.
 
I just bought myself this christmas present on ebay and I can't find any information on those pilot air jets!!! They aren't even showing up in diagrams and such. My question is what's important for rejetting for these cams? Could anyone else that has done this swap chime in on what they did? I'm just looking to get more top end power out of my girl. Thanks!

Pilot air jets are to even out the stumble evident when pilot to needle jet revs are reached. They are fitted when the stock airbox has been deleted and replaced by individual pod filters. 
They wouldn't have any great effect on fueling for cam geometry that stays consistant throughout the revs range.
To shift the max bhp up the rev range carbs with a bigger throat would be required. 

That makes sense so then I'm wondering if  the jets and needles are different for the US models and other models to fit in to emission regulations? If so, would switching to the less restricted jets and needles add more power or performance?

The minor difference between any of the stock Z or J type cams ( except the 83 - 85 GPZ1100 A Unitrack ) is so slight you won't notice any performance benefits or affects on carburation..
Most jetting differences are to either account for airbox and exhaust design variations between models or emission requirements of the specific target country.

I'm going to challenge you on your claim that carburetor jettting and needles shouldn't be affected too much since in the manual its telling me to go from a 122.5 to a 127.5 main jet. If I get the sizing right, that's two sizes larger so those cams should be making a difference... that's if my intuition is correct. Feel free to call me out though cause I may be overthinking this. Im more concerned about the jet needle and needle jet because I don't have at least one of those.

On a good day the stock J was barely a couple of mph faster than the stock M.
Fitting the J cams and mucking about with the jetting isn't worth the effort for very very little or no noticeable gain.
As stated the jetting differences are mostly due to airbox and exhaust variations between models.
The cams you need for a worthwhile power increase are those from the 83 - 85 GPZ1100A Unitrack and no other model.
This is common knowledge within the KZ community..

Thank you so much,  therefore from what I understand the difference in performance of the two models is more or less similar to comparing textbook to the real world. Do you still think it would be a good idea to change to the 127.5 main jets and the 5flz50 needles? Im only asking since they came with a carb rebuild that I held onto. As always, when I get the camshaft and install it, I'll test what works best. Too bad that I don't see any of those gpz1100 camshafts around anymore. Couldn't find any on ebay. Im new to the community so I'll take your wise words. I appreciate all the help!

I have a "foot in both camps" here, with the exception of the German, Swiss and Sweden models the "J" makes around 10% more power slightly higher up the rev band (10% ain't bad for a soft tune) It looks like the "J" uses a different carb casting (two pilot air jets) but the biggest difference seems to be the main and needle jets (no idea how much of the 10% is cams and jetting and how much is air box and exhaust) As I understand it the "K & M" are a "soft tune" of the "J" spec

bound wrote:

Thank you so much,  therefore from what I understand the difference in performance of the two models is more or less similar to comparing textbook to the real world. Do you still think it would be a good idea to change to the 127.5 main jets and the 5flz50 needles? Im only asking since they came with a carb rebuild that I held onto. As always, when I get the camshaft and install it, I'll test what works best. Too bad that I don't see any of those gpz1100 camshafts around anymore. Couldn't find any on ebay. Im new to the community so I'll take your wise words. I appreciate all the help!

You should first drop in the J cams and run the M carbs as stock..
For the small difference the J cam provides i'd leave the carb needles etc alone and only increase the mains if a high speed plug chop indicates that is required.
Whatever you decide to do only change ONE thing at a time which in this case may be the mains.

Wookie if I remember correctly, aren't you running two intake cams from the J on one of your bikes? If that's right, how is that going for you? I know it won't be the same but what's your carburetion looking like? The only jet that I dont have is the needle jet. Would having a Y-1 needle jet be too different to match with the 5flz50 that's usually paired with the Y-6 needle jet or does it matter that much as stated by zed? Carburetors confuse me sometimes...

bound wrote:

Wookie if I remember correctly, aren't you running two intake cams from the J on one of your bikes? If that's right, how is that going for you? I know it won't be the same but what's your carburetion looking like? The only jet that I dont have is the needle jet. Would having a Y-1 needle jet be too different to match with the 5flz50 that's usually paired with the Y-6 needle jet or does it matter that much as stated by zed? Carburetors confuse me sometimes...

You are right that I was intending to use two "J" inlet cams in my "K" because the inlet has a little more lift than the exhaust (0.4mm) however Zed put me onto a set of 83-84 GPZ1100 cams that are the hottest factory option. My motor is probably several months away from running currently but I am also running 1075 Wiseco pistons, GPZ1100 digital ignition and a much more free flowing airbox so any comparisons would be meaningless. My plan is to install a Dynajet kit and start from there (I had good results with Dynajets in my Harris Magnum many years ago) Zed is absolutely right that you should add mods "one at a time" as it will be "trial and error" to get it right (I believe the "J" uses different carb castings so simply replicating the factory jetting may not get you where you want to be)

Bound, pertaining to the reason/function of those J carbs having (2) air jets instead of just 1. It's all because of the Coasting enricher/Air-Cut. In Honda world, because they have been using them for years, Air-Cut is more of a correct terminology because that's what they do/cut air. You'll note the location in photos their location. One at the intake, one underneath the diaphragm. You have TWO separate functions of that Air-Cut diaphragm, vacuum and metering. Vacuum pulls the little diaphragm out to "Cut-Off/Block" the air rushing in from jet underneath the slide diaphragm, resulting in a richer mixture in pilot system. High Vacuum when engine high in RPMs and throttle plate in a closed position provides this. In normal state of running you're siphoning air from Both air jets. When coming down from a stop that protrusion from air cut blocks off the upper air jet. Anyhoot, something to consider, Clay