VM26 (clone) vs PZ30 help

[Wancsta]

Has anyone that has done the swap actually measured the inner bore diameter on both carbs? Both are supposed to be 30mm. I'm just wondering if there's even a minute performance gain to be had by removing a perfectly good running PZ30. Tuning and butterfly chokes being the same the only difference could be inner bore diameter. So if anyone is in the middle of doing a swap or has both on hand could you please take a quick measurement?

[Megadan]

Has anyone that has done the swap actually measured the inner bore diameter on both carbs? Both are supposed to be 30mm. I'm just wondering if there's even a minute performance gain to be had by removing a perfectly good running PZ30. Tuning and butterfly chokes being the same the only difference could be inner bore diameter. So if anyone is in the middle of doing a swap or has both on hand could you please take a quick measurement?

Its not done for performance. Its because mikuni jets are easier to come by.

[Wancsta]

I had tried searching and with all these swaps I was surprised to see no one ever did a side by side shot or at least a quick measurement.

[enforcer89]

Heres my finds my vm26 and jets I ordered came fast the jets I ordered off amazon fit both my stock carb off hawk and the vm26 . I put a 115 main jet in both and swapped back and forth the only gain I had was the vm26 idled a bit better off a cold start than stock carb .

[Rangerscott]

For the knock off keihen carbs, just have to search ebay "gy6 jets."

[Wancsta]

Look in the Tech Favorites at the top of the dual sport index. PZ30 VS Mikuni carb comparison with pictures.

Thank you exactly what I was looking for!

[Ariel Red Hunter]

Has anyone that has done the swap actually measured the inner bore diameter on both carbs? Both are supposed to be 30mm. I'm just wondering if there's even a minute performance gain to be had by removing a perfectly good running PZ30. Tuning and butterfly chokes being the same the only difference could be inner bore diameter. So if anyone is in the middle of doing a swap or has both on hand could you please take a quick measurement?If you have a perfectly good running PZ30, you are very lucky and there is no point in changing to a Mikuni. If you go to an after market exhaust system and/or open up the air box, you might want to change...ARH

[Megadan]

Heres my finds my vm26 and jets I ordered came fast the jets I ordered off amazon fit both my stock carb off hawk and the vm26 . I put a 115 main jet in both and swapped back and forth the only gain I had was the vm26 idled a bit better off a cold start than stock carb .

The problem isn't the main jets with the PZ30, it's the pilot jet/slow jet that is the problem. Also, the needle has no adjustability to it, so washers have to be stacked.

Just to sate your curiosity, I measured both carbs with my calipers. Stock PZ30 at manifold - 29.92mm. Mikuni VM26 "30mm" 29.87, with a small margin of error granted because there is no clean edge for my calipers to grasp. So, in short, they are both 30mm. I will note that the stock carb throat is actually not centered in the body on mine, and it sits lower than the inlet manifold port a little, the VM26 I ordered centers up perfectly.

[Wancsta]

The problem isn't the main jets with the PZ30, it's the pilot jet/slow jet that is the problem. Also, the needle has no adjustability to it, so washers have to be stacked.

Just to sate your curiosity, I measured both carbs with my calipers. Stock PZ30 at manifold - 29.92mm. Mikuni VM26 "30mm" 29.87, with a small margin of error granted because there is no clean edge for my calipers to grasp. So, in short, they are both 30mm. I will note that the stock carb throat is actually not centered in the body on mine, and it sits lower than the inlet manifold port a little, the VM26 I ordered centers up perfectly.

Thank you for the confirmation. I am completely happy with my pz30 at least for now. I have an eBay exhaust waiting to go on once I get a minute. Even so I am no stranger to drilling jets and have a micro hand drill set exactly for that already.

I did notice in the tech info thread about the carb throat and wasn't sure if maybe that was specifically matched to our manifolds? Or is it just the design? If that were the case I would suspect the mikuni would actually be a slight downgrade (performance wise) if it was not smoothed out in that area.

[Megadan]

I did notice in the tech info thread about the carb throat and wasn't sure if maybe that was specifically matched to our manifolds? Or is it just the design? If that were the case I would suspect the mikuni would actually be a slight downgrade (performance wise) if it was not smoothed out in that area.

I checked both. I had the intake manifold off too, and decided to see the alignment because of this very same thought. Mikuni lined up perfectly, PZ30 did not.

[Wancsta]

I checked both. I had the intake manifold off too, and decided to see the alignment because of this very same thought. Mikuni lined up perfectly, PZ30 did not.

Nice! Was there enough material there to hog it out a little?

[Megadan]

Nice! Was there enough material there to hog it out a little?

Maybe a tiny bit, but there is no way to know how thick the inner metal sleeve is on that intake manifold.

[Wancsta]

Maybe a tiny bit, but there is no way to know how thick the inner metal sleeve is on that intake manifold.

Ok thanks probably not worth the hassle.

[Shaliza]

Heres my finds my vm26 and jets I ordered came fast the jets I ordered off amazon fit both my stock carb off hawk and the vm26 . I put a 115 main jet in both and swapped back and forth the only gain I had was the vm26 idled a bit better off a cold start than stock carb .

I bought a VM26 mikuni clone and jets for it off of Amazon for my Magician 250, and for some reason, the mikuni jets would not fit the VM26 carb but they would fit the stock Sheng Wey PZ30 carb. See pic below: the jet on the right came in the VM26 carb. The one on the left is the 110 jet that would not fit in the mikuni carb.

Did anyone have this problem or did I receive a wrong product?

Edit: By "not fit" I mean, it would get tight after a few turns and not fully seat.

10206

[hertz9753]

I bought the same set of jets and had the same problem. I wrote something about not buying the buying the Wings jets if you will be using the Mikuni clone.

[humanbeing]

The pic showed it won't works from day 1. It don't matches ANY pics from Jetsrus/ others that sold cheap copies
[Typical chinese]
PZ30 (aka Keihin clone)
http://gd3.alicdn.com/imgextra/i2/77787886/TB25i9CiSFjpuFjSspbXXXagVXa_!!77787886.jpg_400x400 .jpg
Mikuni
http://gd1.alicdn.com/imgextra/i1/77787886/TB2wdYRk7qvpuFjSZFhXXaOgXXa_!!77787886.jpg_400x400 .jpg

[Megadan]

Funny, they work perfectly in my mikuni clone.

[Shaliza]

I bought the same set of jets and had the same problem. I wrote something about not buying the buying the Wings jets if you will be using the Mikuni clone.

So which jets do you recommend if I want to upgrade the jet in my Mikuni clone?

Also I wonder why many people (Megadan and many other people who reviewed on the Wings jet on amazon) were able to install it in their Mikuni clone :hmm:

[Megadan]

The funny thing is, just out of curiosity, I went and tried to screw one of the jets I got from Wingsmoto into my stock PZ30 and it gets tight after a couple of turns. Yet on my VM26 clone, they screw right in with no trouble. My 110 main is a Wingsmoto main jet.

I then dug into my Bag-O-Jets and fished out the 100 main that came in the VM26 and compared it to the rest of my Wings jets... same threads. My PZ30's 98 main jet on the other hand is every so slightly different.

So I can only assume that Wingsmoto is packaging and selling both types of jet as the same thing, or there was a mix up somewhere along the distribution chain. It wouldn't be surprising.

[Megadan]

The pic showed it won't works from day 1. It don't matches ANY pics from Jetsrus/ others that sold cheap copies
[Typical chinese]
PZ30 (aka Keihin clone)
http://gd3.alicdn.com/imgextra/i2/77787886/TB25i9CiSFjpuFjSspbXXXagVXa_!!77787886.jpg_400x400 .jpg
Mikuni
http://gd1.alicdn.com/imgextra/i1/77787886/TB2wdYRk7qvpuFjSZFhXXaOgXXa_!!77787886.jpg_400x400 .jpg

Technically, the Mikuni Jets you have listed are the wrong ones for the VM26 clone. At least the one I purchased. they have the same thread type, but the VM26 uses N100.604 jets, aka "large round" which are an 8mm width head, the ones you have pictured are N102.221 jets.

The Keihin jets, also known as #99101-393, are so close in thread diameter and pitch that they NEARLY work, which is why I honestly think somebody somewhere is either selling both as the "same thing" to cut costs, or there is some sort of mix up happening somewhere. I do know that the stock main jet in my Hawks factory carburetor has the head diameter of a Mikuni N100.604 (8mm). Which means it has the Mikuni jet head, and Keihin M5x.8 thread.

Having a .05 difference in thread pitch would explain why the threads get tight. For shits and giggles I went ahead and tightened the stock VM26 main jet all the way into the PZ30. I then backed it out. No thread damage...although I wouldn't recommend doing this, it will work.

[hertz9753]

So which jets do you recommend if I want to upgrade the jet in my Mikuni clone?

Also I wonder why many people (Megadan and many other people who reviewed on the Wings jet on amazon) were able to install it in their Mikuni clone :hmm:

I ordered Mikuni VM28 pilot and main jets. I will give the numbers later after a long shift of sleeping.

[Megadan]

Mikuni VM26 Clone.
Pilot Jet = VM28/486 http://www.jetsrus.com/a_jets_by_carburetor_type/jets_mikuni_VM28-486_pilot.htm
Main Jet = N100.604
http://www.jetsrus.com/a_jets_by_carburetor_type/jets_mikuni_N100-604_main_Large_round.htm

Obviously elevation and modifications make a difference in what sizes you need for each. A lot of people run between a 27.5 and 35 pilot jet

Main jet size can range anywhere from the 100 main jet that comes in the Minkuni if you are at high altitude on a stock bike. I am at 1000ft elevation with a 110 main on an otherwise unmodified bike. With exhaust and intake mods, 115 to 120 jets are the most common, and I think I have seen one or two examples running a 125.

For what its worth, while it may be more expensive, I would recommend getting the genuine Mikuni jets. The reason people opt for the Wingsmoto jets is that you get 10 jets for less than the cost of 2 genuine jets.

[Shaliza]

Thanks for the information. I just ordered 110 main (N100.604). I should receive it in a few days and report back.

[Megadan]

Thanks for the information. I just ordered 110 main (N100.604). I should receive it in a few days and report back.

You will likely need to get a larger pilot jet as well. The mikuni clones come with a 20 pilot, which the bike will run on, but might be a bit too lean. If you can't manage to get a steady idle or you get some hesitation/stuttering while holding a light steady throttle at say 20-25mph with no more than 2 1/2 turns out on the mixture screw, then you will want to go up in pilot jet size. I have a 30 pilot jet and I get the slightest bit of hesitation at light throttle, so I have a 32.5 and 35 Pilot jet on order to try out.

[Hawk 229cc]

You will likely need to get a larger pilot jet as well. The mikuni clones come with a 20 pilot, which the bike will run on, but might be a bit too lean. If you can't manage to get a steady idle or you get some hesitation/stuttering while holding a light steady throttle at say 20-25mph with no more than 2 1/2 turns out on the mixture screw, then you will want to go up in pilot jet size. I have a 30 pilot jet and I get the slightest bit of hesitation at light throttle, so I have a 32.5 and 35 Pilot jet on order to try out.

Hi Dan ,i got my mikuni on order says japan of the side of it ,$38.00 i got the wings jet kit as well with 25 pilot i wonder how the 32.5 or 35 worked for you or if you stayed with the 30.i am at 1010 feet so seems the 110 ,will work should i get the 30 or higher thank you .just a note i seen pz30 carbs saying vm26 ,after reading the whole thread pz30 is the stock carb ?? so i was just a bit confused when i bought my carb ,ebay has sellers saying pz30 vm26 mikuni ,but stayed away from that one,think i am going to get the 30 32.5 an the 35 an have them

[Ariel Red Hunter]

Mikuni VM26 Clone.
Pilot Jet = VM28/486 http://www.jetsrus.com/a_jets_by_carburetor_type/jets_mikuni_VM28-486_pilot.htm
Main Jet = N100.604
http://www.jetsrus.com/a_jets_by_carburetor_type/jets_mikuni_N100-604_main_Large_round.htm

Obviously elevation and modifications make a difference in what sizes you need for each. A lot of people run between a 27.5 and 35 pilot jet

Main jet size can range anywhere from the 100 main jet that comes in the Minkuni if you are at high altitude on a stock bike. I am at 1000ft elevation with a 110 main on an otherwise unmodified bike. With exhaust and intake mods, 115 to 120 jets are the most common, and I think I have seen one or two examples running a 125.

For what its worth, while it may be more expensive, I would recommend getting the genuine Mikuni jets. The reason people opt for the Wingsmoto jets is that you get 10 jets for less than the cost of 2 genuine jets.I would like to add to this, if I may. The reason Genuine Mikuni jets cost more is because they are flow tested before being released for sale. If this is one's first foray into carburetor tuning, having the knowledge that if you put a jet in the carb it will exactly be what it says it is I think is a big advantage. This whole carb tuning issue can be very confusing your first few trips around the barn...ARH :)

[Hawk 229cc]

i am just going to get like said the 25 30 32.5 & 35 an one of those should work ,try to find my info as needed on net or hear ,but when not sure still waiting to see what he had put in his at 1000 feet sound like the 30 an 110 or 115 should work for me,with aftermaket exhuast ,i think i am just going to get one ,but note they all turn black or rust at some point,though i avoid rain myself 20 miles a day is my plan on no rainy days ,till i get it upgraded ,i also have a friend who is good with carbs does help me too,but its time i know this carb much better then ever,mights well know the bike in an out ,over time the forum is big help too,just after the 4th going to do most of the important upgrades an learn as much about the bike as i can

[Megadan]

i am just going to get like said the 25 30 32.5 & 35 an one of those should work ,try to find my info as needed on net or hear ,but when not sure still waiting to see what he had put in his at 1000 feet sound like the 30 an 110 or 115 should work for me,with aftermaket exhuast ,i think i am just going to get one ,but note they all turn black or rust at some point,though i avoid rain myself 20 miles a day is my plan on no rainy days ,till i get it upgraded ,i also have a friend who is good with carbs does help me too,but its time i know this carb much better then ever,mights well know the bike in an out ,over time the forum is big help too,just after the 4th going to do most of the important upgrades an learn as much about the bike as i can

Personally, I would get the following sizes for a Hawk with a VM26.

Pilot. 25, 27.5, 30
Main:105, 107.5, 110, 112.5, 115, 117.5, 120

This range of jet sizes would cover and fine tune everything from completely stock on a hot day to cold temperatures on a bike with full bolt ons.

[Hawk 229cc]

the only one i did not get was the 27.5 at 1010 feet ,an you has said you were going to try a 32.5 an or 35,in the thread ,did you change your mind,at this point i would think the 30 would work pretty good going to go with aftermarket exhaust from crf230 ,an i am going with a real mikuni carb the only thing is the wings jets kit ,worst case i buy 27.5 but i got a better deal on shipping to buy 5 or more at a time ,? i got my eyes on an oring chain for Xt yamaha 250 t oring chain for $34.00 ,lately finding 128 link chain has been hard i am thinking about 130 an takeing few links out in the mxz no oring chain most of the middle end chains are like 5000 or more even the unibear for cheap is 4700 ,going with 16th an 45 rear ,but yes 128 links seem to be the most popular legnth ,thank you Dan

[Megadan]

the only one i did not get was the 27.5 at 1010 feet ,an you has said you were going to try a 32.5 an or 35,in the thread ,did you change your mind,at this point i would think the 30 would work pretty good going to go with aftermarket exhaust from crf230 ,an i am going with a real mikuni carb the only thing is the wings jets kit ,worst case i buy 27.5 but i got a better deal on shipping to buy 5 or more at a time ,? i got my eyes on an oring chain for Xt yamaha 250 t oring chain for $34.00 ,lately finding 128 link chain has been hard i am thinking about 130 an takeing few links out in the mxz no oring chain most of the middle end chains are like 5000 or more even the unibear for cheap is 4700 ,going with 16th an 45 rear ,but yes 128 links seem to be the most popular legnth ,thank you Dan

It would do you well to pay attention to the dates of the posts you are reading. :tup:

I was still experimenting with jetting. I found the 30 was actually too rich and causing said hesitation. I live at 1100ft and ended up with a 27.5 pilot and 115 -117.5 main depending on the air temp, with a 120 main when the temps got to the 40 degree range.

[pistolclass]

35 is pretty fat for a vm26 229cc bike. If the bike is totally stock I would start with a 110 main or 112.5 max and a 22.5 or 25 max pilot.

If you open it up with air box + exhaust then go 115 or 120 main and 25-30 pilot.

I don't know for sure but I would think you would need to really do some head work in order to need a 35 pilot.

My hawk runs and starts great, stock exhaust and air box with a 110 / 20 combo. I realize the 20 is a little lean but I made up for it with setting the needle at its richest setting and I'm 2 turns out. I will eventually install my 22.5 that is on my bench but it is running so good I really don't want to mess it up.

These are all starting points, not sure fire solutions. Good luck on you quest to tune your carb.

FYI I'm at 200 ft above sea level and It is 80+ degress.

[Ariel Red Hunter]

Personally, I would get the following sizes for a Hawk with a VM26.

Pilot. 25, 27.5, 30
Main:105, 107.5, 110, 112.5, 115, 117.5, 120

This range of jet sizes would cover and fine tune everything from completely stock on a hot day to cold temperatures on a bike with full bolt ons.Great point....ARH

[Hawk 229cc]

thank you plan is to try the 30 an 110 at 1010 feet where i live that can go up an down when i go into the valley ,moded air box but will put more holes in it ,going with cfr 230f
aftermarket exhaust ,we may , i see some guys just doing a good size air filter then useing the air box to store small things or delete it ? ,but plan is to get it as much air to it an thus as much power back from it ,the lack of power is ok ,but need a bit more i am sure the mods they suggest will be noticed in a few weeks ,week after 4th ,will have most of the suggested mods done,fun bike though ,starts right up an runs ok with the stock carb but just starved for air ,oh an neutral has been very easy to find ,feelling like i am 3rd gear when it is in 5th ,i am sure you know,time to wake it up

only pilot i dont have yet is the 27.5 ,probley the one i will need Naaaaaaaaaaaaaa will see,i will have my carb buddie look at this thread as i get a good shcooling in doing it myself ,big hands small parts:D

Edit to add that from 400 feet to 1000 ,around an 80 mile radious

[Gh426]

found this... www.historicmotorcycle.org.au/Adler/carby/jets.txt

Being a CHEAP SKATE / SCOT (Wny can confirm this ;) I will put my $4. .3mm-1.6mm HSS ebay kit to test. If i goof up, i will try the plumbers map gas torch lead soldering of said jet to go smaller. Others seem to get away with this

If anyone has tips, trycks or additional info ?? please speak up

FYI this acticle seems to be Ninja 250 centric so YMMV

CARBY JET SIZES
---------------

Everybody uses different methodology to establish their number for their given type of jet.

Mikuni for example, use a few different type of main jets in the various carbs commonly found on motorcycle engines.
Each of their different jets are tested and calibrated in different ways.

So for example, the Mikuni Long Hex, Short Hex, and Round-SlottedHead Jets in #71 size are 3 different Calibrations.
Besides the Physical differences, the Flow Rates are different.


Anyway, by whatever method that's used,
Jet Numbers are representative of a VOLUME of fuel.

CC's or Grams, usually per minute

So #71 Mikuni jet would flow about 71cc's of Gasoline per minute.
.................................................. ..
"Car" carb jets and the old Fuel Injection "Pills" are usually calibrated in numerical sizes according to Orifice Diameter.

Even then, the Jets are Labelled according to a Code, of sorts.

Holley Carbs for example, I can't recall Exactly how they determine the Number stamped on the jet,
but they Drill a bunch of jets during a production run.

Imagine the Hole Size being .071".
Then they will Flow Test all the jets in that batch.
Some will be LABELLED #70,,,some #71,,,some #72.

Meaning,,,they Drill & Finish the jets as precisely as practical,,,,and they are a NOMINAL #71 Batch.
Then Beyond That,,,they are Tested and labelled according to actual Flow Rates.
....................................
DynoJet Brand of Re-Jet Kits is very popular among motorcycles tuners.
They use Hole Size in Millimeters to label their jets
So a Dyno Jet Brand of jet for a Mikuni or Keihin Bike Carb ,,labelled as a #71 Jet,,,,
is actually 0.71 MM orifice diameter

I guess Bottom Line,,,among all the variety of jets,,,there's No Rhyme or Reason,,,or Standard.

They ALL are ultimately based on Fuel Flow Rate.
Because THAT is what is most convenient and accurate to MEASURE.

It is always most practical to number each graduation of Flow Rate sequentially.

But each Mfgr has their Own Scheme for translating Tested Flow Rate into a "Jet Number".

"A Rose by any other name....",,,
However they do it,,whatever they Call it,,,,it's all a Measurement & Ranking of Fuel Flow rate.

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JET MM INCHES NUMBERED JET SIZE
SIZE DRILL BIT WHEN DRILLED
#66 0.66mm 0.02598" #71
#68 0.68mm 0.02677"
#70 0.70mm 0.02756" #70 @ .0280" 71.12jet
#72 0.72mm 0.02835" #69 @ .0292" 74.2 jet
#79 0.79mm 0.0312" 1/32"@ .0312" 79.2 jet
#80 0.80mm 0.03150" #68 @ .0310" 78.7 jet
#83 0.83mm 0.03268" #66 @ .033" 83.8 jet
#89 0.89mm 0.035" #65 @ .035" 89 jet
#91.5 0.915mm 0.036" #64 @ .036" 91.5 jet
#96.5 0.965mm 0.038" #62 @ .038" 96.5 jet
#101.5 1.015mm 0.040" #60 101.5 jet
#105 1.05mm 0.0415" #59 @ 1.06mm 106 jet
#110 1.10mm 0.043" #57 @ 1.11mm 111 jet
#115 1.15mm 0.0455"
#120 1.20mm 0.047" #56 @ 1.19mm 119 jet
#125 1.25mm 0.049"
#130 1.30mm 0.051" #55 @ 1.33mm 133 jet
#135 1.35mm 0.053"
#140 1.40mm 0.055" #54 @ 1.40mm 140 jet

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The main Jap carbs are Mikuni and Keihin, Mikuni 6mm hex Jets are numbered by flow,
Keihin are by jet size 134.5 is 1.345mm.

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Dynojet - Mikuni - Keihin jet sizes conversion
From Ninja250Wiki

When you're jetting your carbs you will notice that the same size jets from different suppliers have different numbers.
The following chart will give you an idea of which numbers are the same for the different companies. Remember, though,
that this will only put you in the ballpark. Plenty of trial and error will be needed to get it right.

A note from Dynojet:
We are often asked for a "cross reference" sheet that compares our main jets to Mikuni or Keihin.
The fact is you cannot directly interchange the jets for a given size. Many things affect fuel flow through
a jet of the same orifice size. The entry and exit tapers of our main jets differ from those of other companies.
Due to this, the fuel flow changes as a function of velocity through the carburetor venturie.
This means that two jets of equal orifice size will have a different fuel flow curve relative to intake air speed.
At a certain speed the two may flow equally, but a change in velocity changes the flow characteristics.
The Dynojet main jet hole size is measured in millimeters. For example, a DJ142 has a 1.42mm hole.
Michael Cory
Dynojet Research & Development

Available jets
You never know what kind of jets you might find at your local shop when you try to find new jets.
Wes says to just ask for jets that will fit in a Harley. That keeps the sales droid from having to think too much.
Asking about Ninja 250s causes all sorts of confusion. Having this chart, and knowing what will fit and how they
compare to each other, will help you figure out if they have what you can use.

There are four current sources of main jets which will fit the Ninja 250:

1) Keihin - OEM main jets - Jets are measured using an unknown convention in steps of 2 or 3.
Available from Kawasaki dealers 2 sizes larger and 2 smaller than the Ninja 250's stock #105 main jets.

2) Dynojet - Measured in mm. Dynojet numbers are simply the hole diameter. A 140DJ main has a 1.40mm (0.055")
diameter hole in it at the threaded end. Available in .02mm increments. Marked with a 'DJ' on the jet.

3) Precision Engineering - Also sold under the names 'RD Precision Engineering' and 'Freeman Automotive'
All are marked with an 'AB' on the jet. Like Dynojet, measured in mm, but come in .025mm increments.

4) Mikuni - Made for Mikuni Carburetors, but will also fit Keihin. Available in 2.5 increments.
Mikuni uses yet another measurement convention - reportedly based on flow rate.
The result is that Mikuni's sizes are vastly different from the other makers'.

The different manufacturers' jets will have a slightly different taper to the orifice, which can affect flow.
This means that there will most likely be very slight differences between the same diameter jets from different makers.

The measurements in this chart are from the actual measured orifice size, in millimeters. Keihin 105 is the stock main jet.


unknown = Not yet measured
n/a = This size not available from this manufacturer

Measured mm Keihin Dynojet Precision Mikuni Flow(cc/sec)
(AB)
.94 unknown DJ094 n/a 87.5 2.19
.95 n/a n/a AB95 n/a 2.24
.96 unknown DJ096 n/a 90 2.29
.975 n/a n/a AB97.5 n/a 2.36
.98 100 DJ098 n/a n/a 2.38
1.00 102 DJ100 AB100 92.5 2.48
1.02 105 DJ102 n/a 95 2.58
1.025 n/a n/a AB102.5 n/a 2.61
1.04 108 DJ104 n/a 97.5 2.69
1.05 n/a n/a AB105 n/a 2.74
1.06 110 DJ106 n/a 100 2.79
1.075 n/a n/a AB107.5 n/a 2.87
1.08 unknown DJ108 n/a n/a 2.90
1.10 unknown DJ110 AB110 102.5 3.02
1.12 unknown DJ112 n/a 105 3.13
1.125 n/a n/a AB112.5 n/a 3.16
1.14 unknown DJ114 n/a 107.5 3.25


Again, the chart is fine to use to get you in the ballpark. However, once you start zeroing in on the correct
jetting specs, you should be basing your jetting changes based on what the bike is telling you--not what someone
else (who isn't testing with you) says is right for your bike/situation.
There aren't really any shortcuts to getting jetting right.

Read the rest of the information in the jetting section at
http://faq.ninja250.org/wiki/I_want_to_improve_my_carburetor_jetting

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Dellortos are rated by size, so a 120 main is actually 1.2mm

http://www.bikechatforums.com/viewtopic.php?t=17124

Mikunins are measured by flow rate so a 120 main flows 120cc/min

http://rd500lc.free.fr/technics/jet_size_en.htm

Good Dellorto tuning book:

http://www.morinispecial.it/manuali/dellorto_motorcycle_carburetor_tuning_guide.pdf

If you could find a way to flow test all the dellorto jets and all the mikuni jets you have then
it would be pretty easy to put together a comparision chart between the two. Keep in mind that
not all jets of the same # will flow the same amount due to machining diffrences (see first link).

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Mikuni, Dynajet, and Kehin all have different drill sizes for the same jet number:



drill Dell'Orto # drill Adler
inches --- Kehein # -- DynoJets # -- Mikuni # -- mm --- Bing #

0.035 ----- 92.5 ------- 92 ---------- 86.3 ----- 0.92
0.036 ----- 95 --------- 94 ---------- 88.1 ----- 0.94
0.037 ----- 97.5-------- 96 ---------- 90.0 ----- 0.96
0.038 ---- 100 --------- 98 ---------- 91.9 ----- 0.98
0.039 ---- 102.5------- 100 ---------- 93.8 ----- 1.00 ---- 110
0.040 ---- 105 -------- 102 ---------- 95.6 ----- 1.02
0.041 ---- 107.5------- 104 ---------- 97.5 ----- 1.04 ---- 115
0.042 ---- 110 -------- 106 ---------- 99.4 ----- 1.06
0.043 ---- 112.5------- 108 --------- 101.3 ----- 1.08
0.044 ---- 115 -------- 110 --------- 103.1 ----- 1.10
0.045 ---- 117.5------- 112 --------- 105.0 ----- 1.12 ---- 120
0.046 ---- 120 -------- 114 --------- 106.9 ----- 1.14
0.047 ---- 122.5------- 116 --------- 108.8 ----- 1.16
0.048 ---- 125 -------- 118 --------- 110.6 ----- 1.18
0.049 ---- 127.5------- 120 --------- 112.5 ----- 1.20
0.050 ---- 130 -------- 122 --------- 114.4 ----- 1.22
0.051 ---- 132.5------- 124 --------- 116.3 ----- 1.24
0.052 ---- 135 -------- 126 --------- 118.1 ----- 1.26
0.053 ---- 137.5------- 128 --------- 120.0 ----- 1.28
0.054 ---- 140 -------- 130 --------- 121.9 ----- 1.30
0.055 ---- 142.5------- 132 --------- 123.8 ----- 1.32
0.056 ---- 145 -------- 134 --------- 125.6 ----- 1.34
0.057 ---- 147.5------- 136 --------- 127.5 ----- 1.36
0.058 ---- 150 -------- 138 --------- 129.4 ----- 1.38
0.059 ---- 152.5------- 140 --------- 131.3 ----- 1.40
0.060 ---- 155 -------- 142 --------- 133.1 ----- 1.42
0.061 ---- 157.5------- 144 --------- 135.0 ----- 1.44
0.062 ---- 160 -------- 146 --------- 136.9 ----- 1.46
0.063 ---- 162.5------- 148 --------- 138.8 ----- 1.48
0.064 ---- 165 -------- 150 --------- 140.6 ----- 1.50
0.065 ---- 167.5------- 152 --------- 142.5 ----- 1.52
0.066 ---- 170 -------- 154 --------- 144.4 ----- 1.54
0.067 ---- 172.5------- 156 --------- 146.3 ----- 1.56
0.068 ---- 175 -------- 158 --------- 148.1 ----- 1.58
0.069 ---- 177.5------- 160 --------- 150.0 ----- 1.60
0.070 ---- 180 -------- 162 --------- 151.9 ----- 1.62
0.071 ---- 182.5------- 164 --------- 153.8 ----- 1.64
0.072 ---- 185 -------- 166 --------- 155.6 ----- 1.66
0.073 ---- 187.5------- 168 --------- 157.5 ----- 1.68
0.074 ---- 190 -------- 170 --------- 159.4 ----- 1.70
0.075 ---- 192.5------- 172 --------- 161.3 ----- 1.72
0.076 ---- 195 -------- 174 --------- 163.1 ----- 1.74
0.077 ---- 197.5------- 176 --------- 165.0 ----- 1.76
0.078 ---- 200 -------- 178 --------- 166.9 ----- 1.78
0.079 ---- 202.5------- 180 --------- 168.8 ----- 1.80
0.080 ---- 205 -------- 182 --------- 170.6 ----- 1.82
0.081 ---- 207.5------- 184 --------- 172.5 ----- 1.84
0.082 ---- 210 -------- 186 --------- 174.4 ----- 1.86
0.083 ---- 212.5------- 188 --------- 176.3 ----- 1.88
0.084 ---- 215 -------- 190 --------- 178.1 ----- 1.90
0.085 ---- 217.5------- 192 --------- 180.0 ----- 1.92
0.086 ---- 220 -------- 194 --------- 181.9 ----- 1.94
0.087 ---- 222.5------- 196 --------- 183.7 ----- 1.96
0.088 ---- 225 -------- 198 --------- 185.6 ----- 1.98
0.089 ---- 227.5------- 200 --------- 187.5 ----- 2.00

[Cravin01]

The elusive pilot jet of the PZ30 can be found on ebay and Aliexpress.

https://www.aliexpress.com/item/Motorcycles-modified-with-a-cold-start-short-Keihin-carburetor-pilot-jet-nozzle-vice-injectors-Nozzle-12/32822840523.html

The knock off pumper PZ30 does have needle hight adjustment which the PZ30 that came on the bike does not, I'm too far in with the Kehein's to turn back but so far I've had good experiences with them.