Best Dellorto jetting database

[jaguar57]

Contribute to this jetting database and get a free evaluation of your jetting in a graph such as you see here. The red graph shows the jetting richness from closed throttle to WOT. Above the horizontal 1.0 line is too rich, and below it is too lean. Every data point needs to be fulfilled. You can make this the best database ever for Dellorto because it is the most complete. Just post your details here and if you want the graph emailed to you in case it looks terrible then just email me at [e-mail]

bike:

carb model:

carb size:

idle jet #:

air screw turns out:

needle #:

main jet #:

tried different main jets? (Y/N):
(This tells whether or not the main jet you are using is the most optimal one)

slide cutaway #:

% ethanol in fuel:

elevation:

reed valve? (Y/N):

type exhaust pipe? (1/2/3):

1. just header and muffler, no expansion chamber.

2. expansion chamber with straight header

3. expansion chamber with expanding header

[Lucass2T]

Dont go there. It'll get you into more problems than figuring out jet sizes yourself.

No bike is the same, even when 1 person would assemble two identical motors at the same time.

Just start waaayy to big and work your way down. Its easy, just follow this one simple step.

[oldgeek]

I agree with ^^ 100% but I wanna see what my graph looks like

bike: Kymco ZX 103cc 2T

carb model: PHBG clone

carb size: 21mm

idle jet #: 40

air screw turns out: 1.5

needle #: 12 on 3rd leanest notch

Needle Jet# 264 < very important spec.

main jet #: 100

tried different main jets? (Y/N): yes, of course

slide cutaway #: 30

% ethanol in fuel: 10%

elevation: sealevel

reed valve? (Y/N): Y

type exhaust pipe? (1/2/3): Custom # 3

3. expansion chamber with expanding header

[jaguar57]

Aerox, here's your graph. The mid throttle richness is something you probably can't even feel. If you ride mid throttle a lot then maybe the plug will show itself a tad darker than it should. This mid throttle richness is typical of single taper needles. Race bikes almost always have dual or triple tapered needles to have a near perfect jetting thru the whole range. But strangely enough all the needles for the PHBG are single taper. I'd tell you how to make your own dual tapered needle but you'd need to start with one with 1.2 degrees or less and 1.7 degrees is the smallest tapered needle (W24) there is for the PHBG. see all the needles listed on my site at www.dragonfly75.com/moto/jettingDellOrto.html
If you like DIY projects you might try a X51 needle and cut off the top and make new clip grooves so that it has the same distance from bottom clip groove to beginning of taper as the W12 needle. I would do it in a heartbeat but that's just my nature. I love getting my hands dirty and doing things no one else has done before. On the graph the light blue line is the "perfect" jetting graph. The dark blue graph is the actual jetting according to the data entered. The red graph shows the difference between the two so that anything over 1.00 is rich and anything under 1.00 is lean. But like I said, 7% rich is hardly enough to feel at mid range. Maybe at full throttle/ full power you could feel 7% off.

[oldgeek]

Nov 14, 2019 16:32:19 GMT -5 jaguar57 said:

Aerox, here's your graph. The mid throttle richness is something you probably can't even feel. If you ride mid throttle a lot then maybe the plug will show itself a tad darker than it should. This mid throttle richness is typical of single taper needles. Race bikes almost always have dual or triple tapered needles to have a near perfect jetting thru the whole range. But strangely enough all the needles for the PHBG are single taper. I'd tell you how to make your own dual tapered needle but you'd need to start with one with 1.2 degrees or less and 1.7 degrees is the smallest tapered needle (W24) there is for the PHBG. see all the needles listed on my site at www.dragonfly75.com/moto/jettingDellOrto.html
If you like DIY projects you might try a X51 needle and cut off the top and make new clip grooves so that it has the same distance from bottom clip groove to beginning of taper as the W12 needle. I would do it in a heartbeat but that's just my nature. I love getting my hands dirty and doing things no one else has done before. On the graph the light blue line is the "perfect" jetting graph. The dark blue graph is the actual jetting according to the data entered. The red graph shows the difference between the two so that anything over 1.00 is rich and anything under 1.00 is lean. But like I said, 7% rich is hardly enough to feel at mid range. Maybe at full throttle/ full power you could feel 7% off.

I must admit I chuckled at your calculator, but I WAS WRONG to do so. It basically agrees with my butt dyno findings! after seeing my setup profiled I looked further at your web page. It is clear that you have a tremendous understanding of carbs for the 2T, and you spent a lot of time developing your spreadsheet.

I see that you are selling several different calculators for the 2T are they all your own work?

[ryan_ott]

I’m curious... This is from my last setup.

bike: 2008 Yamaha Zuma
70cc LC Polini Corsa

carb model: Genuine PHBG 21mm

carb size: 21mm

idle jet #: 40

air screw turns out: 1 3/4

needle #: W9 2nd from top

needle jet # 264

main jet #: 86

tried different main jets? (Y/N): Y
(This tells whether or not the main jet you are using is the most optimal one)

slide cutaway #: 40

% ethanol in fuel: 10

elevation: 340

reed valve? (Y/N): Y

type exhaust pipe? (1/2/3): 3

Yasuni C16

[jaguar57]

Oldgeek, I'm glad to of pleasantly surprised you. Yes all the spreadsheets are mine. I started making them about 8 years ago.

Ryan, this is your graph and the second graph is with a W12 which has a smaller taper angle which is a step in the right direction but still it really needs a dual tapered needle.

[Kenho21]

Wow this is awesome. Wish I had a Dell carb... just got a CP.

[Zino]

Nov 14, 2019 8:39:22 GMT -5 jaguar57 said:

Contribute to this jetting database and get a free evaluation of your jetting in a graph such as you see here. The red graph shows the jetting richness from closed throttle to WOT. Above the horizontal 1.0 line is too rich, and below it is too lean. Every data point needs to be fulfilled. You can make this the best database ever for Dellorto because it is the most complete. Just post your details here and if you want the graph emailed to you in case it looks terrible then just email me at [e-mail]

bike: 2004 yamaha zuma

carb model: dellorto 

carb size:19mm

idle jet #: 40

air screw turns out: 1 1/4 turns out

needle #: W7

main jet #:90

tried different main jets? (Y/N): 88 ,92,95
(This tells whether or not the main jet you are using is the most optimal one)

slide cutaway #:40

% ethanol in fuel:0

elevation:800 feet

reed valve? (Y/N):y

type exhaust pipe? (1/2/3):2

1. just header and muffler, no expansion chamber.

2. expansion chamber with straight header

3. expansion chamber with expanding header

From my last dellorto setup