rejetting - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
From the gas tank to the carbs
All fuel system discussion

 1Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 12 (permalink) Old 01-24-2016, 05:47 PM Thread Starter
Member
 
Join Date: Jan 2016
Location: baltimore md
Posts: 32
iTrader: (0)
 
rejetting

i am going to earshave and use pod filters also open exhuast up.so as far as rejetting do i need to get a entire jet kit where i will be drilling the slides and everything or can i just get the 142/42 jets and install them any suggestions and help will be greatly appreciated ty
boanz is offline  
Sponsored Links
Advertisement
 
post #2 of 12 (permalink) Old 01-24-2016, 06:20 PM
Alpha Geek
 
Hexadecimus's Avatar
 
Join Date: Oct 2013
Location: Midwest USA
Posts: 487
iTrader: (1)
 
40, 140 with a coaster/marbling and 3.5 turns is probably closer. 42 pilots might be okay, but it will suck a lot more gas and you'll need to dial back the screws to find best lean idle. "Best lean idle" first (http://www.redlineweber.com/html/Tec...lean_best_.htm), then mains at WOT and a plug chop to set your top end, then shims if necessary to cure lean surging at cruise speeds and tune the midrange. If 4 shims doesn't do it, go to 42's and zero shims, retune from the beginning. Midrange is still mostly pilots, so a bump up there can help.

I run 38/140 and 3.5-4 turns with pod filters, coastered, and wide open slip-on Screamin' Eagle "mufflers". I put that in quotes because they're empty pipes.
I have no lean problems, starts and runs great, and probably the best mpg of anyone on here.

Excerpt from my patented super duper nifty neato jet cross-section charts:

# area % change
38 0.11 1.00
40 0.13 1.11
42 0.14 1.22

# area % change
132 1.37 1.00
135 1.43 1.05
138 1.50 1.09
140 1.54 1.12
142 1.58 1.16
145 1.65 1.21
148 1.72 1.26
150 1.77 1.29

If anyone is going past about +15%, they either have forged internals and a turbo, they're masking some other huge problem, or they're copying bad advice from all the people who like to massively over-jet.

As you can see, there's a huge % change when you swap pilots. That's why we need to play with the screws to fine tune it. Each size bump begins to drop in larger sizes because it's based on diameter, while fuel flow is based on cross-sectional area. We really need about a +15% option on pilots and #138 mains.

Think about how much extra air you're getting and power you're making. Most intake/exhaust combinations won't get more than 5-10% gain, 8-12% if you're doing lollipops, torque cones, etc. to really tune it right. That's the increase in jet size you should shoot for.


Last edited by Hexadecimus; 01-24-2016 at 06:24 PM.
Hexadecimus is offline  
post #3 of 12 (permalink) Old 01-24-2016, 06:33 PM
FREEBIRDS MC CENTRAL NY
 
OleDirtyDoc's Avatar
 
Join Date: May 2011
Location: Norwich,NY
Posts: 16,027
iTrader: (0)
     
Garage
Send a message via Yahoo to OleDirtyDoc
I'm at 1100ft, degoated with screaming eagles, earshave with k&n pods,and 140/40 and two shims.but every bike is different and Hex's guidelines are a great start.now Jason,gonna put up some pics of that new toy ya got?

ONE RATS ASS GIVEN PER POST
Support your local FREEBIRDS MC
1986/5 Vn700/750 Frankenfook cross eyed bitch "Mellisa Fayhe"
I am a BIKER and i'm proud.FREEBIRDS MC CENTRAL NY

lowered with progessive 412 10" shocks
rejetted for K/N Pods part#rc 2340
sportster seat

'I didn't lose my mind.i gave it away

BRING BACK WOLFIE."Peace and Carrots"RIP
"And I'm free...as a bird"John Lennon Free as a Bird
"I only carry when I have my pants on"Joe Robinson RIP aka Old Dog
OleDirtyDoc is offline  
 
post #4 of 12 (permalink) Old 01-24-2016, 07:08 PM Thread Starter
Member
 
Join Date: Jan 2016
Location: baltimore md
Posts: 32
iTrader: (0)
 
tyvm on the info was just going off another on here i saw with those jets.so what jet kit should i go with??i know of factory pro,dynajet and i was looking at the 6sigma kit.what do u suggest?as im new to the motorcycle repair and the performance side of it all.i am a auto mechanic with quite a few years exp.pretty much if it has a motor i can figure it out.ty again
boanz is offline  
post #5 of 12 (permalink) Old 01-24-2016, 07:13 PM Thread Starter
Member
 
Join Date: Jan 2016
Location: baltimore md
Posts: 32
iTrader: (0)
 
oh and what size pods am i looking for i saw u had something on ur bike rc 23xx???
boanz is offline  
post #6 of 12 (permalink) Old 01-24-2016, 07:44 PM
FREEBIRDS MC CENTRAL NY
 
OleDirtyDoc's Avatar
 
Join Date: May 2011
Location: Norwich,NY
Posts: 16,027
iTrader: (0)
     
Garage
Send a message via Yahoo to OleDirtyDoc
K&N 2340

ONE RATS ASS GIVEN PER POST
Support your local FREEBIRDS MC
1986/5 Vn700/750 Frankenfook cross eyed bitch "Mellisa Fayhe"
I am a BIKER and i'm proud.FREEBIRDS MC CENTRAL NY

lowered with progessive 412 10" shocks
rejetted for K/N Pods part#rc 2340
sportster seat

'I didn't lose my mind.i gave it away

BRING BACK WOLFIE."Peace and Carrots"RIP
"And I'm free...as a bird"John Lennon Free as a Bird
"I only carry when I have my pants on"Joe Robinson RIP aka Old Dog
OleDirtyDoc is offline  
post #7 of 12 (permalink) Old 07-13-2016, 02:29 PM
Junior Member
 
Join Date: Jul 2016
Posts: 4
iTrader: (0)
 
Quote:
Originally Posted by Hexadecimus View Post

I run 38/140 and 3.5-4 turns with pod filters, coastered, and wide open slip-on Screamin' Eagle "mufflers". I put that in quotes because they're empty pipes.
Where do you get your coasters?
Tank126 is offline  
post #8 of 12 (permalink) Old 07-13-2016, 08:03 PM
Senior Member
 
Join Date: Mar 2016
Location: MI
Posts: 292
iTrader: (0)
 
Quote:
Originally Posted by Tank126 View Post
Where do you get your coasters?
Coaster

or do what I and other cheap people did and just use 5/8" caps that are .50ea at auto parts store.
OleDirtyDoc likes this.

2002 vn750
AGM battery, Shinko 230 tires oversized front
Ear shaved - k&n pods, drilled clutch basket
MCCT
40/138 jetting

If I can split a case and make it work - you can too!
Forum pictures:http://s150.photobucket.com/user/Gid...?sort=3&page=1
gidaeon is offline  
post #9 of 12 (permalink) Old 07-14-2016, 09:35 AM
FREEBIRDS MC CENTRAL NY
 
OleDirtyDoc's Avatar
 
Join Date: May 2011
Location: Norwich,NY
Posts: 16,027
iTrader: (0)
     
Garage
Send a message via Yahoo to OleDirtyDoc
Quote:
Originally Posted by gidaeon View Post
Coaster

or do what I and other cheap people did and just use 5/8" caps that are .50ea at auto parts store.
Yup 5/8" caps

ONE RATS ASS GIVEN PER POST
Support your local FREEBIRDS MC
1986/5 Vn700/750 Frankenfook cross eyed bitch "Mellisa Fayhe"
I am a BIKER and i'm proud.FREEBIRDS MC CENTRAL NY

lowered with progessive 412 10" shocks
rejetted for K/N Pods part#rc 2340
sportster seat

'I didn't lose my mind.i gave it away

BRING BACK WOLFIE."Peace and Carrots"RIP
"And I'm free...as a bird"John Lennon Free as a Bird
"I only carry when I have my pants on"Joe Robinson RIP aka Old Dog
OleDirtyDoc is offline  
post #10 of 12 (permalink) Old 07-14-2016, 10:08 AM
Alpha Geek
 
Hexadecimus's Avatar
 
Join Date: Oct 2013
Location: Midwest USA
Posts: 487
iTrader: (1)
 
I tried caps but my bike blew them off within 2 miles so I corked from the inside as well, plus caps, plus RTV between them. I prefer coasters. You can also "marble" the hoses.

Hexadecimus is offline  
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

Once registered, your User Name"cannot be changed". We can make exceptions within 7 days, but after that, it is set in stone.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome