Am I running too lean? Too rich? - 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 75 (permalink) Old 07-22-2009, 08:44 PM Thread Starter
Senior Member
 
Join Date: Jun 2009
Location: Chicago, Illinois
Posts: 156
iTrader: (0)
 
Send a message via AIM to Acid7711
Am I running too lean? Too rich?

I just finished completing my ear shave on my bike. It went very well and I'm very please with the results thus far, but I'm having a little problem. I cleaned both carbs out completely, synced the carbs, and turned both air/fuel idle screws out 3 turns. I've also tried turning these back in to 2.5, but it makes no difference.


Under the guidance of Lance (Thanks again for everything!!!) I installed 42 pilot jets and 145 main jets with 2 needle shims under each needle.

Bike starts up and idles great! Under full throttle the bike feels like it moves great. The problem comes in when I'm cruising at around 50-60mph. It feels (and sounds) like it's mising, cutting out, hesitating. At first, I thought air was getting to the vent hose, so I moved this way further back BEHIND the battery, no change here. That wasn't the problem.

On the way to work tonight, I thought maybe I'd give it some choke and see if this changed anything. Under full choke, cruising, it seems to stop the surging problem I'm experiencing. Would this mean I'm running too lean and need larger jets? I pulled the plugs, all 4 look about the same, and are light tan, they almost do look too lean, but I just don't know enough about carbs to fix this on my own.



I believe, (hopefully I'm right ) that I'm running too lean. I don't, however, know which of the two jets, the pilot or the main, that I need to enlarge?

Any suggestions? Thanks for any help that can be offered




*** I should mention, I have De-goated the exhaust and drilled 8 holes in the baffles. ***
Acid7711 is offline  
Sponsored Links
Advertisement
 
post #2 of 75 (permalink) Old 07-22-2009, 09:00 PM
Members who have donated towards server costs
 
93VN750's Avatar
 
Join Date: May 2006
Location: Tampa, Florida
Posts: 1,766
iTrader: (2)
 
Send a message via Skype™ to 93VN750
Quote:
Originally Posted by Acid7711 View Post
I just finished completing my ear shave on my bike. It went very well and I'm very please with the results thus far, but I'm having a little problem. I cleaned both carbs out completely, synced the carbs, and turned both air/fuel idle screws out 3 turns. I've also tried turning these back in to 2.5, but it makes no difference.


Under the guidance of Lance (Thanks again for everything!!!) I installed 42 pilot jets and 145 main jets with 2 needle shims under each needle.

Bike starts up and idles great! Under full throttle the bike feels like it moves great. The problem comes in when I'm cruising at around 50-60mph. It feels (and sounds) like it's mising, cutting out, hesitating. At first, I thought air was getting to the vent hose, so I moved this way further back BEHIND the battery, no change here. That wasn't the problem.

On the way to work tonight, I thought maybe I'd give it some choke and see if this changed anything. Under full choke, cruising, it seems to stop the surging problem I'm experiencing. Would this mean I'm running too lean and need larger jets? I pulled the plugs, all 4 look about the same, and are light tan, they almost do look too lean, but I just don't know enough about carbs to fix this on my own.



I believe, (hopefully I'm right ) that I'm running too lean. I don't, however, know which of the two jets, the pilot or the main, that I need to enlarge?

Any suggestions? Thanks for any help that can be offered




*** I should mention, I have De-goated the exhaust and drilled 8 holes in the baffles. ***
Did you try leaving the choke where it cruised well and run it WOT? at idle?

Jon

93VN750, under re-construction
vn750.com Member # 828

Rick's Stator and R/R
MF AGM Battery
Coastered
Degoated
Shaved & Jetted
Iridium's
MAC Tapered Staggered Pipes
Battery/Temp/Clock Gauge
Stainless Steel Brake Lines
Dunlop D-404's
23,XXX miles and holding pending gasket change (underway!!!)
93VN750 is offline  
post #3 of 75 (permalink) Old 07-22-2009, 09:03 PM
The Professor
 
lance328's Avatar
 
Join Date: Feb 2008
Location: BUFORD, GEORGIA
Posts: 3,147
iTrader: (15)
   
Quote:
Originally Posted by Acid7711 View Post
I just finished completing my ear shave on my bike. It went very well and I'm very please with the results thus far, but I'm having a little problem. I cleaned both carbs out completely, synced the carbs, and turned both air/fuel idle screws out 3 turns. I've also tried turning these back in to 2.5, but it makes no difference.


Under the guidance of Lance (Thanks again for everything!!!) I installed 42 pilot jets and 145 main jets with 2 needle shims under each needle.

Bike starts up and idles great! Under full throttle the bike feels like it moves great. The problem comes in when I'm cruising at around 50-60mph. It feels (and sounds) like it's mising, cutting out, hesitating. At first, I thought air was getting to the vent hose, so I moved this way further back BEHIND the battery, no change here. That wasn't the problem.

On the way to work tonight, I thought maybe I'd give it some choke and see if this changed anything. Under full choke, cruising, it seems to stop the surging problem I'm experiencing. Would this mean I'm running too lean and need larger jets? I pulled the plugs, all 4 look about the same, and are light tan, they almost do look too lean, but I just don't know enough about carbs to fix this on my own.



I believe, (hopefully I'm right ) that I'm running too lean. I don't, however, know which of the two jets, the pilot or the main, that I need to enlarge?

Any suggestions? Thanks for any help that can be offered




*** I should mention, I have De-goated the exhaust and drilled 8 holes in the baffles. ***
Turn your screws out to 3.5 turns, if that does not fix it then go to a larger main jet. #148 or #150


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote
lance328 is offline  
 
post #4 of 75 (permalink) Old 07-22-2009, 09:08 PM Thread Starter
Senior Member
 
Join Date: Jun 2009
Location: Chicago, Illinois
Posts: 156
iTrader: (0)
 
Send a message via AIM to Acid7711
I did not try leaving the choke on any time except while cruising, ever since the new battery, I've never had to even use the choke. It was just a shot in the dark.

I will try turning these screws out to 3.5 turns tonight, and will know if anything has changed tomorrow morning. Originally, I had these turned out to 3.5 after some thinking, but the first time I tried to start it up, it was idling a little rough, so I put them back to 3.
Acid7711 is offline  
post #5 of 75 (permalink) Old 07-22-2009, 09:16 PM
The Professor
 
lance328's Avatar
 
Join Date: Feb 2008
Location: BUFORD, GEORGIA
Posts: 3,147
iTrader: (15)
   
Quote:
Originally Posted by Acid7711 View Post
I did not try leaving the choke on any time except while cruising, ever since the new battery, I've never had to even use the choke. It was just a shot in the dark.

I will try turning these screws out to 3.5 turns tonight, and will know if anything has changed tomorrow morning. Originally, I had these turned out to 3.5 after some thinking, but the first time I tried to start it up, it was idling a little rough, so I put them back to 3.
I realy don,t think it will correct your problem but try it. also try turning the screws to 1.5 turns. If no change get the larger main jets, I would try the #150 first then go from there.


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote
lance328 is offline  
post #6 of 75 (permalink) Old 07-22-2009, 10:00 PM Thread Starter
Senior Member
 
Join Date: Jun 2009
Location: Chicago, Illinois
Posts: 156
iTrader: (0)
 
Send a message via AIM to Acid7711
Ok I'll be rough, but I'll probably stay at work an extra hour tomorrow and wait till the store opens to see if they have the jets in stock hehe.
Acid7711 is offline  
post #7 of 75 (permalink) Old 07-23-2009, 02:07 AM Thread Starter
Senior Member
 
Join Date: Jun 2009
Location: Chicago, Illinois
Posts: 156
iTrader: (0)
 
Send a message via AIM to Acid7711
When exactly are these pilot and main jets used? I would think the pilot would be used at the cruising throttle since it's not open very much, unless pilot does most of the work and anything like 50%+ goes main? I'm confused and I don't know much about carbs.
Acid7711 is offline  
post #8 of 75 (permalink) Old 07-23-2009, 03:52 AM
The Professor
 
lance328's Avatar
 
Join Date: Feb 2008
Location: BUFORD, GEORGIA
Posts: 3,147
iTrader: (15)
   
Quote:
Originally Posted by Acid7711 View Post
When exactly are these pilot and main jets used? I would think the pilot would be used at the cruising throttle since it's not open very much, unless pilot does most of the work and anything like 50%+ goes main? I'm confused and I don't know much about carbs.
The pilot gives fuel for idle and throttle response until enough vacuum can open the piston for the main. The ammount of incomming air will regulate the main jet. The pilot gets it going the main keeps it going.


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote
lance328 is offline  
post #9 of 75 (permalink) Old 07-23-2009, 04:08 AM Thread Starter
Senior Member
 
Join Date: Jun 2009
Location: Chicago, Illinois
Posts: 156
iTrader: (0)
 
Send a message via AIM to Acid7711
Gotchya, so you think 42's for the pilots are ok, just the mains are too small maybe?
Acid7711 is offline  
post #10 of 75 (permalink) Old 07-23-2009, 04:23 AM
The Professor
 
lance328's Avatar
 
Join Date: Feb 2008
Location: BUFORD, GEORGIA
Posts: 3,147
iTrader: (15)
   
Quote:
Originally Posted by Acid7711 View Post
Gotchya, so you think 42's for the pilots are ok, just the mains are too small maybe?
With the info you have given , YES!! If the pilot is giving too much fuel you can close the screws. The mains can only be adjusted by changing them. Since your problem was solved by opening the choke circuit which dumps in more fuel. logic dictates you need more fuel from the main jet circuit.


85 VN700 "Old Yella"

REBUILT ENGINE
CUSTOM PAINT
VANCE & HINES CRUZERS
EAR SHAVED AND RE-JETTED W/K&N'S
DUNLOP ELITE K591 FRONT & REAR
VOLTMETER
SYNTHETIC BRAKE FLUID
SYNTHETIC OIL & GEAR LUBE
PLEXISTAR 2 WINDSHIELD
SPLINES LUBED
ACCT'S GREASED W/TOC SPRINGS
COASTERD
LEATHER SADDLE BAGS
LEATHER TOOL AND ROLL BAG
PICKUP COILS GAPPED AT .018"
NGK CAP, WIRES, IRIDUMS
BARNETT FRICTION PLATES & SPRINGS
CUSTOM GRIPS, MIRRORS, LEVERS
ORIGINAL STATOR & R/R 14.5v
DEKA MF AGM ETX15L

Best Auto/Moto Insurance | Motorcycle Protection Today | FREE Trade-In Quote
lance328 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