Jerking/popping at 55mph+, 4krpm - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
Carbs and Fuel System
From the gas tank to the carbs
All fuel system discussion

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 15 (permalink) Old 08-09-2008, 09:36 PM Thread Starter
 
Join Date: Jun 2008
Posts: 17
iTrader: (0)
 
Angry Jerking/popping at 55mph+, 4krpm

ok...so i've checked all exhaust connections using the smoke technique...tightened where i needed to. I've marbled and adjusted for the least amount of decellaration popping around 3k rpm. check all connections at the carbs with wd-40...no leaks. It's still running rich, you can smell the gas behind me when i ride. What else could this be? Spark plug wires?? could this be a battery problem???...I'm lost, please help!!! riding season is going to be over in 3 weeks...

thanks in advance
-nick
nicko915 is offline  
Sponsored Links
Advertisement
 
post #2 of 15 (permalink) Old 08-09-2008, 09:42 PM
 
Join Date: Apr 2008
Posts: 1
iTrader: (0)
 
mine was doing the same thing, I got a bottle of sea foam carb cleaner unhooked the gas line started the bike and let it suck half the bottle up the shut her down and let it set for a couple days. dumped the rest in the tank and it seemed to cure the problem.
post #3 of 15 (permalink) Old 08-09-2008, 10:15 PM
Members who have donated towards server costs
 
750Doug's Avatar
 
Join Date: Apr 2008
Location: S.E. Michigan
Posts: 2,850
iTrader: (10)
   
Sounds like a float issue. Have you been into the carbs at all?

I'd try the Seafoam as described above, and/or do a Seafoam search for a dozen other ways to use it to clean the carbs. The next step is removing the carbs and opening them for physical inspection/cleaning.

Some folks have had good results with Seafoam, other folks had to pull and open the carbs anyway. Give it a shot, it may work good for you.
750Doug is offline  
 
post #4 of 15 (permalink) Old 08-09-2008, 10:20 PM
Members who have donated towards server costs
 
Sky Rider's Avatar
 
Join Date: Jun 2006
Location: Corpus Christi, Texas
Posts: 1,647
iTrader: (0)
 
Try Seafoam first to see if it will work for you. If that fails, a carb pull and cleaning is in order.

Jim W
93 VN 750 "Ursula"
Moved R/R 08Sep06
R/R rewire 17Feb07
New R/R, Installed 14Jun08
New Stator installed 10 Jun08
Maintenance Free Battery 12Jan08
21480 Miles
VROC #8542
Sky Rider is offline  
post #5 of 15 (permalink) Old 08-10-2008, 02:31 PM Thread Starter
 
Join Date: Jun 2008
Posts: 17
iTrader: (0)
 
ok...i forgot to mention that i've had the carbs off 3 different times...replaced every o-ring in them, scrubbed them clean, adjusted the float bowl level and did the seafoam through the tank. The bike runs great until 55mph/3800rpm. It doesn't do the same thing when it's up on its center stand and i run it through the gears to 5th gear and put it at 3800. This is why i'm thinking it could be electrical.
nicko915 is offline  
post #6 of 15 (permalink) Old 08-10-2008, 04:13 PM
Members who have donated towards server costs
 
Sky Rider's Avatar
 
Join Date: Jun 2006
Location: Corpus Christi, Texas
Posts: 1,647
iTrader: (0)
 
We'll assume, just for arguements sake, that the carbs are clean. Since it performs fine on the center stand, that means the problem only manifests when under load. How old are the spark plugs? How old are the spark plug wires? Have you pulled the plugs and "read" them? If the plugs on one cylinder are fouled, it could contibute to your problem. Are the wires on tight? At night, do you get an electrical light show where the right front spark plug cap touches or is near the throttle cables?

If your wires or plugs are old, this may be the problem or one cause of it.

Jim W
93 VN 750 "Ursula"
Moved R/R 08Sep06
R/R rewire 17Feb07
New R/R, Installed 14Jun08
New Stator installed 10 Jun08
Maintenance Free Battery 12Jan08
21480 Miles
VROC #8542
Sky Rider is offline  
post #7 of 15 (permalink) Old 08-10-2008, 04:44 PM Thread Starter
 
Join Date: Jun 2008
Posts: 17
iTrader: (0)
 
I replaced the wires, wire ends and plugs about 6 weeks ago....which way do the small wires going to the ignition coils need to be? maybe i have one of them backwards.
nicko915 is offline  
post #8 of 15 (permalink) Old 08-11-2008, 07:47 AM
and the Adventure Cycle
 
hyperbuzzin's Avatar
 
Join Date: Jun 2004
Location: Western PA
Posts: 6,138
iTrader: (1)
   
If you're rebuilding the bike, I would think you have done this, but I'll ask anyhow...... have you looked at the air filters lately?


AKA: Tim & 'The Adventure Cycle' VROC #24567, NEVROC, SteelCity VROC


"When life throws you curves,
Aim for the apex."

Author Unknown
hyperbuzzin is offline  
post #9 of 15 (permalink) Old 08-11-2008, 09:51 AM
Members who have donated towards server costs
 
750Doug's Avatar
 
Join Date: Apr 2008
Location: S.E. Michigan
Posts: 2,850
iTrader: (10)
   
Check both vent lines too. I don't recall the exact details, and I hope somebody will fill that in, but one of the vent lines, if it gets straight air fed into it just the right way, it will bog the bike. A few people here have had the problem, corrected the vent line, and resolved the issue.

One of the lines needs to be plugged into the back of the air filter housing, and the end of it should be cut at an angle so it doesn't bottom out flat against the housing either. This vent line is the one that comes off the "T" between both carbs.

Last edited by 750Doug; 08-11-2008 at 09:58 AM.
750Doug is offline  
post #10 of 15 (permalink) Old 08-11-2008, 05:48 PM Thread Starter
 
Join Date: Jun 2008
Posts: 17
iTrader: (0)
 
The air filters are brand new, so that's not the problem and vent line is where it should be with an angled cut...

I rode it for 15 minutes yesterday to get it hot, brought it home and took out the plugs. The rear plugs were tan/brown, not very wet...looking like it's burning too hot and the front ones were black...I get confused at what plugs are supposed to look like...but I'm pretty sure it's neither of what I have going on. Any ideas?
nicko915 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