Couple issues, might be related.. - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
VN750 General Discussion

 
LinkBack Thread Tools Display Modes
post #1 of 10 (permalink) Old 09-04-2014, 04:33 AM Thread Starter
'02 Vulcan 750, 27k
 
Join Date: Aug 2014
Location: San Francisco, CA, USA
Posts: 11
iTrader: (0)
 
Couple issues, might be related..

I posted this in my newbie check-in, but realized it'll probably get more thoughts here.

I initially thought this might be related to a fuel filter or sediment in the tank - but I'm increasing thinking it's carb or cam related.

I have an intermittent (though growing more frequent) loss of engine power. It just drops for half a second - just long enough to be noticeable. I haven't noticed a corresponding drop in RPM, but that might be due to the tach's stalk shaking around alot, making it difficult to do a fine reading while I'm riding.

When idling, the RPMs bounce around a bit (~200ish range). Not sure if that's related or normal.

What I did think was related - and made me think of a fuel filter - the engine starts to act like it's running out of gas after using only 2.5 gal. It'll even sputter to a stop. I realized a couple days ago that I didn't test it for the phantom-out-of-gas condition... It also will sometimes die when the engine is still cold. Fully open choke helps prevent this - but does not completely eliminate it.

Alternately, someone mentioned that they heard cam chain noise and that I needed to replace the chain/tensioners. Could that be the cause instead? I don't really know what to listen for, so I can't validate that it was cam chain noise.
simtel32 is offline  
Sponsored Links
Advertisement
 
post #2 of 10 (permalink) Old 09-04-2014, 09:31 AM
Super Moderator
 
Join Date: Feb 2013
Location: SW Florida
Posts: 2,467
iTrader: (5)
 
a few things to look at..

for the 'out of gas' feel after a partial tank.. look into POOGS. usually the tank vent or the vent in the gas cap is plugged.

are you saying your idling at 200? or that the idle varies by 200 or so?

My bike will occasionally 'sneeze' after running at a steady throttle position (usually barely off the idle stop, with rpms below 2k or so) for a couple of minutes. and it only does it when warm (I drive thru same school zone once in morning when bike is not fully warm, and in afternoon when it is fully warm, and that's where it does it). My tach don't change when it sneezes, its like one cylinder does it one time.

2005 VN750

Sold 11-27-17
michiganteddybear is offline  
post #3 of 10 (permalink) Old 09-04-2014, 11:00 AM
Senior Member
 
Join Date: Jul 2012
Location: South Jersey
Posts: 456
iTrader: (6)
 
Quote:
Originally Posted by simtel32 View Post
I realized a couple days ago that I didn't test it for the phantom-out-of-gas condition... It also will sometimes die when the engine is still cold. Fully open choke helps prevent this - but does not completely eliminate it.

Alternately, someone mentioned that they heard cam chain noise and that I needed to replace the chain/tensioners. Could that be the cause instead? I don't really know what to listen for, so I can't validate that it was cam chain noise.
These bikes are notoriously cold blooded, they really like to be warm before they will even out, the choke thing in the AM is completely normal.
Once the bike is fully warmed up the idle should not bounce around, if it does start looking for air leaks/bad air filters etc....

As for the Cam chain tensioners, the Automatic ones that came with this bike were kinda suspect. Most of us here have replaced them with manual ones(Wolfie makes a fantastic set). The sound your listening for if they are going bad/maladjusted is a clicking-ish noise from the engine almost like a sewing machine... but not quite.
The manual ones take all the guess work out of it remove the automatic ones one at a time. Replace with the manual ones and turn the screw in until feel tension in screw. Start the bike and continue SLOWLY tightening until the click stops and the bike does not bog down. If the engine starts to bog you went to far back the screw out in small increments until it starts running normal then set the locknut. Repeat the steps on the other ACCT and your done.
jj23 is offline  
 
post #4 of 10 (permalink) Old 09-04-2014, 11:12 AM
Senior Member
 
GloryRider's Avatar
 
Join Date: Nov 2013
Location: Atlanta, GA
Posts: 277
iTrader: (1)
 
If you want to be sure, record a video on your phone or something and post it to youtube, and paste the link here... we'll listen to it and can help tell you what it is...

------------------------------
GloryRider
Atlanta, GA
Current Ride: 1995 Vulcan 88 (1500A9)
Purchased Dec. 2014
approx. 6,800 miles

Previous Bike: 2000 VN750 "Glory"
With homemade stator
Details on stator build here

"Four wheels move the body. Two wheels move the soul"

"You live more in 5 minutes on a bike like this going flat out than some people live in their lifetime." - Burt Munro
GloryRider is offline  
post #5 of 10 (permalink) Old 09-04-2014, 03:09 PM Thread Starter
'02 Vulcan 750, 27k
 
Join Date: Aug 2014
Location: San Francisco, CA, USA
Posts: 11
iTrader: (0)
 
Quote:
are you saying your idling at 200? or that the idle varies by 200 or so?

My bike will occasionally 'sneeze' after running at a steady throttle position (usually barely off the idle stop, with rpms below 2k or so) for a couple of minutes. and it only does it when warm (I drive thru same school zone once in morning when bike is not fully warm, and in afternoon when it is fully warm, and that's where it does it). My tach don't change when it sneezes, its like one cylinder does it one time.
It varies by 200 or so. A little more stable when warm, but not perfectly steady.

The power drop that I'm talking about has no sound associated with it that I can tell - it's almost like the bike gets hit by a big blast of wind; but I've noticed it happening at anywhere from 20-80 MPH, and doesn't get hit by a corresponding blast. Wind blasts also push the bike from the front, whereas this... The bike just bogs down for half a second. Worse, it's been getting more frequent recently.


Quote:
As for the Cam chain tensioners, the Automatic ones that came with this bike were kinda suspect. Most of us here have replaced them with manual ones(Wolfie makes a fantastic set). The sound your listening for if they are going bad/maladjusted is a clicking-ish noise from the engine almost like a sewing machine... but not quite.
I went ahead and ordered a pair from TOC on Monday. Not sure when they might arrive though, I haven't heard anything. I'm looking forward to putting them in!

Quote:
If you want to be sure, record a video on your phone or something and post it to youtube, and paste the link here... we'll listen to it and can help tell you what it is...
I'll definitely record it this weekend! Thanks for the offer.

Cheers
simtel32 is offline  
post #6 of 10 (permalink) Old 09-04-2014, 03:31 PM
2014 KLR 650!
 
Goofyfoot2001's Avatar
 
Join Date: Jun 2013
Location: Tega Cay, SC
Posts: 3,359
iTrader: (1)
 
Have you ear shaved? That vent hose has to be in dead air (See the ear shave procedure post). POOGS is a definite place to start. clicking is most likely your tension er like jj said.

2014 Kawasaki KLR 650
Back to the Kawa World
Goofyfoot2001 is offline  
post #7 of 10 (permalink) Old 09-04-2014, 03:53 PM
Super Moderator
 
Join Date: Feb 2013
Location: SW Florida
Posts: 2,467
iTrader: (5)
 
Quote:
Originally Posted by Goofyfoot2001 View Post
Have you ear shaved? That vent hose has to be in dead air (See the ear shave procedure post). POOGS is a definite place to start. clicking is most likely your tension er like jj said.
and if your not earshaved, make sure the carb vent hose that goes to the right ear isn't bottoming out (cut a 45 degree angle on the end to prevent that)

2005 VN750

Sold 11-27-17
michiganteddybear is offline  
post #8 of 10 (permalink) Old 09-04-2014, 05:32 PM Thread Starter
'02 Vulcan 750, 27k
 
Join Date: Aug 2014
Location: San Francisco, CA, USA
Posts: 11
iTrader: (0)
 
I haven't ear shaved yet. I really like the look of the ear-shave, but I'm hesitant to do it because fuel economy is pretty important to me (commuter bike) and it looks like it goes down after a shave.

I'll definitely take a look at that vent hose though.
simtel32 is offline  
post #9 of 10 (permalink) Old 09-04-2014, 10:36 PM
2014 KLR 650!
 
Goofyfoot2001's Avatar
 
Join Date: Jun 2013
Location: Tega Cay, SC
Posts: 3,359
iTrader: (1)
 
You dont have to rejet so no appreciable change in mileage.

2014 Kawasaki KLR 650
Back to the Kawa World
Goofyfoot2001 is offline  
post #10 of 10 (permalink) Old 09-05-2014, 11:18 PM Thread Starter
'02 Vulcan 750, 27k
 
Join Date: Aug 2014
Location: San Francisco, CA, USA
Posts: 11
iTrader: (0)
 
No? The ear-shave procedure post says that if you change the airflow, then you have to rejet. The ear shave doesn't actually change the airflow?
simtel32 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