Runs out of gas while tank is full - 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 38 (permalink) Old 07-17-2007, 07:37 PM Thread Starter
Member
 
Buck_Snorts's Avatar
 
Join Date: Mar 2007
Location: Front Range of the Rocky Mountains
Posts: 47
iTrader: (0)
 
Question Runs out of gas while tank is full

First post in a long time...

I have a '95 VN750 with 14K miles, and I took off the "Goats Belly" and installed a bypass, removed the reed valves and installed blanks and plugged the lines where needed, installed K&N air filters, and had the carbs re-jetted at the Kawi dealer. This model does NOT have the "Prime" setting on the petcock, just off, on, and res (I got into an argument with the owner of the dealership about it and had to bring it in and show him before he would believe it). I can run it to work in the mornings, when it's nice and cool, with no problems. After it sits in the sun all day, I can get about a mile from work on the way home and both carbs starve out. After messing with it for 5-10 minutes it starts up and there's no more problems the rest of the way home. I thought that it might be the diaphram in the petcock, so I removed the tank and installed a new one. No help. I've checked the vacum line to the petcock and it's sealed tight. Running it in reserve doesn't change anything. It just seems like the "O" ring on that diaphram is sticking when it gets hot outside. I've gone through my second can of Sea Foam, and noticed no change. If the screen on the petcock were plugged then it should do this all of the time...

Is there a petcock made that doesn't use a vacum diaphram that I could install? It was 100 degrees when I left work today (Boulder, CO), and I ended up sitting beside the road for 10 minutes in my leather jacket before I could get it to fire up again. Or could I modify this one to work like the old ones that would feed gas whenever it was turned to on? I hate this vacum setup!

I'll not be riding it anymore until I can get this straightened out...

Thanks for any and all help and suggestions.

Buck
Buck_Snorts is offline  
Sponsored Links
Advertisement
 
post #2 of 38 (permalink) Old 07-17-2007, 07:49 PM
HAWK
 
Ccspinner's Avatar
 
Join Date: Feb 2006
Location: Chicago land
Posts: 2,576
iTrader: (9)
 
Send a message via Yahoo to Ccspinner
There has been people having this problem, check you vent line for your tank.
It is under the cap, if it gets clogged causes a vacume in the tank and wont let fuel flow out.
In the morning the motor is heating the tank and creating pressure, once it is hot from sitting in the sun cant get any hotter, when you ride the wind cools the tank creating a vacume.
Take a straw and try blowing through the line, may also be pintched under the seat.

Chad Falstad "Hawk"
Vroc #17649
2011 HD Ultra Classic "angel"
2001 Nomad 1500 Sold March 2012
2001 VN 750 "Sold June with 2008 with 21,000""Serinity"
Ccspinner is offline  
post #3 of 38 (permalink) Old 07-17-2007, 08:12 PM Thread Starter
Member
 
Buck_Snorts's Avatar
 
Join Date: Mar 2007
Location: Front Range of the Rocky Mountains
Posts: 47
iTrader: (0)
 
Chad, I even opened the tank cap thinking the same thing, and it still took 10 minutes to get it to fire. What you are saying makes a lot of sense, so I just went out and stuck a 60 mL syringe into the vent tube and ran it in and out several times, then did the same with the vent holes in the cap itself, and both were clear. I still think it's the diaphram "O" ring sticking. I can squeeze the vacum line and feel the vacum pulses, so that's not leaking...

Thanks for the idea, though.

Buck
Buck_Snorts is offline  
 
post #4 of 38 (permalink) Old 07-17-2007, 08:42 PM
Members who have donated towards server costs
 
borto1990's Avatar
 
Join Date: May 2007
Posts: 84
iTrader: (0)
 
my bike kind of did the same thing when I first got it a couple months ago. although I also had a problem of the idle hanging up and not coming right back down. However I noticed on hot days at the beginning of summer after work the bike would die in about the same spot a half mile from work. I realized every time it did it I didn't let it idle on choke very long before I took off. after letting it idle longer choked I never had the problem. as for the idle problem, my local kaw dealer offered to take the carbs apart for 275 bucks but couldn't gaurantee that was the problem. so after reading this site and talking with Tcat on here I opted for 2 cans of seafoam.. end result, running great for 14 bucks!
borto1990 is offline  
post #5 of 38 (permalink) Old 07-17-2007, 09:16 PM Thread Starter
Member
 
Buck_Snorts's Avatar
 
Join Date: Mar 2007
Location: Front Range of the Rocky Mountains
Posts: 47
iTrader: (0)
 
Thanks borto. I haven't had to use the choke at all since winter. At 6:30 in the morning, at about 55 degrees, it fires right up. At 3:30 in the afternoon it's between 85 and 100 lately, and it fires right up. Yet it only seems to quit on me when I leave work in the afternoon. The owners manual even says to not use the choke when it's warm out. I'd like to hear some other thoughts about using the choke, even when it's warm... You might be onto something. Anybody?
Buck_Snorts is offline  
post #6 of 38 (permalink) Old 07-17-2007, 09:38 PM
HAWK
 
Ccspinner's Avatar
 
Join Date: Feb 2006
Location: Chicago land
Posts: 2,576
iTrader: (9)
 
Send a message via Yahoo to Ccspinner
Makes sence, try the Choke a little, Have you used Seafoam?
That helps alot with Fuel related problems.

Chad Falstad "Hawk"
Vroc #17649
2011 HD Ultra Classic "angel"
2001 Nomad 1500 Sold March 2012
2001 VN 750 "Sold June with 2008 with 21,000""Serinity"
Ccspinner is offline  
post #7 of 38 (permalink) Old 07-17-2007, 10:41 PM Thread Starter
Member
 
Buck_Snorts's Avatar
 
Join Date: Mar 2007
Location: Front Range of the Rocky Mountains
Posts: 47
iTrader: (0)
 
Thanks Chad. I've used two cans of Sea Foam with no noticable results. I will give it one more try and ride it tomorrow to work and use the choke for a while. I just went out and started it and used the choke a bit. It died when I got the choke up to half closed, restarted it and it died again when it got to half closed again. That's totally different than when I was riding it to work when it was 23 degrees (I use a snowmobile suit and ride as long as there's no ice on the road or snow predicted). I guess I really don't know what to expect using the choke when it's warm. I've always just used it to get started when it's cold.

I'd still like to eliminate all of that vacum stuff at the petcock, though... I'm 59 years old and I've been riding since I was 16. The old style petcocks worked just fine as long as the screens were kept clean. Since all of this trouble, even if the choke trick works, I think I'll always be suspicious of that petcock. That doesn't make for fun riding if you're always wondering about it.
That, and it's kind of embarassing to have your co-workers seeing you pulled over to the side of the road every day trying to get your Vulcan to run...

Thanks for all of the replies folks. I'd welcome any additional ideas, as well. I'm going to get ready for bed and give it another shot in the morning.

Buck
Buck_Snorts is offline  
post #8 of 38 (permalink) Old 07-17-2007, 11:35 PM
Senior Member
 
Cheman's Avatar
 
Join Date: Jun 2007
Location: Gardnerville, NV
Posts: 195
iTrader: (2)
 
Must be somethin' goin around 'cause my '86 just started doing this yesterday. It happened to me twice after the bike sat in the sun for a few hours in the 95 degree (dry) heat here in Nevada. Let the bike sit for a few minutes and it started up again. Acted just like it was out of gas but had only gone 40 miles since filling up. I run seafoam in it. I tried opening the gas cap, switching to reserve. Nothing would work until the bike sat for 5 or ten minutes. I will try letting it warm up with the choke and see it that helps.
Cheman
Cheman is offline  
post #9 of 38 (permalink) Old 07-18-2007, 08:50 AM
Members who have donated towards server costs
 
Crobins365's Avatar
 
Join Date: Jul 2006
Location: Kennett Square, PA
Posts: 3,505
iTrader: (48)
     
I always use the choke on initial start-up - just less time in warm weather. But it does sound more like a vacuum problem - just no fuel getting to the carbs once you've started out. Have you pulled the petcock yet to see what's going on? I rebuilt Orleans' petcock and it was a mess - those diaphragms are pretty cheesy and I could see that being the culprit. It's an easy pull and cleaning job - probably an hour, tops. You might want to get a petcock rebuild kit (new gaskets, etc.) to have on hand, though, since you'll already be in there.

C
Crobins365 is offline  
post #10 of 38 (permalink) Old 07-18-2007, 10:09 AM
86 VN750
 
wwmkwood's Avatar
 
Join Date: Feb 2006
Location: Junction City KS
Posts: 227
iTrader: (0)
 
Mine does the exact same thing when it feels like it, usually when I'm in a hurry and don't use the choke. So far I've replaced the vacuum line, cleaned the tank, cleaned the vent in the cap, replaced the ignition switch, maintenance free battery, and new spark plugs. I can start it without using the choke and not have any problems but when it acts up it's a royal pain to get to refire. I think it has something to do with the orbit of the second moon around Jupitor.

1986 VN750
V force windshield
Vance & Hines
Willy & Max bags w/Kaw brackets
22,000 Miles as of 8-6-07
wwmkwood 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