Kawasaki VN750 Forum banner

1 - 10 of 10 Posts

·
Premium Member
Joined
·
1,647 Posts
Discussion Starter #1
After reading about all the single cylinder misfires and float valve malfunctions, Ursula has developed them now as well. Bike runs fine when cold in the morning but as she warms up, she misfires and runs generally crappy. No guts when passing etc. Front cylinder plugs are wet and both front and rear plugs are sooty. As the fronts are wet, I am assuming it is the one misfiring.
I have run carb cleaner through the tank and will now embark on using that vaunted substance, Sea Foam and see if this miracle substance will cure the problem without resorting to carb removal.
I have also turned the A/F mix screws to about 2 1/2 turns out on the front and 3 1/4 turns out on the rear as it was REALLY rich.
I'm also thinking of cleaning the airfilters as well. They were supposedly cleaned just before I bought the bike 4 years ago and even though it sat in the garage for those 4 years and appeared clean when I put the bike back together, it may be one of the causes of my problem.
If I end up pullning the carbs, what is the secret to getting them out from under the surge tank without bruised knuckles and much cursing? I wrestled with them when the engine was out of the bike but that was a cake walk compared to pulling them with the engine in the bike.
 

·
Registered
Joined
·
299 Posts
I dont know yet I have yet to pull them. But I have one thought try opening the drain screw and see if any junk comes out. KRAWDAD7...
 

·
Registered
Joined
·
553 Posts
Sky Rider, sounds like the rear is turned out to much. The more you turn them out the richer the bike runs.
 

·
Registered
Joined
·
63 Posts
Sky Rider said:
If I end up pullning the carbs, what is the secret to getting them out from under the surge tank without bruised knuckles and much cursing? I wrestled with them when the engine was out of the bike but that was a cake walk compared to pulling them with the engine in the bike.
Follow the clymers manual to the tee. You have to unhook the water hoses above the surge tank, loosen the thermostat housing.

Then after that lift up on the surge tank (try to pry something under it), Pull the duct hoses off. Then leave one carbs boot on the carb, and the other boot on the cylinder, I chose to leave the back one on the cylinder. After your carbs are part of the way out, unhook your throttle cables and choke cable.

Pulling them isnt that bad, putting them back in can be tricky, just make sure that whatever you do, mark the boots positions (I forgot to and that made the job harder).

Good luck, just keep patient, they will come out and go back in again. I am about to embark on 3rd time of doing it if seafoam doesn't solve my current problem
 

·
Registered
Joined
·
87 Posts
:carryflag I salute you guys and gals who have pulled your own carbs.I am a former Marine,'71-'75 and was a jet mechanic.I am not wanting to pull my carbs just yet.I will try everything on earth first.I would rather go through Marine Corps Boot Camp than pull the carbs.Not Really! There just doesnt seem to be much room in there.I am currently working on the carb cleaner in and up through the drain.Rinse with gas,spray again,Rinse.Good luck and remember that there are alot of great guys and gals out here that can lead you in the right direction.:rockon:
 

·
and the Adventure Cycle
Joined
·
6,141 Posts
LOL, I hear ya SS !
I've pulled the carbs on 2 of my dirtbikes, and I know that was a PITA!
And, that was just one carb per bike !!
I'd rather not do the Vulcans unless absolutly necessary.

Good luck with your ride Sky.:motorcycl
 

·
Premium Member
Joined
·
4,054 Posts
This is the first bike I've owned that only had 2 carbs. My cop bike has 4. I'm sure it has more room to work though. Sky rider, did you say you think the air filters were cleaned 4 years ago? I'd definitely clean them whether it's the problem or not!
The mixture screws on the carbs adjust fuel not air. Opening the screws allows more fuel into the combustion chamber on idle and low rpms. They really don't have much of an effect on higher revs. That's when the main jets take over.

Your situation defilitely sounds like floats allowing overflowing gas into the combustion chamber. Since it came on suddenly, it might just be a piece of crud stuck in there.
 

·
Premium Member
Joined
·
1,647 Posts
Discussion Starter #8
I was thinking it was the crud in the float valve as the symptoms sound like all those who have had float valve issues.
I did drain both float bowls and an equal amount of gas came out of the carbs and no noticable crud came out.
I'll re read the verses again on the A/F needle adjust and see what happens. I initially adjusted them so the thing would quit popping on decel.
I also got some Sea Foam and will try that trick before I pull the carbs.
The bike sat for 4 years in the garage with the engine out of the bike. I did pull the filters when I reassembled the engine and installed it and they didn't look dirty at all. The bike only ran 30 days after I bought it before I tore into it so the filters were clean then. I will look into cleaning them as well.
I trimmed the carb line that goes into the right ear at a 45 so it won't plug but that didn't solve the issue.
This seemed to happen when I put the tank in reserve for the first time. It may be residual rust though once I treated it with the Yamaha tank cleaner, it seemed good to go. The innards are still silver but I could have missed something. I may remove the tank (easy job) and the petcock and see if the fuel filters are clogged as well.
 

·
Registered
Joined
·
63 Posts
Sky Rider said:
This seemed to happen when I put the tank in reserve for the first time. It may be residual rust though once I treated it with the Yamaha tank cleaner, it seemed good to go. The innards are still silver but I could have missed something. I may remove the tank (easy job) and the petcock and see if the fuel filters are clogged as well.
This is when my problems started also, good luck to you. Run the seafoam. Clean the tank. If you have something floating in your float needle seat though or clogging your jets you will have to yank the carbs.
 

·
Premium Member
Joined
·
1,647 Posts
Discussion Starter #10
Took her for a spin this evening. Put about 20 miles on her and she ran fine. I did put the Sea Foam in and readjusted the needles to 2 1/2 on both as per the verses. She still pops some on decel but it's livable. If I experience it again, I'll probably have to bite the bullet and yank the carbs for a thorough cleaning. Blech!!
 
1 - 10 of 10 Posts
Top