Kawasaki VN750 Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1
hello I’m Mario
I really love motorcycle and have been riding for a while. Recently I decide to look for a project bike. Scrolling through facebook market and I found a non running 2005 Kawasaki Vulcan 750 for $500 nothing missing... thought about it and wasn’t sure if it was for me because I’m 6’6”.. Decided to buy the bike and rebuild it for a gift to my father

Before finding the website I fixed the following

-Seized front brake caliper piston(rebuilt both)
-replaced front brake pads
-new battery
-rebuilt the carb
-new fuel hose lines
-new petcock
-new front tire
-acid in gas take to clean out rust
-new thermostat
-oil change
-new spark plugs


Issues I’m having
-opened the brake system up to rebuild the caliper piston and introduced a lot of air into the system. Taking forever to bleed it out
-I’m tryna find the right setting for the carb. I feel like I’m running to rich. At times I have white smoke coming out. But from reading a few of the topics it might be that I didnt calibrate the spark plugs right.
-a knock that comes and goes. I hear it mostly when I just start it

As of right now that’s the only issues I have.
Gonna register the bike to my name this weekend so hopefully I can do a little test riding

Any tips tricks or advice is greatly appreciated
Glad to join the vn750 crew
 

·
Registered
Joined
·
8,237 Posts
Welcome to the machine!

Can maybe try gravity bleeding overnight for the brakes.

White smoke might be gas vapor, like maybe a stuck carb float.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #3
Welcome to the machine!

Can maybe try gravity bleeding overnight for the brakes.

White smoke might be gas vapor, like maybe a stuck carb float.

Yea I’ve tried to do gravity feed by keeping the brake lever pressed down to throttle for 2 nights and didn’t work. I tried to reverse feed the oil didn’t work out the best so I ended up doing the basic press brake and open bleeder valve. Started to feel something but didn’t get to finish till I got full pressure

When I rebuilt the carb the only thing I didn’t replace is the diaphragm. Not sure why it would be sticking unless it’s a problem with the old diaphragms. Or could it be the throttle slide?
 

·
Premium Member
Joined
·
3,027 Posts
I have gravity bled the brakes on every one of the 50+ bikes I've owned. You just loosen the bleeder screw(s), remove the master cylinder cover, don't touch the brake lever, and let it dribble. Stay next to the bike. Pull up a chair and open up a beer if necessary. It may take a while. All you have to do is make sure the master cylinder reservoir does not run empty and let air into the system. If it does, you will have to start all over again. I flush out and refill the fluid on all 6 of my bikes every couple of years. Never had a problem doing it that way.

As far as the rest of it, is the bike stock, meaning does it have the complete stock intake and exhaust system on it? If not, you're on your own. There are an infinite number of variables. It will all be trial and error. IF it is one of the few that is still stock, then the stock carb jets and pilot air screw settings should work, although removing the EPA plugs and turning the pilot air screws out a bit will definitely help. You said carb, there are TWO carbs, which share a common float chamber assembly. It is a very unusual design. There are several places where it is not difficult to make a mistake when reassembling them. Besides the main diaphragms, there are 2 more diaphragms, one on the side of each carb. These control the coasting enrichener. The EPA set the mixture so lean on these carbs that it caused the engine to backfire on deceleration, requiring a complicated system to richen the mixture on deceleration. I found those coasting enrichener diaphragms MELTED on mine once, likely due to ethanol gas.

Also, there is at least one, maybe two systems that need to be removed is they are still on the bike. One is the PAIR system, which all VN750s have, and if you have a California model, there is also the evap system. Remove EVERYTHING, then cap/plug anything these EPA systems connected to. There is a lot of information on here explaining on how to get rid of this EPA garbage. Also take the gas cap apart, and remove everything inside. There is yet another diaphragm valve in there. The tank MUST be vented to the atmosphere to work properly.

Spark plugs are not calibrated, they are gapped. They need to be gapped properly, and they need to be CLEAN. The VN750 has a weak ignition system, and it doesn't work well, if at all, with dirty plugs.

Unless you have a serious internal engine problem, an engine knock sound is usually the result of defective cam chain tensioners (every VN750 cam chain tensioner ever made was defective as far as I can tell) and the cam chains are loose, or the counterbalancer dampers are deteriorated and the balancer is hitting the case. Either one can destroy the engine if not fixed pronto.

White smoke has nothing to do with running too rich. That would cause black smoke and a strong exhaust smell. White smoke is either oil burning, or steam escaping from the cooling system. If you have steam from the cooling system coming out the exhaust, you have an internal coolant leak from somewhere. Look at the oil sight glass. If you just changed the oil, all you should see is clean oil. If it looks white or milky, you may have coolant in the oil, or it could just be from condensation forming inside the engine, and will quickly burn off.

What was your reason for replacing the thermostat?
 

·
Registered
Joined
·
8,237 Posts
White smoke has nothing to do with running too rich. That would cause black smoke and a strong exhaust smell. White smoke is either oil burning, or steam escaping from the cooling system. If you have steam from the cooling system coming out the exhaust, you have an internal coolant leak from somewhere. Look at the oil sight glass. If you just changed the oil, all you should see is clean oil. If it looks white or milky, you may have coolant in the oil, or it could just be from condensation forming inside the engine, and will quickly burn off.
Jerry, most often a rich condition causes black smoke. But an extreme rich condition will get you white gas vapor. Rarely seen on most gas engines, but relatively common on this one. It could be due to the goat's belly, providing heat for the exhaust of a flooding cylinder that isn't firing at all.

A flooded diesel that doesn't fire, produces white vapor also.

Of course if the white smoke smells like antifreeze instead of gas, that's a different problem.

Mario, as Jerry said, the float is different from the diaphragms. It controls the level of fuel in the carbs, if it sticks, the extra fuel can flow to the cylinders, making it rich.

Does the vapor smell like gas or antifreeze?

Note about the appearance of the oil in the sight glass: The oil always looks milky on this engine if it is started then shut down before it has fully warmed up. So check the color before you start it.
 

·
Registered
Joined
·
8,237 Posts
Just to add to my earlier post:

There's several posts here about VNs with fuel dripping out of the pipes along with white vapor, carb float was stuck.

It's also somewhat rare for a stuck float on a bike to fill the cylinder(s) and crankcase with fuel, but this one does it very easily. Many bikes will just dump the fuel out the overflow. Come to think of it ... Do these carbs have an overflow? I forget, but don't remember dealing with it either. I know there's the drain, but ... ??
 

·
Registered
Joined
·
8 Posts
Discussion Starter #7
Read through all the advice thanks guys. I’m currently on a trip for a week and when I get back I’ll work on the bike and update you guys

Thanks again
 

·
Registered
Joined
·
8 Posts
Discussion Starter #8
I have gravity bled the brakes on every one of the 50+ bikes I've owned. You just loosen the bleeder screw(s), remove the master cylinder cover, don't touch the brake lever, and let it dribble. Stay next to the bike. Pull up a chair and open up a beer if necessary. It may take a while. All you have to do is make sure the master cylinder reservoir does not run empty and let air into the system. If it does, you will have to start all over again. I flush out and refill the fluid on all 6 of my bikes every couple of years. Never had a problem doing it that way.

As far as the rest of it, is the bike stock, meaning does it have the complete stock intake and exhaust system on it? If not, you're on your own. There are an infinite number of variables. It will all be trial and error. IF it is one of the few that is still stock, then the stock carb jets and pilot air screw settings should work, although removing the EPA plugs and turning the pilot air screws out a bit will definitely help. You said carb, there are TWO carbs, which share a common float chamber assembly. It is a very unusual design. There are several places where it is not difficult to make a mistake when reassembling them. Besides the main diaphragms, there are 2 more diaphragms, one on the side of each carb. These control the coasting enrichener. The EPA set the mixture so lean on these carbs that it caused the engine to backfire on deceleration, requiring a complicated system to richen the mixture on deceleration. I found those coasting enrichener diaphragms MELTED on mine once, likely due to ethanol gas.

Also, there is at least one, maybe two systems that need to be removed is they are still on the bike. One is the PAIR system, which all VN750s have, and if you have a California model, there is also the evap system. Remove EVERYTHING, then cap/plug anything these EPA systems connected to. There is a lot of information on here explaining on how to get rid of this EPA garbage. Also take the gas cap apart, and remove everything inside. There is yet another diaphragm valve in there. The tank MUST be vented to the atmosphere to work properly.

Spark plugs are not calibrated, they are gapped. They need to be gapped properly, and they need to be CLEAN. The VN750 has a weak ignition system, and it doesn't work well, if at all, with dirty plugs.

Unless you have a serious internal engine problem, an engine knock sound is usually the result of defective cam chain tensioners (every VN750 cam chain tensioner ever made was defective as far as I can tell) and the cam chains are loose, or the counterbalancer dampers are deteriorated and the balancer is hitting the case. Either one can destroy the engine if not fixed pronto.

White smoke has nothing to do with running too rich. That would cause black smoke and a strong exhaust smell. White smoke is either oil burning, or steam escaping from the cooling system. If you have steam from the cooling system coming out the exhaust, you have an internal coolant leak from somewhere. Look at the oil sight glass. If you just changed the oil, all you should see is clean oil. If it looks white or milky, you may have coolant in the oil, or it could just be from condensation forming inside the engine, and will quickly burn off.

What was your reason for replacing the thermostat?
I forgot to mention that the bike has not been ran since 2015 😅

I will try to do the way you said to bleed the brakes when I have a few hours to spare
Today I gapped(calibrated) the spark plugs to .35 gap. Not sure where I read it but remember reading that it was .35. After that I started it up. Let it run for a little while and I noticed that it was reving high so I started playing with the carb some, after while it stopped the smoke. Decided to take it out and see if it would blow smoke while riding and nothing it was all good. After riding it for about 10 minutes I returned to my garage. Before turning it off I didn’t really hear the knock as much .The bike is 100% stock I haven’t shaved the ears. I don’t think I will do those modes for a while
 

·
Registered
Joined
·
8 Posts
Discussion Starter #9
Just to add to my earlier post:

There's several posts here about VNs with fuel dripping out of the pipes along with white vapor, carb float was stuck.

It's also somewhat rare for a stuck float on a bike to fill the cylinder(s) and crankcase with fuel, but this one does it very easily. Many bikes will just dump the fuel out the overflow. Come to think of it ... Do these carbs have an overflow? I forget, but don't remember dealing with it either. I know there's the drain, but ... ??
From what I remember there when rebuilding it it has a float. I think I’m the middle of both. I adjusted air mixture and fuel and stopped the smoke and the bikes runs better
 
1 - 9 of 9 Posts
Top