Kawasaki VN750 Forum banner

1 - 15 of 15 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I just bought a 1995 Vulcan750 from a guy in New York, trailer'd it back to Jersey, put fresh gas and a battery, and it started right up. Rode it around the block a couple of times, ran strong and smooth, but then as I opened it up coming towards home, oil started spewing from the left air filter box. Does anyone know what it could be thats causing that? Thanks​
:BLAM:
 

·
Banned
Joined
·
10,354 Posts
...check the crankcase breather, or oil level too high, or obstucted oil line....

....if the oil level is too high, drain some, add some SeaFoam to the oil....run it a little, not hard....drain and change oil and filter....see if that helps....
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
I assumed there may be too much oil, put it on the center stand waited, 10 minutes for it to settle, then drained some til it was a little below the top of the glass. The breather hoses are un-obstructed, and connected to the air box. Still spews oil out of the breather hose coming from the front of the cylinder. thanks for the advice, Ive been looking through pages upon pages to see if anyone else had the same problem.[/FONT]
 

·
Banned
Joined
·
10,354 Posts
But if there is a blockage in the external oil lines (not the breathers), that would cause high crankcase pressure and spew out....try what I said with the SeaFoam and oil/filter change....and check all the lines for kinks and pinches....
Take 2 shots of whatever and call me in the morning....
 

·
Registered
Joined
·
8,453 Posts
Could be an excess of blowby from worn or broken rings, broken piston, etc.. Are you sure the power is up to par? If not, you could check compression on that cylinder.

Or, do a *cylinder short test to see if that cylinder is actually firing. That much oil in the air filter and no smoke at the pipe?

Normally I would say... Lift the oil cap at idle and fast idle to check blowby there. But, I don't know if it's normal for the VN to spew pressure there when running or not, some engines do, I've not done it on the VN. The rotor could sling some oil (do not try to touch the spinning rotor), which would be normal, but a fair amount of oil/smoke/air that increases with rpm would indicate excess blowby on most engines.

cylinder short test: remove plug wire on the cylinder, rpm should drop...replace wire, rpm should rise. You do this one cyl at a time on, say, a V8, V6 etc. while it's idling.

I've never run a VN on one cylinder either.

But in our case we'd have to pull two wires, better insulate the fingers.
*
*
 

·
Registered
Joined
·
4 Posts
Discussion Starter #6
Keeps getting worse. It did it again after I drained some oil out. was looking at posts on here and noticed one about gas getting into the oil. checked the little oil i dumped yesterday and it has gas in it(lit a match and held it above the surface it lit up) and I drained the rest of the oil and its just black gas. Changed filter, new oil, Checked oil lines, fresh gas and it did it again. spent $2000 on this bike bc it was so nice and itvstarted right up at the guys house. title has under 3kmiles and bike has 4719k even looks brand spankin new he kept it garaged, so i dnt understand why its a piece of **** if it was babied haha!
 

·
1986 VN750
Joined
·
3,255 Posts
Keeps getting worse. It did it again after I drained some oil out. was looking at posts on here and noticed one about gas getting into the oil. checked the little oil i dumped yesterday and it has gas in it(lit a match and held it above the surface it lit up) and I drained the rest of the oil and its just black gas. Changed filter, new oil, Checked oil lines, fresh gas and it did it again. spent $2000 on this bike bc it was so nice and itvstarted right up at the guys house. title has under 3kmiles and bike has 4719k even looks brand spankin new he kept it garaged, so i dnt understand why its a piece of **** if it was babied haha!
You probably have a sticky float in the carburetor letting gas just drip into the cylinder head, seeping down into the oil.

It just sounds like it may have sat a while, and needs some attention given to the carbs.

Happy to hear anyone elses ideas.
 

·
..have a vulcan good day!
Joined
·
4,508 Posts
You probably have a sticky float in the carburetor letting gas just drip into the cylinder head, seeping down into the oil.

It just sounds like it may have sat a while, and needs some attention given to the carbs.

Happy to hear anyone elses ideas.
x2 ....I agree, that's the first/most likely culprit, ThTanner has it nailed.

Floats can/do stick on a 750, especially if not a daily rider.

:smiley_th
 

·
Registered
Joined
·
8,453 Posts
Or a clogged air bleed, which sets up a siphon action out of the bowl.
 

·
..have a vulcan good day!
Joined
·
4,508 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #11
Rebuilt the carbs, cleaned tank, flushed all fluids, new fluids, fresh gas, fresh plugs, fresh oil filter, and to be extra safe put inline fuel filters off the petcock. Shes been running great with no problems. hopefully the inline fuel filters dont give me any problems. I just want them there to be extra safe that no tank rust developes in the tank again, thus clogging carbs again making me have to start all over again. thank you all for the advice/help. It was all correct and very usefull.
 

·
R/R = Relocated *******
Joined
·
628 Posts
You should make sure that you turn the petcock off when not riding. If there's a problem with the float sticking, at least you won't fill the crankcase with gas.

Sent from Motorcycle.com Free App
 

·
Registered
Joined
·
3,353 Posts
glad to hear you got it sorted out.

Where in NJ are you located? Maybe we can meet up and say hello. There are a few members in NJ...I am in the northern part of the state.
 

·
Registered
Joined
·
442 Posts
I spent days working on the carbs to get float needles to actually work as intended. I ended up replacing both needles, making a tool to lap the seats, polishing the float pivot points and also polishing the internal bore of the float seat housing. I had the carbs sat on my vice at the correct angle, fed from above and with a clear plastic tube pushed over the drain in the bottom and held up the side of the carb. When I started the petrol would just race up the tube until it was pouring out of the holes in the carb bore. As it got better it would fill and then slow right down and then slowly the level would climb until some critical level was reached and then it would rapidly overfill and flood out again. I kept at it, (lapping and polishing etc.) until it held the right hight, even with a good head of pressure. These bikes have to have good float management. If the carbs flood, even a little, there is only one place for the fuel to go and that is down by gravity into the inlet tract, past the valves and down through the rings into the engine oil.
 
1 - 15 of 15 Posts
Top