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Discussion Starter #1
I ride a VN750 2006 with 8000miles. I recently got a leak of coolant. After some digging I found and confirmed the leak to come from the front cylinder: gasket between engine block and cylinder at the rear of the gasket (between the 2 cylinders at the bottom of the V).

I have removed the engine and I am in the process of removing the cylinder to replace that gasket.

If it happens to be a bad gasket then that would make sense (will know soon). But I am still puzzled to have this issue with so few miles. I am wondering if it might be the consequence of some other issue: coolant excess pressure, temperature gauge defective,....?
 

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While those things are possible, many of the later models of the VN 750 had crappy cylinder base gaskets from the factory. The gasket usually fails near one of the bolt holes.
The aftermarket gaskets are heavier than the ones I had originally. I had a similar leak a year ago.
Once that engine is out it's time to think about the stator too. Maybe do the mod to make it changeable without pulling the engine.
If you want to do the earshave, now is the time. The carbs can come off for rejetting, and you will save time and irritation getting the airbox back together.
There is a little sintered metal filter in the head that should be replaced once you take off the valve cover. Be sure and look for this in the manual to see what I'm talking about.
I doubt that you had excessive pressure in the system. My money is on the gasket.
Bronson
 

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What year did this start happening? I have an '02 with 70,000+ miles which has never leaked. With only 8000 miles, it is most likely a defective gasket. Kawasaki never took the Vulcan 750 seriously, and sold it completely unchanged for 22 years with nothing but different colors. The used the tooling till it wore out, then discontinued the model. It is likely new parts will be made with that same worn out tooling, that would explain why my original cam chain tensioners lasted 15,000 miles, but the new oem ones I replaced them with only lasted 10,000 miles. I was not aware you could get aftermarket gaskets. I am about to pull the front bevel drive gearcase on mine, so I can get the driveshaft out for maintenance. I have never had the driveshaft out, thought I would do it right this time. It is a lot easier to remove that gearcase than the swingarm. Was going to use a stock gasket. I just replaced my clutch with a new Kawasaki gasket, and it seemed fine.


I think there is a design problem with the coolant passages between the cylinders and the bottom end, they come too close to the edge. There just isn't enough room for gaskets with enough material to properly seal these passages, and being so narrow, it would be easy to deform the gasket while installing it. As far as I know, this issue exists with all years of the Vulcan 750.
 

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Discussion Starter #6
Almost there

All,

Thanks for your replies. Very useful. some a bit cryptic for me yet. But I'll come back to them later on.

I have taken the engine out of the motocycle, removed the engine cover, the middle block (i think it is the piston block) and not i am trying to remove the engine block (the one at the bottom). I needed a special tool to pull the fly wheel of the alternator. It supposed to be delivered home this coming week (18 mm x 1.5 mm RH bolt). Still to do some work after that but i think it should come up easy now.

As i am presently thinking of re-assembling the whole i am looking for engine gasket kits. thought you might point me to some places on the web.
 

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Discussion Starter #8 (Edited)
A new step in my vn750 engine disassembly

I finally was able to remove the alternator flywheel. I didn't know that I had to hammer the rotor puller so strongly.

Found the leaking gasket. Yeahhh..... The corners were cracked. I also noticed that one of the coolant-tunnel-ends had a deposit of greasy gunk.

Here I have attached 4 pictures showing this.

My next step is to order the gaskets. Thanks again for your input, it helped me.
 

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I finally was able to remove the alternator flywheel. I didn't know that I had to hammer the rotor puller so strongly.

Found the leaking gasket. Yeahhh..... The corners were cracked. I also noticed that one of the coolant-tunnel-ends had a deposit of greasy gunk.

Here I have attached 4 pictures showing this.

My next step is to order the gaskets. Thanks again for your input, it helped me.
Nice work.

It seems some of the rotors are on there really good, and some come right off. Mine popped off with very little torque, and had a satisfying "pop" sound. Glad your venture was successful!
 

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Discussion Starter #10
While those things are possible, many of the later models of the VN 750 had crappy cylinder base gaskets from the factory. The gasket usually fails near one of the bolt holes.
The aftermarket gaskets are heavier than the ones I had originally. I had a similar leak a year ago.
Once that engine is out it's time to think about the stator too. Maybe do the mod to make it changeable without pulling the engine.
If you want to do the earshave, now is the time. The carbs can come off for rejetting, and you will save time and irritation getting the airbox back together.
There is a little sintered metal filter in the head that should be replaced once you take off the valve cover. Be sure and look for this in the manual to see what I'm talking about.
I doubt that you had excessive pressure in the system. My money is on the gasket.
Bronson


You were right. The problem is the gasket. See pictures in the thread.
 

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Discussion Starter #11
next step

Have ordered gaskets. Replaced the bottom one (the one which was leaking) and added silicone based sealant. I felt that it would seal better at the price of the extra thickness. Then re-assembled the piston cylinder followed by the top cylinder part using a new metallic gasket. Torqued everything according to specs.

Then I thought my HLAs might have air in them since I moved the cylinder top around too much (not knowing). So now I am in the process of air bleeding the HLAs. Need to buy kerosene.
 
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