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Discussion Starter · #1 ·
Noticed a little smoke puffing up when I came to a stop a little while ago. If you're sitting on the bike, it came from the left side, and appears to be coming from just under the seat, close to where that spark plug wire passes through. It smells like coolant. Definitely not gas. Where could this possibly be coming from? I drove a few more miles and came to a stop and didn't see any more of this.
 

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Noticed a little smoke puffing up when I came to a stop a little while ago. If you're sitting on the bike, it came from the left side, and appears to be coming from just under the seat, close to where that spark plug wire passes through. It smells like coolant. Definitely not gas. Where could this possibly be coming from? I drove a few more miles and came to a stop and didn't see any more of this.
Check the steel coolant pipe where it goes into the cylinder head, the o-rings like to leak there.
 

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Discussion Starter · #3 · (Edited)
Check the steel coolant pipe where it goes into the cylinder head, the o-rings like to leak there.
EDIT: Okay, I took a flashlight and looked up under the seat and I saw that hose and the clamp, and of course, there's a little coolant collected there. Thanks for the tip, I'll probably not tinker with it until tomorrow. Just knowing it's nothing major makes me feel better.
 

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Okay, will do. On the rear cylinder, where would I find that? Is it up under the tank, or coming out of the side of the cylinder head? Sorry for my apparent ignorance, but I've never had a liquid-cooled bike before... As you can see, there's residue from coolant splattered everywhere. Also, the coolant level is indeed low.

View attachment 54453
Put your finger where the arrow is, move toward the front of the bike about 5" to the corner of the rear cylinder head.

Gray or black steel tube approximately 5/8" diameter, running vertical into the head.
 

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Discussion Starter · #5 ·
Put your finger where the arrow is, move toward the front of the bike about 5" to the corner of the rear cylinder head.

Gray or black steel tube approximately 5/8" diameter, running vertical into the head.
Apparently you posted this response at exactly the same time I edited the comment you're responding to.

But yep, found it. And the leak is actually where the rubber coolant hose connects to that tube. I guess I might have either not tightened the hose clamp well enough, or it's sprung a leak; because there is a little bit of coolant gathered between the head and that clamp, if you follow? And it makes sense, because it only began to happen when the bike was hot and coolant was flowing.
 

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Apparently you posted this response at exactly the same time I edited the comment you're responding to.

But yep, found it. And the leak is actually where the rubber coolant hose connects to that tube. I guess I might have either not tightened the hose clamp well enough, or it's sprung a leak; because there is a little bit of coolant gathered between the head and that clamp, if you follow? And it makes sense, because it only began to happen when the bike was hot and coolant was flowing.
Should be easier to fix, just the hose clamp hopefully.

I doubled the o-rings on my tubes, and used a bit of waterproof grease, the steel and aluminum always corrode. Aluminum tubes would be nice.
 

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Discussion Starter · #7 ·
Should be easier to fix, just the hose clamp hopefully.

I doubled the o-rings on my tubes, and used a bit of waterproof grease, the steel and aluminum always corrode. Aluminum tubes would be nice.
Now that you mention it, I do recall that the upper half inch of that tube was indeed corroded. Not sure what I can reallly do about it? Maybe clean it up a bit. How is that tube attached to the cylinder head? Probably from within, I imagine. I'll be sure to snap a picture or two tomorrow when I check it. Once again, thanks for the advice. You know your stuff, that's for sure!
 

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Now that you mention it, I do recall that the upper half inch of that tube was indeed corroded. Not sure what I can reallly do about it? Maybe clean it up a bit. How is that tube attached to the cylinder head? Probably from within, I imagine. I'll be sure to snap a picture or two tomorrow when I check it. Once again, thanks for the advice. You know your stuff, that's for sure!
The tube just pushes down into the head and there's a bracket with a single bolt that holds it down.

You can clean it up and coat it, if it's not corroded too badly.
 

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Discussion Starter · #9 ·
The tube just pushes down into the head and there's a bracket with a single bolt that holds it down.

You can clean it up and coat it, if it's not corroded too badly.
Awesome info! I'll get those pics tomorrow and you can tell me if you think it's salvagable or needs replacing. It's past 11 here in western NC, so I'm off to bed. G'night!
 

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I fixed the corrosion of my parts by soaking them in EvapoRust then filling the pits with JB Weld. Lastly I painted over the dried JB Weld with POR 15 after sanding it smooth. I have used this method on some badly pitted parts on many of the other vehicles I have and it has not failed yet. When replacing the o-rings I have gone through the assortment from Harbor Freight and found some that worked. Be sure to use Vaseoline and be prepared for a leak the first time It is truly one of Kawasaki's worst design features. and one that indicates to me Kawasaki had no idea how long these bikes would be on the road.
 

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Discussion Starter · #11 ·
Awesome info! I'll get those pics tomorrow and you can tell me if you think it's salvagable or needs replacing. It's past 11 here in western NC, so I'm off to bed. G'night!
So, as soon as I removed the hose clamp, I could immediately see a small trace of coolant. As seen in the pic below. I'm just going to cut off behind where the clamp was, reattach the hose and try not to overtighten the clamp.

The metal tube wasn't as corroded as I thought. It was a little crusty, but not bad. I cleaned it off, taking care not to allow any particles to enter the tube. I've loosened the thermostat bleeder tap and refilled with coolant. Gonna take a short ride, come back and see if the problem is resolved.
 

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Discussion Starter · #12 ·
Should be easier to fix, just the hose clamp hopefully.

I doubled the o-rings on my tubes, and used a bit of waterproof grease, the steel and aluminum always corrode. Aluminum tubes would be nice.
Now that the issue with the small coolant leak is resolved, here's another one for ya:

I noticed I'm not getting great gas mileage. As of yesterday, I'd logged about 50 miles on half a tank. Also, the rear cylinder spark plugs (brand new, btw) are quite blackened and somewhat oily on the end. Both of these things indicate it's running rich. I don't think it's the altitude, but I suppose it could be. On most of my other bikes I could easily adjust the fuel mixture with an external screw. Is that feature on the VN750 stock carbs? I looked through the forums and it seems that every thread that had photos longer does. A picture would be nice.
 

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Now that the issue with the small coolant leak is resolved, here's another one for ya:

I noticed I'm not getting great gas mileage. As of yesterday, I'd logged about 50 miles on half a tank. Also, the rear cylinder spark plugs (brand new, btw) are quite blackened and somewhat oily on the end. Both of these things indicate it's running rich. I don't think it's the altitude, but I suppose it could be. On most of my other bikes I could easily adjust the fuel mixture with an external screw. Is that feature on the VN750 stock carbs? I looked through the forums and it seems that every thread that had photos longer does. A picture would be nice.
Idle air screws are blocked from the factory with a small metal plug which can be removed with a small drill bit and a pick. Just drill a hole in the cap, stick a pick in, and pull the cap out.

Attached pic is the location of the idle air adjustment screws, one on each carb.

Stock setting is fully seated, then 1.75 turns out. Preferred setting (from what I remember when I tuned my carbs) is 2.5 turns out. I am at sea level in FL, though, so if you're up in the mountains in WNC you'll likely wanna go a bit leaner.
Motor vehicle Automotive lighting Automotive tire Automotive fuel system Automotive design
 

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Discussion Starter · #14 ·
Idle air screws are blocked from the factory with a small metal plug which can be removed with a small drill bit and a pick. Just drill a hole in the cap, stick a pick in, and pull the cap out.

Attached pic is the location of the idle air adjustment screws, one on each carb.

Stock setting is fully seated, then 1.75 turns out. Preferred setting (from what I remember when I tuned my carbs) is 2.5 turns out. I am at sea level in FL, though, so if you're up in the mountains in WNC you'll likely wanna go a bit leaner. View attachment 54471
Awesome, thank you!

No wonder I couldn't find that damned screw....

The drill bit I have, but no pick. But, I'll figure something out. You're a lifesaver, ubertalldude!
 

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Discussion Starter · #16 · (Edited)
I drilled it a bit then tapped a jewelers screw driver in there and wedged it out. If you’re patient it probably can be done by hand.
I do have some extremely tiny screwdrivers, from my years in computer repair. (And let me tell you, laptops have a lot of tiny little screws inside them!) So, I'll try that. If that doesn't work, I'll pick up something from Lowe's or Harbor Freight in the afternoon.

Thanks for the tip!

EDIT: Something just occurred to me: This is the idle air screw, so it's not going to affect the issue of the bike running rich, right? I'm getting lousy gas mileage and the spark plugs on the rear cylinder are blackened and oily. The front ones actually look pretty darn good. So, is this a carb issue? Running rich means either too much fuel or too little air, right?

Makes me wonder which is my problem.
 
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