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Young Gun
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213 Posts
Discussion Starter #1
All right boys and girls. I've been working on a 1986 750 that I picked up cheap. It's got 21,XXX miles. It wasn't running when I got it and hadn't been for some time (last inspection sticker is from 2004). I've done a lot to it already and have made posts for various questions that come up along the way. I figured I would start one main thread on it to keep all the info together - mostly for my benefit if nothing else. This first post is gonna be a little long winded, but bear with me, just want you guys to have all the info.

SO FAR I'VE DONE:

Oil and filter change (Rotella 15w40)
Replace Air filters (OEM)
New AGM battery
Spark plugs
---I put Iridiums in my '90 vn750 and gave the '86 it's old plugs - nothing wrong with them, just got a deal on Iridiums
Coolant change (Dexcool 50/50)
Rear spline lube (Honda Moly 70)
---New o-ring
---New gear oil
Cleaned and rebuilt carbs
---Ultrasonic cleaned
---All new o-rings (except the ones behind air mix screws. I drilled out the plugs, but left them be for now)
---Replaced 1 ripped diaphragm
Relocated R/R
---Tested - I think it's bad, but multimeters are not my strong suit


ISSUES I'M HAVING NOW:

I reinstalled the carbs and hit the start button. She lives! I got the bike to idle without hardly any effort. The bike made somewhat of a squealing noise on starting that quit after a few seconds. The squealing didn't seem to have any adverse effects on operation and I couldn't tell where it came from - just around the engine. I thought maybe the starter, but the noise continued after the start button was released. I've started it a few more times since and it always squeals a little, but seems to be going away. Is this just from sitting so long?

I'm having some issues with throttle response. It will snap back closed after I open it up, but is slow and I don't know if it closes all the way. I tried to adjust the cables according to the Clymer manual, but the tighter I went the harder it was to move the grip at all. I loosened them back up to where it was. I think one reason may be that when rebuilding the carbs I had to replace some of the white plastic washers on the central linkage. I couldn't find any just like stock so I got some that were thicker and sanded them down until they worked. Off the bike, the linkage snapped back good enough, but did seem a little stiffer than before. I believe the throttle snapped back normally before removing the carbs. Anyone know where to get washers to match OEM - can't find them on ronayers.com?

There's coolant leaking where the coolant pipe meets the rear head on the left side of the bike.

I think I may have over filled the coolant a little and took some back out of the overflow tank after seeing this. The coolant leaks down onto the left exhaust and smokes once the bike warms up a little.

After the bike warms up, along with some smoke from the area just behind the engine, the exhaust starts blowing white smoke. Coolant getting in the cylinder? It doesn't smoke until it warms up.

I did ride the bike slowly down the alley just to see if it would go and stop under its own power. So far, so good.

THINGS THE BIKE STILL NEEDS:

Tires - as far as I can tell from the code on the side, these are the original factory tires (from '86? Yikes!)
New R/R? again, not real confident with electrical
Carb sync - gonna build a manometer soon
Need to check the brakes, I've never bled brakes before


All in all, I'd say it's going pretty good! Starting the bike after my first ever carb rebuild gave me a lot of hope. Everything besides the carbs I've done before on my daily ride (1990 vn750) so it was familiar already.

Let me know what you guys think! Can post more pics if needed.
 

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good work. Seems like you might have just saved this thing before it was too late. Not too sure about the White smoke, i tihnk that does mean that it is getting coolant in the cylinder(s). maybe a bad head gasket?
 

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Coolant getting into the cylinder wont cause white smoke... It will cause the motor to run rough and want to stall. And make it hard to start once turned off. It may just be burning off old oil that dried up in there. The leaking radiator tube is an easy fix, 1 8mm hex bolt holds it in. Take that out and pull it out, replace the o-ring or put some grease on it and reinstall.

Its a push/pull thruttole so it wont snap closed very fast, taking off the push cable will relieve a lot of friction and it will close faster. Or u can install a secondary spring... Theres plenty of room in there by that carbs...not.
 

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Linkmeister Supreme
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7,960 Posts
Coolant getting into the cylinder wont cause white smoke... It will cause the motor to run rough and want to stall. And make it hard to start once turned off. It may just be burning off old oil that dried up in there. The leaking radiator tube is an easy fix, 1 8mm hex bolt holds it in. Take that out and pull it out, replace the o-ring or put some grease on it and reinstall.

Its a push/pull thruttole so it wont snap closed very fast, taking off the push cable will relieve a lot of friction and it will close faster. Or u can install a secondary spring... Theres plenty of room in there by that carbs...not.
I beg to differ board917, white smoke coming from the exhaust is a sure sign of coolant burning in the cylinder. I blew a head gasket in an old Buick about 20 years ago on the way to work and there was an instant white fog bank for a block behind me.
Burning oil is usually gray exhaust.
A too rich fuel mixture gives a black exhaust.
 

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keep digging at her... us project guys got to stick together.. the more you tear up and rebuild the more you like this evil chick!
 

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273 Posts
Welcome to the site of sites for your ride!!:smiley_th

A few querries::motorcycl

1) the smoke comes out of which pipe? (right or left)

2) take the cap off the oil, and the coolant. Look down with a flashlight at the oil in the crankcase: does it look like chocolate milk? Then the coolant: is there an oily film (or sludge) at the filler neck?

3) check the pipe on the left side of the bike where the coolant is dripping: is there a hole?

The more you investigate, the better idea you will have about what is going on.....

Have fun with the checks, and let us know what you find.:beerchug:
 

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Young Gun
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213 Posts
Discussion Starter #8
1) the smoke comes out of which pipe? (right or left)
Was coming out of both pipes

2) take the cap off the oil, and the coolant. Look down with a flashlight at the oil in the crankcase: does it look like chocolate milk? Then the coolant: is there an oily film (or sludge) at the filler neck?
I'll have to check this out, I can say that the oil and coolant are brand new. The oil I drained out was dark, but not milky.

I agree Gordon, and it has a sweet smell, kind of sickening really, both the smell and the idea that coolant is burning through the cyl!
I have smelled this before when I blew hose in my car, coolant sprayed all over the hot engine and smoked. I didn't notice this smell as my garage began to fill with smoke. Could still be coolant though, not sure. Would Dexcool smell different?

How big of a deal would it be to run the bike while it's smoking? Wanting to see if it gets better or worse the longer it runs.
 

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OK. Does indeed sound like a head gasket. I am assuming here that you still have the goats' belly on the bike. If you had removed it, you would have been able to tell which one it was, so you might as well do them both.

I would not reccomend running the bike much. Right now, one of the coolant passages has found a way to the comustion chamber. the longer you run it, the worse it will get.

Long shot, but if you can get the valve covers off, try retourquing the heads. It may be that the bolts have simply come loose. Worth a try, but I am betting an engine pull is in your future.

Sorry 'bout that.:smiley_th
 

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Young Gun
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Discussion Starter #10
Aye yai yai! Picked up this bike to learn a thing or two and make a couple bucks afterward. And now... for every new thing I'm gonna learn is another dollar sunk on the project. It would be different if this was my only bike, but as a project, is it worth fixing a head gasket or should I just part it out?

Also, anyone have a list of parts needed for the head gasket job? What other stuff should I do while the engine is out. Might as well put in a new freakin stator too?
 

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If it is a learning experience you were looking for, then go ahead with the engine pull and do the heads. It shouldn't be a monumental task, as long as you have been blessed with a mechanical aptitude. These bikes are wonderful when they are running, and I personally hate to see another Vulcan ripped apart when it can be brought back to life. We are here for you, use our knowledge and rebuild a beautiful bike!!!:smiley_th:beerchug::wow:
 
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