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Discussion Starter #1
I have a 1986 Vulcan 750 with only 8,000 miles. It was dropped once (about a year ago) at low speeds, but mostly did cosmetic damage. It took me a little under a year to be able to ride again, but picked it back up a month or two ago and have been riding fairly religiously.

As a spur or the moment thing I picked it up to ride for a wedding (Like a 5-6 hour interstate ride) and on the way there noticed it blowing out a little bit of the radiator fluid. It made it there, and about halfway back the temperature went up just below the red, and I pulled over. I tried flushing the radiator and noticed the water was a bit muddy. The oil looked completely clean. I leap-frogged my way home, pulling over every 20-30 minutes when it got too hot, never in the red, but just before.

So now I've noticed a slight chugging noise is my engine, and it FEELS like I have to give it a bit more throttle to get it going (but I could be crazy). The oil looks clean after draining it and replacing it, and after flushing the radiator, the water still looks a little brown. This guy has been sitting for a year, so it's possible it's a little rust in the tank, but I'm unsure. When I put water in the Resvoire it appears white and foamy.

It still behaves the same. Slight loss of power, the temperature will hover around halfway for about 12-15 minutes, then stop slightly below the red line. When I shut the engine off, it will dump just about everything in the reserve tank. But the oil still looks clean.

So! Is this a blown headgasket?? Should I be worried that riding it for so long so close to red-line has worn out some seals?? How hard is all of this to do with a relatively unskilled mechanic armed with only a Haynes Manual and a cheap tool set??

Thanks for any help/advice you can give!!
 

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Well hmm you could have a few things going on. Do you know if the coolant(if you put in straight water it will boil and over heat) is circulating? The water pump could have failed on you, unlikely but if the coolant was dirty it could have plugged the thermostat although I would be suprised if it would go 12-15 min before overheating. If you have to do a head gasket it isn't too bad on a bike. Depending on the bike tho the motor may have to come out. I know on a virago it does because the heads bolts are very long studs so you can't lift off the heads in the frame. If you have patience and a manual you will do fine. I would prob check the water pump first.
 

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Discussion Starter #3
Thanks!

Can you recommend any way to check the water pump?? I'm not quite sure how to go about that...

It also has a loss of power, and the coolant comes out white and foamy, two things that Haynes indicated may be a sign of the head gasket. Good to know it's not too hard. I don't mind fixing stuff up on my own, but I'm always afraid I could do something wrong to my bike and make it seize up on me on the interstate... :/

Looks like I'll have to give it a shot though. I'm also worried that running it that high for the 2-3 hours home might have worn out some of the seals. So I guess it'd be good to take it all apart and do a thorough cleaning either way...
 

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the seals are tough. You would think it would mix into the oil tho. But maybe it isn't part of the gasket that went. The easiest way would be to remove a hose and start it up see if it gushes out. Kinda messy but simple. The haynes will tell you the way they want you to inspect the pump as well which is probably the proper way to measure clearnces. Something had to make it overheat a head gasket doesn't go out alone. Have you cleaned the carbs recently or checked the plugs? You could have got something sucked into the carbs and plugged up a jet that would run a cylinder lean and cause it to run too hot. I used to pull the carbs on everything I owned every pre season and cleaned the heck out of them. It was a pain at times but its worth the peice of mind.
 

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It sounds like a headgasket to me. You're pushing exhaust gas and possibly oil into the cooling system, which is what foams and dirties up the coolant. You'd have to replace the gasket and probably get the heads and jugs milled to make sure you have a true mounting surface.

the VN750 motor was pretty ahead of its time, and thus is pretty complex. the Haynes manual will walk you through the process, but you'll need a fair number of quality tools, accurate torque wrenches, and some special tools to get the job done.
 

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Discussion Starter #7
So, more to add; maybe not a blown headgasket??

I went out there yesterday just to try and check the spark plugs (What freaking spark plug size is that?!? None I have!) and check the oil etc. Just some low maintenance stuff real quickly in the afternoon. I had a quick ride around the neighborhood etc for about 30 minutes a few days ago.

And the oil level was the same. So I went and drained the water from the radiator again- pretty much clear!

It was only a 30-40 minute ride, is that long enough to notice these problems?? Is the headgasket maybe NOT cracked??

I'll be out of town this weekend, but I intend to check the pump when I get home. But what would account for the loss of power if not the headgasket??

Thoughts??
 
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