I recently bought a 1997 wit 21,000 miles on it in really good condition (appearance wise) for $1700. This is my third Vulcan 750, the first two were bought new. It is hard to recommend the Vulcan 750 as a used bike. It does have a lot of issues, both design issues and build quality issues. And it is a seriously complicated bike. A Yamaha Virago has about half the parts, and fewer issues.
1. I doubt a single Vulcan 750 had it's final drive splined lubricated at the factory, and by the time the manual recommends doing it, they are often severely damaged. I took my last new one apart about a week after buying it, and sure enough the splines were completely dry. And the supply of good used final drive units is drying up. I doubt many owners besides members of this forum know about this problem, so my guess the final drives on a whole lot of Vulcan 750s got trashed, and it is Kawasaki's fault. But it is an issue nonetheless, as a new drive unit costs about $1400. And there is no way to check it without taking the rear end apart, so you just have to take a chance. Mine look good, but I already knew that if they weren't, I had a parts bike with perfect splines I could take the drive unit from.
2. That brings up the next problem. The reason I have two Vulcan 750s is because the engine in the 2002 model was destroyed by a broken cam chain at 108,000 miles. The Vulcan 750 has defective cam chain tensioners, they wear out very quickly. I started noticing cam chain noise around 15,000 miles, I replaced the tensioners with new oem ones (not cheap) and within 10,000 miles they started to fail. There is no way to fix them, but there is an option of going with manual tensioners. I did that after the second set of oem tensioners wore out. The chain might not have broke so soon (if you can call 108,000 miles soon) if it had never become loose to begin with. I have no idea how much damage was done between the first and second times the oem tensioners failed. And that is something you will never know with a used bike. I intend to put the manual tensioners from the 2002 onto the 1997. This bike has 4 cam chains, 2 jackshafts, 4 camshafts, 8 valves, 4 tensioners (only the top ones seem to be a problem) and all kinds of guides.
3. Stators. I really don't think that stators fail on this bike any more than other bikes, but when one does fail, you have to pull the engine to replace it and that is a job and a half. Most shops charge around $2000 for this job, and if you do it yourself, you'll find out why. And many of these bikes are reaching the age and mileage where stators are more likely to fail. I have replaced one stator, and if the stator fails on my 1997, I'll probably just give up and sell both of them cheap as parts bikes.
4. Balancer rubber bushings tend to fail on this bike, and when they do the balancer sprocket will cut a hole in the left front of the engine case, destroying the case. I replaced my bushing on the 2002 when I replaced the stator at around 80,000 miles.
5. Carburetors. The Vulcan 750 has unusual carburetors. There are two partial carburetors that share a common float bowl. They are not difficult to work on once removed, but they are a nightmare to remove and even worse to reinstall, especially if you do it the proper way.
6. The VN750 has a tendency toward hard starting, warm or cold, and will sometimes start up on one cylinder, then 15 seconds or so later the second cylinder will kick in. I have no idea what causes this, but I'm sure it's carb related. They come with a PAIR system which makes the starting and running conditions worse. Fortunately it is easy to remove. If you get a CA model, and they were sold new all over the country, it will also have an evap system that also causes hard starting and rough running. It too is not that hard to remove, but some things need to be plugged and rerouted.
7. The tool box door tends to break off fairly quickly. I don't use mine. But you can tell by the engineering that went into it that it was first grade stuff, and that nmakes me worry about more important parts of the bike.
8. All is not negative. Yes, I wish I had bought a Yamaha Virago or Honda shadow back in 1993, when I got my first brand new Vulcan 750. I had no idea about it's problems until I joined first the VROC (Vulcan Riders Owners Club) and then the Yahoo VN750 group. I learned enough quick enough to prevent damage to my new bike. Then I got hooked. When the Vulcan 750, stock anyway, all mine have been stock except for accessories, is running right, it is a wonderful machine. Smooth as silk on the highway, plenty of power, a high revving redline (no, it is not geared too low, it is designed to spin) and while others might disagree with this, imo it has the best seat/riding position of any bike I've ever had. I have taken 500 mole per day trips on them, I have taken 500 miles per day for two week trips on them. You get tired and sore, but I never noticed any pain from pressure points like on so many other bikes. I just wish they could have fixed it's relatively few but very annoying issues, and kept making it.
You will need some mechanical inclination and experience to keep this bike on the road. But pretty much every one here seems to think it's worth it.
I am a motorcyclist, NOT a biker.
1997 Vulcan 750, purchased about a week ago
2006 Sportster 1200 Low
2013 Royal Enfield Bullet 500, converted to carb
2001 Yamaha XT225, heavily modified
2004 Honda Rebel 250
1979 Vespa P200E
2002 Vulcan 750 parts bike
1994 Yamaha XT225 parts bike