I have a 1994 Kawasaki Vulcan 88. Accelerate off idle and it shakes bad, continues through the rpm range until its a vibration, plugs don't look bad, carbs cleaned, it only has 15,300 miles on it.

I have a 94, and mine ran rough until I had a new computer control chip put in. The dealer doesnt sell then anymore, so you would need to get a reconditioned one (is that the right word?) from an auto parts store. I had to get this done twice because the first one was bad so they swapped it out. There was one more thing the former owner did to fix a rough run situation, I will post it when I find the receipt. Also, it smoothed out even more when I changed out the motor mounts. WAY less vibration. I love to drive this car now!

Hello there , if if idol is the same rpm as normal , Try looking at your engine mounts and transmission mounts , if one of them are broken , this can give bad vibration at idol .. Regards Graham ..

The vibration could be a number of things. Yes, it could be a balancer issue or it could be warped or worn clutch. Big vees put a lot of stress on the clutch, even when they are designed for it. But, yours could be 14 years old and on the original factory fitted parts.

Cleaning you air filter , fuel filter and water separator must be bleeding it might have a water in it.

Do an RPM drop test to see if you have a lazy/dead cylinder. Here's how:
http://www.youtube.com/watch?v=-TOQJIW19C8&feature=channel_page

ok buddy on the carb will be some sort of screw and idle screw turn this in 1/4 of a turn with the machine running until it idles at 1000rpm also the choke will stall the engine when warm the choke is only for cold starts get back to me more info or problems