Strong vibrations (older bikes)

Hi guys, I've ridin a few older bikes (1980's) that have had strong vibrations in the handlebars and tank area at around 2 to 3,000 rpms. I have riddin simlar other bikes that do not have that vibration, at all, at any RPM's.
Any ideas why? Could it be the engines not balanced properly.
My '83 shovel has very little vibrations but my 1970 shovel has a LOT of vibration in the dash area. It almost feels like the dash and speedo are gonna shake off the bike. My friends Sporto has the same vibration. I'm thinking if the motor is not balanced properly it will cause this.A little vibration is normal with a rigid mounted motor but I think my '70 has too much and i want to correct it.
Any ideas?
You guys are a wealth of information and I really appriciate all of your opinions and suggestions.
I try to learn and do all my bike's work myself. sometimes it's hard to find people that know about the awesome shovelheads that I (we) love. Some guys don't care about them. They consider them "old junk". That's B.S.
Anyway, thanks again guys.

This is not comin from the wheels or tires is it?

I don't hink its wheels or tires. It might be in the primary. I will check into the dash and tank mounts too. Thanks guys.

Remember some bikes back then viberate at certain rpms.
No two bikes were the same. The Old indy dudes knew what all caused it.
Motor mounts might be the problem too.

Had a similar vibration on my '85 Evo. Loose motor mount nuts was the problem. And they weren't even very loose.

I am going to ask an oddball question, but how is your engine set up? Are you running baffles? Do you have high compression and running lower octane gas? I am asking this because I had a similar issue on my 96 EVO Sportster. I found that my tank mounts were loose. Fixed that, but I still have that vibration. After awhile after discovering that I did a few engine modifications wrong, I addressed that with 100 ll fuel. My vibration went away. PInging and Reversion.

Stock motor except for solid lifters. No Baffles. Stock compression.
I am going to check the tank and motor mounting hardware first.
Thanks guys!

Chuck, I don't understand your last post.
It's a real bad vibration at about 2500 rpm's. Not a normal thing.
Could it be from the solid lifters?
Why would someone switch to solids? Is there an advantage to using them?

You guys figured it out!!!!! YAAAAAaaY~!!!!
Thanks, you guys F-ing ROCK!!
It was loose motor mount bolts.
I tightened them and the vibration went away. They were very loose for some reason. I think the guy that rebuilt the bike didn't use loctite. I will when I get a chance.
Unbelievable. I would have never thought of it on my own.
Thanks guys~! I really appreciate the help~!
YAAHOOOO~!

Am glad that you got it working. Enjoy the riding!!!

Those nuts have a way of loosening up. If they ever come loose again, Slather with blue locktite & torque to about 40 - 45 ft. lbs. Happy riding!

A buddy of mine has a '56 K and says after a 20 minute ride all his wife wants to do is have a cigarette and go to sleep:roflmao::roflmao:

Thanks guys.
My wife loves the vibrations from the older bikes too.