Sporty over-reving


I've had my sporty for near on 16 years and have had more than a few problems with it but it's still going and I'd like to keep it doing so.
The problem started a couple of days ago, I was replacing some old rusted clips on the air supply system. I tidied a few vacuum hoses up and rerouted one going to the distributor. Finished up, bolted everything down and thought nothing of it.
The next day when I started it, it roared straight to 3000rpm and started hunting between this side 2000rpm.
I found out that I'd left a vacuum pipe off one off one side of the diaphragm on the distributor, reattached this but it's still doing the same thing. I cannot think of what has happened or what I could have done to have caused this.
Please, can anybody help?