Power loss - clutch?

[Phyberoptic]

So I broke out the '78 from a winter's rest. She has 36,000 original miles all but the last 1000 put on by previous owners (2). Battery charged and fresh gas in the tank, she fires and comes to idle as expected.

Rode it down the block and it's as if the power is not getting to the wheel. I'm thinking in my head maybe one of the brake calipers is stuck so I nurse it up the driveway, pushing the beast the last 20 feet (up the incline).
I'm sure it's just the weigh and not having pushed it around for months but that effort convinced me I was correct about the caliper.

I pulled it up on it's centerstand however, and in neutral the rear tire spins freely with hand pressure and just a hint of the riding pucks in the caliper (very slight scraping noise). Sit my teenaged daughter on the rear of the seat to get the front wheel in the air and find the calipers there in similar shape... scratch head...?

So could it be the clutch? Is there a quick way to confirm that?

-=Phyber

[DGXSER]

If the engine rpm goes up but the bike speed does not, that is the clutch. If you give it gas and the engine speed stays the same, its not the clutch.

[Yard Dogg]

If the clutch slips, it's more than likely worn out clutch springs. You don't have enough miles to wear out the clutch disks yet, unless someone was really tough on it.

[JeremyL]

Mine was slipping so bad I couldn't go more than half throttle without it revving up quickly without an increase in speed. I tried the aftermarket springs a nd was blown away. I bought the bike that way and hadn't ever felt full power. Unknown miles. It was working great for about 200 miles and when I changed the oil from 10w40 to 20w50 it seemed like I slipped a little bit when in 2nd or 3rd at higher rpms for a sec but only when i was close to full throttle or wide open. But I changed it late in the fall and wondered if the cold weather was keeping the fluid cooler and thicker and made it slip. I don't know if it's oil or the clutch but I think I did the adjustment right. It was part of my original problem too, something to check if your haven't already.