1980 KZ 750 twin

Bike will barely turn over with battery or kickstart .
My 250 lb neighbor could hardly make it move with the Kickstart .
Take the plugs out and it turns over easy .
Any ideas?

They are pretty hard to kick over if you are getting good compression, being easy to turn over without the plugs would indicate you have good compression. It should turn over relatively easily with starter. anything wrong with your starter?

My gut says it is starter.  However not sure why I cannot kick it.

Has your bike been sitting for a while? When I bought my 77 twin it had been sitting for a couple years. My electric starter is shot and doesn't work so I use the kicker only. At first I had to almost jump on the kicker (I only weight 150lbs) but after a few days of loosening things back up from sitting and it's pretty easy (for a big twin that is) 

with the plugs out It turns over fine with the starter and the kick start . with the plugs in Very hard to turn . My 250 lb neighbor Could not kick it .

if you are trying to kick on the compression stroke you will find it very difficult to turn the engine over. I have the same problem and Im 240 lbs.

If the starter clutch is not slipping, i would start by checking your starter motor, and ensuring you have a full battery charge.

 

I agree you should do the tests in the manual in an attempt to find what is causing the issue. I would suggest making a high current shunt to assist in finding the issue. The attached are pages from welcome to the motorcycle project and I would give a line to the pages but it is currently being revised and  not active.  I copied them down in the past and here they are