Buy it, worst case if you decide you don't want to deal with it, you can get your money back out of it.

Like others have said, there's great resource of incredibly helpful people here to help you.

First of all, thanks for all the advice. I ended up taking the bike home with me yesterday so I am officially a newb now. The bike looks even better in person but definitely still needs a lot of work. The good news is it seems to have compression, shifts into gear, and brakes still seem good so far. Wasn't able to check spark (pretty fouled plug) and there's something funky with the electrical to the blinkers. The growling noise is definitely there when kicking it over, so not going to try to start it. 

I also got some more info from the guy - had been sitting for 13 years in a garage, not ridden much before that. I started disassembling and my plan is to create a parts list and get to the motor to see what's inside, then order everything and clean as needed while waiting for stuff on order.

Still buzzing from just looking at the thing, can't imagine what that first start is gonna feel like

Congratulations on your bike be sure to order new brake shoes 50 yr old shoes can and have become delaminated please do that before you ride it to be safe also can you post a video of the grinding noise 

I agree, become an owner and take it home.

Like Wes (HT1kid) said, the brake pads can delaminate. When I got my DT400 it was in running condition so I started it and took it for a ride around the block, the brakes worked fine but something told me to check them anyway. When I took them apart the front brakes were ok but when I took the back brakes apart the shoes just fell off, why and how they worked I don't know but got lucky.

Welcome and Congrats!
Love the CT's. Working on #4 now.
Plenty of Info./help here as this is a great group.
John (North East coast of Ma.)

The brake shoe issue is more common than you would think.
 

Got a video of the bearing noise with no spark plugs installed. Gonna take a look at the cylinder to see if anything’s going on there as well

Hmmm yes she's a bad case & might be beyond 'buffing out'. I wouldn't be able to stop myself starting it--but ya doing the right thing if you're going inside first. Wonder if it's had water in then parked. I'd take a guess the bigend will need eyeballing as well, so crank apart job. Thanks for the video with clear sound.

 from a damp UK.
Well done on your purchase.
Doesn’t sound great but on the plus side it does turn over.
I’d whip the cylinder off and have a look there then take the flywheel cover off and see if the flywheel has any play.
Really straight forward to strip the engine completely if you need to, with just a few special tools that I think Mark mentioned previously.
Look forward to seeing how you get on, good luck.