First of all how do I know if my Compression release valve is even working? Currently I'm trying to get my 1977 dt400 started after doing a vape ignition upgrade to it. She definitely has high compression as I can barely kick it. Takes all my power to even get through one kick. After 2-3 kicks I take a second to get my breathe back. I'm a 26 year old man this bike shouldn't be so hard to kick. I'm just curious if the compression release is not adjusted right or even working at all. Does anyone know how to adjust and verify the unit is working? 

Remove the round rubber cover, at the front of the cylinder, that covers the decompression valve - the cover can be slid up the cable and out of the way. Then look at the valve and see if the cable is actuated when the kickstart is operated - you can remove the spark plug to make this action easier. If it is pulling on the valve, then it could be that hole itself is blocked with carbon. The valve can be removed and the hole cleaned - maybe wait for others to comment on the best way to do this.

Perfect so I was able to take a look and it seems the cable was working correctly when I move the kick starter and released when I let go. Seemed to slide back and forth smoothly. I took out the spark plug and put just a couple drops of 2 stoke oil in and turned it for 5 or so minutes since the bike hasn't been ran in a long time. Was turning over nice and smooth until I put the plug back in and it became super stiff again. I hope its just some carbon I can clean out like you mentioned!

How hard was it to kick before the VAPE installation?

Short answer- had a stuck engine at one point, has always been hard to kick. It is noticeably easier than previously but still super stiff.

Here is the whole background on the bike. Two years ago I found the DT400 in my girlfriends grandparents garage. It was covered in dust and her grandpa said it hadn't been ran or touched in 8 years. The motor was stuck, gas tank rusted, and a mouse nest in the airbox. He figured the bike was a total loss and didn't mind if I tinkered with it. I was able to remove the sparkplug put some oil in and rocked it back and forth, also did some light pushes on the kick starter. I was able to break it free. I cleaned out the rats nest put in a new oiled filter. Took out the carb and cleaned it. It has a couple small ports I believe still may be blocked. ( I would like some guidance on how to get this carbs full cleaned). I took off the gas tank and put in some bolts and vinegar. Shook it and got it surprisingly cleaned. 15 min wash out with soap and water blew it out with air hose then shook some 2 stoke oil in before reinstalling. At this point I was trying to get the bike to start for the first time. It was hard to kick! I taped a board on the bottom of my boot to kick it. I messed with the carb adjustments and after 50 kicks of trail and error the bike started. I was able to get it to idle. I only really got to ride it for two days. The bike would sometimes die when shifting into first and not because of user error haha. It was sputtering through the rev range almost the whole time I was able to ride. Then the one time I was riding it got it through the gears was in 3 I believe and the bike just died. I pulled in the clutch got it to a stop and after 5 or so kicks it started back up again and I rode it a few blocks back to the garage. At this point I ordered the new ignition system from vape. That was last fall. I just got it fully assembled. I believe I have it timed correctly. I get spark when I kick it over, air box has clean filter, has fuel in the tank. But wont start. It doesn't back fire or kick back. Just pretty hard to Kick. I don't use the boot anymore to kick it but still stiff. One other thing is I drained the oil tank before I took it off and I was reading the manual last night and it stated it needs to have the line bleed. I would like some advice on doing this as well. Do you think air in the oil line is causing the carb not to work? I was thinking it would still get the gas and should start but its not starting and I'm not sure.

Just removed the decompression valve. The hole wasn't fully blocked but did have a decent amount of build up. I scrapped out what I could. Does anyone know how deep the hole is? I put a little piece of metal wire through the hole but it barely goes in.

Update, the hole goes all the way through to the cylinder. I took the top of the head off and tried jamming the wire in through both sides and still was full of carbon. I ended up using a 1/16 inch drill bit and it went right through the carbon and now I have a nice clean hole!

Greetings from Tennessee. 
   When you get your bike running be sure to change
    Your brake shoes 30 yr old shoes can and will delaminate for your safety 

The passage that goes to the exhaust port may also be blocked. I've used a stiff wire, like a throttle spring out of a mikuni carburetor, to clean that passage.

To remove the valve i think the head has to come off to get at it?.
Possible the hole to the cylinger is blocked with carbon which you'll see with the valve out.
Also possible the hole from valve to the exhaust port outlet could be blocked too.
You can clean that one from bottom to top & can't get at it up top as had a bunged hole.
Comes down on a slight angle so a long drill could be carefuly run up there from below.
You'll feel the difference between working & not working by hooking the cable off the valve arm then push the kick start lever through buy hand or foot then hook it up & do the same to note the difference.
Often can hear a sort of rush of air & will feel soft-ish on compression when operating.--Thinking back close to 50 years lol.
The earlier 360's had a handlebar lever.