KZ1000 valves

I am working on an 81 kz1000 with 7600 miles on it that I picked up.
I need some help as most of my experience is from working on two stoke
bikes, sleds, and outboards.
It has been stored for years and I was told that it was backfiring
at low RPM when it was put away. The #1 and #2 cylinders are low on
compression. #3 and #4 are 160 and 165. I squirted some oil in #1
and it jumped to 220. Cleared it and tried again and got about
125.(started under 100). I only paid $30 buck for this tester as my
good one got lifted so I don't know if it is suspect. Checked valve
clearence and all valves are between .003 and .004 which falls into
tolerence. Ok so time to pull the heads and most likely the #1 and #2
cylinders.
So when I have the heads off to change the rings/pistons(7600
miles?), do I need to pull the heads apart to inspect the valves/
springs? I have heard that there was valve spring problems in these
bikes. I do not have the tools to do the entire head job and I do not
know if it needs it. Is there any way I can tell? Should I bring the
head somewhere. Again I have been racing and wrenching over half my
life just have not yet done head work on four strokes. I do not want
to invest too much into this bike if I can help it. It just picked it
up to see if my wife likes riding(two up) before I spending more cash
on a newer bike.
I would hate to put it back together only to find out I should have
done head work while it was off
any ideas?

Thanks
Josh

 

I had almost the same situation in an old KZ that was given to me. It too
sat for about 7 years outside. Anyway after cleaning the carb several times,
don't forget to remove and clear the air screw passage, it bit me as I
forgot all about it until I could not adjust the mixture. Also I had good
compression until the bike ran for a while and then I could not get any
power. Turns out the rings were sticking so I removed the head Hone the
Cylinders and cleaned the ring grooves. After that it went like a bat out of
hell
Good Luck