79 KZ refurb

Been working on the bike slowly but surely. Swing arm has been lightly sanded and painted as well as a few other frame parts.
Thought I would check the valve clearances, Intakes were all .005"-.006", the exhausts were .009"-.010", one was .011", will check them again once installed.
   
Decided to remove the head and clean up the piston tops and cylinder walls, although the walls were pretty clean. Put a 50/50 mix of acetone/ATF fluid and let it seep, eventually it drained out.
Lots of carbon on the combustion chambers, and the exhaust valves. Pretty sure this bike was running rich.
After the valves were cleaned up, I put some majic marker around the valve seat to check the contact surface and turned valve by hand a few times to check the land. Happy to say there is no slop in the guides either. Think I will lap each of the valves just to give improved contact.
       
Wanted to check the spring lengths but couldn't find a spec for it in the service manual. The outers are 39.5 to 40mm, the inners were 36 or a touch under. 
Anyone out there have a spec, Cheers.
 

There's no specific free length  in the manual but on page 178 of the KZ1300 Factory Service Manual there's reference to tension at a specific height.
The Manuals can be downloaded from the "Forum" tab. You have to be logged in to see them.

KB

Wanted to ask if someone knows what material the trip reset knob is made of?
I have made a brass insert with a left handed 3 mm thread, and opened the hole on the plastic shaft to accept the brass rod.
The rod is a slide fit, so that I can glue or epoxy the brass rod to the plastic. Note I haven't pushed it all the way in for the pic.
What I would like to know is what the plastic knob material is, so I can choose the appropriate glue/epoxy, to make the brass/plastic a permanent bond.
Thanks,
Here's a few pics,

 
 

You're going to want a glue that's compatable with both the brass and the likely nylon 66. Most parts like the knob would be injected molded with Nylon 66 I would choose either 5 minutre epoxy or cyanoacrylate ( super glue). If you go the superglue route, depending on the viscosity of the superglue (some superglues have the viscosity of water) , you can likely install the insert and then put a drop of the superglue on the edge (interface) between the insert and the knob and capillary action will suck the superglue in to the joint.
Nice fix for the stripped threads by the way.

After a bit of research, apparently a good test to see what the material is to get some shavings and put into a water.
Polypropylene has a density of  0.90- 0.91 gms per cubic cm, which will float in water and
Nylon 66 or PA66 has a density of 1.13-1.15 gms per cubic cm, which will sink in water.
I had a few shavings as I needed to drill the plastic to correct depth,
Well the shavings floated, which leads me to believe that the material is PP or Polypropylene.
I scored up the brass rod with a fine file held at a 45 degree angle to create a few grooves around the lower half of the brass rod,
put some cyanoacrylate glue (superglue) along the length of the brass rod and inserted into the plastic.
A bit of the brass is still sticking out of the plastic, maybe 2 mm, I may file the excess off or just leave as is. 
Will let it dry up for 24 hours before putting it into the thread.