Need help with Timing Adjustment (find TDC) on 8 valve 1979 GS850G

[Dogma]

Unfortunately, life has gotten in the way of putting this back together until today, we've been preparing for my oldest son's graduation, which was yesterday, so now I should have more time for it. This bike is actually for him, and he's impatient to get it running!

So, I got it back together and checked the valve clearance. Too tight on cyl 2 & 3 but 1 & 4 seemed OK. Anyone know where the best place to get shims is? I also need to get a tool. I wish I would have checked the current shim sizes before I put the cams back in though.

Thanks for the help so far!!

I get my shims from Z1 Enterprises. I have the shim tool, and never use it. Look up the zip-tie method.