not much to the timing, it's fixed mechanically so you can't really adjust it other than maybe moving the flywheel, if it does not spin without the key, or a different cdi box. sounds like it's four-stroking like a mutha though, how's the plug look?
also, what do you mean by no decomp? is there just no lever/cable, or no valve at all? i looked at the pic of the inside of the head and it looks almost like it is blocked by a bolt screwed in maybe, but the bolt does not block the outlet to the exhaust, possibly you are loosing alot of compression through there. (edited)
