I know its not yamaha..... BUT!!

[Kopfjaeger]

  ok.it is a Gpz 500 s, 1989? i think . its red anyway. it was dropping on one cylinder at idle twist the throttle to 2 grand evens out, drinks oil. my first though was valves, as have had the valves die on my Gpz 1000 RX. dropped the head out ( bastard of a job fiddly bloody things) and then dropped a valve out for inspection. for my money they were shagged convex a bit and worn, guy at the head shop says no can be lapped so the person who owns the bike put it in, new valve seals ( umbrella shield type) and gets it acid cleaned washed and bead blasted. did a nice job. new rings as the gap specified was .07 mm and over unserviceable  and they measured .075( .08 no go .07 like a dick in a shirt sleeve) barrels back on new gaskets head back on set valve clearance inlet at .15mm ( .13 to .18 inlet) and ex at .20 ( .18 - .23). then the starter relay get going tink and not firing the person who owns the bike pulled starter motor outand has worn brushes and full of carbon so new brushes on the way.new exhaust gaskets ( only had one in ) winds over by hand ok no tight spots no clicking and feels like good compression( will test but not this week) cams measured ok ( within wear limits) and the cam follower plates were a bit worn. have to bear in mind the person didnt have a lot of cash so the only thing i havnt done is hone the bores just dropped new rings in (cringe) barrels looked ok and could see no scoring or lipping or slap marks measured them and they are original bore size. basically i am just wondering if anyone has had any experience with kwakas and if there is something else i should be looking out for i am a bit ( read abit more than a bit) worried that i didnt hone the barrells,not my descion but i dont think it will be a major problem.....one thing i noted was that no 1 cylinder was heavily carboned and no 2 was pretty darn clean.( yes i scraped them and cleaned all the carbon off.) i havnt had to replace rings on anything except my old dt 175 and that would run on diesel if i wanted..... just curious anythoughts appreciated i am confident in my own work but input always grateful.