I'm trying to diagnose problems in a bike I may buy from a shopmate. I've poked around on a KLX 650 forum, but I figure it wouldn't hurt to brainstorm here, as there seem to be lots of fart smellers... uh, smart fellers around here.
The bike: The bike is a 1996 KLX 650 R. DOHC, 4-valve, plated cylinder, single. The R model is kick-only, so Kawasaki included the "KACR" which is a centrifugal weight actuated (Kawasaki) Automatic Compression Release that holds one of the exhaust valves open a hair until 500 RPM or so when the weights open and deactivate it.
My buddy hasn't had the bike long, and has been saying it needs rings since he got it. He's selling it and I want it (assuming it's not a total money pit), so I started looking into it and suspected the ACR. I pulled the valve cover, and though the pins that the centrifugal weights hinge on are worn (which is apparently common), it appears to be working properly. However, I decided to check valve clearances while there, and found that NONE of the valves have clearance between the cam lobes and the shims (bucket and shim). I pulled the cams and did a leak down test (crude without gauges) and found air to be leaking past the rings and valves, seeming worse at the rings. This was with the cams not installed and valves as closed as they could be. For what it's worth, I also did a compression test like this and got 70 PSI, but this is with no intake charge of course, so I don't really know what I should expect to see.
SO... it seems that if I buy this bike I will need rings and a valve lap if not a valve grind. My thinking-out-loud question is: should i expect that the valve seats are battered if the valves buried themselves until the gaps were closed at the cam? Should I expect that the nikisil lining will be worn and need re-plating? I've never had a bike with a plated cylinder(s), I only know that they are in theory supposed to last much longer.
could this really be as simple as a valve lap, rings, and correct shimming?
