Here are some pictures of my bikes carb, 640, 2004, 33k km. I'm not absolutely shure about this, but I think it might be just slightly worn, eh?? It seems like none of previous owners ever did any maintenance on the carb. Needle worn almost in half, slide worn badly and guide even has holes worn through. Bike is running great, although I have no other lc4 around with mikuni to compare. Runs better than xt660x, but not so good as lc4 with keihin carb. When I got this bike, it was all stock except exhaust, which is some aftermarket, don't know exactly what. I did full maintenance, only carb and valves left to do. Air box is stock, with snorkel on top and closed side panel. EPC valve was still there, which I fixed just now. Main jet 152.5, pilot 45. Ordered new parts, they will arrive in two weeks, for now I put the carb back as is, took it for a ride and noticed that now it drops rpm when I twist throttle from iddle just a little bit, some maybe 2mm, twist a bit more and it runs like it should. I guess there is no point in sorting this until all worn parts will be replaced. Now, why was I telling all this.. Oh, yes, could anyone tell me dimensions of o-rings? Our dealer has a kit for about 40 EUR, but I only need those 3 rings, I could get them separately but I need to know dimensions.