I've got a 1990 K5 and it runs alright. I recently purchased it off of somebody that lives near sea level, I live at 3000' or so. The bike has an FMF gnarly pipe and turbine core silencer, and 175 and 60 jets. The bottom end seems a little blubbery and the top end under WOT is kind of sporratic for lack of a better word. I think it is running rich as the plug is black and a little wet. What size jets would you guys reccomend? Maybe somebody here has some first hand experience with that exhaust set up at this altitude? I was thinking like a 170, 52.
Also I just did a compression test on it without the carb on it, and I kicked until the needle wouldn't go up anymore. It got to 90 psi even. The bike was cold if that makes any difference with the rings expanding or something. Does that seem normal, because it seems a little low to me.
Any comments are appreciated, and thanks in advance for any help.