I purchased an 04 YFZ from a friend nearly a month ago. The bike has an LRD pro 4 series exhaust on it, I believe (or along those lines), with a K&N, no airbox lid, and supposedly has a port and polish, and has new clutches, not sure on brand. I've been doing the standard maintenance bit as well as riding it here and there, trying to get it squared away before I really get into it.
I've done an oil change, replaced spark plug, header gasket, cleaned air filter, carb and installed new accelerator pump and did the zip tie mod. The primary issue with the bike is that it has been running lean since before I purchased the bike. While cleaning the carb, I noted the jets and clip position on the needle:
168 main, 48 pilot, 50 leak jet, and 5th clip down on the stock needle, I believe NDSR, and the fuel screw was 7/8ths of a turn out. I know he started messing with it as he claimed he noticed a lean pop, though I'm not entirely sure he knew what he was doing. The whole thing has been lean through the whole range for me.
Today I swapped out to a 170 main, kept the rest of the jets the same, moved the clip to the 6th position, and installed a fuel mixture knob, that I set at 2 turns.
Things have improved moderately, though it's apparent it is still running lean, especially once the engine has gotten hot. Elevated idle once hot, will return to normal if I pull it down with the clutch. Once I touch the throttle again, it's back to being elevated. I tinkered with the fuel knob during the process and noticed no changes regardless of the direction I turned it. The header was glowing read, noticeably so through the header wrap when I shut her off.
I let it cool and pulled the plug to check it out, but I'm not the best at reading plugs, so I've uploaded a few pictures to get your opinions.
Also, I noticed the oil before my first oil change (first thing I did before I rode it) was a gray color. My friend always ran 20w-50 Yamalube through it, and I replaced it with the same, with a new filter, and the oil immediately returned to a shade of gray, though a bit more transparent do to not having so much carbon build up. I've also uploaded a picture of the oil on the dipstick, as I'm unsure of whether or not this something to be worried of, or if it's simply new clutches breaking in.
Thanks.
I've done an oil change, replaced spark plug, header gasket, cleaned air filter, carb and installed new accelerator pump and did the zip tie mod. The primary issue with the bike is that it has been running lean since before I purchased the bike. While cleaning the carb, I noted the jets and clip position on the needle:
168 main, 48 pilot, 50 leak jet, and 5th clip down on the stock needle, I believe NDSR, and the fuel screw was 7/8ths of a turn out. I know he started messing with it as he claimed he noticed a lean pop, though I'm not entirely sure he knew what he was doing. The whole thing has been lean through the whole range for me.
Today I swapped out to a 170 main, kept the rest of the jets the same, moved the clip to the 6th position, and installed a fuel mixture knob, that I set at 2 turns.
Things have improved moderately, though it's apparent it is still running lean, especially once the engine has gotten hot. Elevated idle once hot, will return to normal if I pull it down with the clutch. Once I touch the throttle again, it's back to being elevated. I tinkered with the fuel knob during the process and noticed no changes regardless of the direction I turned it. The header was glowing read, noticeably so through the header wrap when I shut her off.
I let it cool and pulled the plug to check it out, but I'm not the best at reading plugs, so I've uploaded a few pictures to get your opinions.
Also, I noticed the oil before my first oil change (first thing I did before I rode it) was a gray color. My friend always ran 20w-50 Yamalube through it, and I replaced it with the same, with a new filter, and the oil immediately returned to a shade of gray, though a bit more transparent do to not having so much carbon build up. I've also uploaded a picture of the oil on the dipstick, as I'm unsure of whether or not this something to be worried of, or if it's simply new clutches breaking in.
Thanks.