Hello all, I've been having an issue with my '97 Seca II. When coming back down to idle at a stoplight from a highway run @ 4-4.5k rpm, sometimes it hangs at 2k for a little while and then drops to 1200 or so. Not really a problem as it usually drops down after a little while or if I let the clutch out a little bit, then it'll stay at the 1200 rpm or so. Then sometimes while it's idling higher I'm getting a "blat-blat" or popping exhaust sound rather than the smoothish idle note that it normally has.
I borrowed an IR temperature gun and checked the header pipes temperature where the pipes curve down, #1~ 250, #2~500, #3~600, & #4 ~500*F. 1 looks like it's too rich and 3 looks like it's too lean. From the last time I cleaned the carbs, I had set the idle mixture screws all the same, 2 turns out, so I changed #3 to 3 and #1 to 1 turns out. Then rode it to work today and checked it again tonight. Now 2, 3, & 4 are around the same ~500. However 1 is still at ~250 or so. Since adjusting it didn't seem to make a difference, I then changed it's mixture setting back to 2 turns out. I pulled 1's spark-plug, it's grey not brown nor black either (like I would have expected) and has a small spark. I then checked #4's spark plug, since it had measured fine, however it was darker than #1's and it also had a small spark.
It starts up okay, and seems to run okay other than the previously mentioned idling issue.
I'm curious if any of you have any ideas/suggestions?
I also found that my fuel petcock is seeping fuel around it's turning handle so that's something else I'm going to replace.
header pipe temperature differences
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TonyKZ1
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- Location: Marble Hill, MO. U.S.A.
Last edited by TonyKZ1 on Tue Jun 28, 2016 7:35 am, edited 1 time in total.
1997 Yamaha Seca II - mostly stock, Racetech upgraded forks, FZ6R rear shock, Oxford Adventure Style Heated Grips, a Scottoiler vSystem chain oiler. My Mileage Tracker Page.