I have a situation I haven't yet found a reference for. My ride to work is about 15 miles on 40 to 50 MPH county roads at sea level. Our lows are still dipping below 50 in the mornings. {There's something seriously wrong with wearing my winter gear in mid-June!!
} The bike is an '11 with about 2500 miles on it so far. She runs great, with only a little after-fire on decel and just a light pop on shutdown. The problem is what I think of as a "lean surge" when at a constant speed below about 50 mph, and below about 55 degrees. It almost feels like a miss, but not as dramatic as a true misfire. If I keep the choke out to the first notch {NOT full choke, what the shop manual calls the "enricher" position}, for the first third or so of the commute {when I hit the 50mph+ part of the drive} the problem stays away. If the temps are a little above 50 then I can usually leave the enricher off for the last third of the drive which is back down to 40 mph. However if the temps are below 50, especially down into the mid to low 40's, the enricher has to come back out after a mile or so at the lower speed.
So, the questions. What stage should I be looking at? Maybe just the spacer and mixture screw? Or is it normal for this engine to be so cold-blooded? Will running with the enricher out foul the plug, so long as the engine feels normal? IE: not lugging. Given the stated temps, how long would everybody expect to have run with the enricher on?
On particularly cold days I can run with the enricher out one notch even at 50+ mph for a couple of miles before she starts loading up. More normally I have to get it off as soon as I hit 50 which I'm guessing is when I'm getting into the main jet. On warmer days, 60 degrees and up, she runs perfectly with the enricher coming all the way off after only a mile or two. We've only hit 70 degrees a couple of times so far this year, and never during my commute window, so I'm not sure how fast she might warm up then. :'(
Sorry for the long winded post, and thanks for any advice!! Mark
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