Wilsons Sandbox

Problem: Intermittent Missing at high speed/high rpm. Started 100 miles from Moab continued till today. Most typically the engine misses on a series of long uphill grades at interstate speeds, very irritating. Never misses around town or on the trail. So far I addressed the problem by: Opening the gas cap at speed while engine was missing; didn't help. Cleaned air filter. Took off float bowl then blew out fuel line entrance. Installed new vacuum line from carb to petcock. Checked coil for resistance then had it checked for spark; all read fine. Spark plug has less than 2k. Today I took the bike for a ride engine commenced to missing. Though the tank was full I decided to try something, I switched to reserve; the engine stopped missing immediately and ran great until.....I moved the lever back down to regular open position; in a mile or two it started missing. When I moved back to reserve it again ran fine. Repeated experiment with same results. As a final test I stayed at the reserve position and ran the bike at 80-90mph for 40 miles on a stretch of I 25 that climbs about 1200' from Pueblo to Colorado Springs. Exactly the situation where the problem would usually manifest itself. The engine didn't miss a beat. .......I've installed Skip F's petcock mod but since the problem started before the mod was added, it doesn't look like it's a factor. I don't have much experience with petcocks. (I do have a dog.) Has anyone heard of something like this? Is the main line dirty? Can't see how; it's always had a filter on it. Is it one of the O rings or a gasket? Do I need a rebuild kit? Any comments/advice appreciated. Bogdan

My greencycle has been doing this exact thing for about 8 months. I checked all the electrical lines (kick stand and clutch safety kills) and found no problems. I had the dealer look at it and even had the head mechanic cruise on my bike home/lunch breaks/where ever for three days. He stated he found no hesitations or stalling. So I picked it up and on the home low and behold it did it again. This problem really bums me out because the Harley I had seemed to be more faithful. There was a lister that said to ride it for a mile or so and open the gas tank to check if the diaphragm is cracked or not. It does have a lot of vacuum when I do that and when I first get on after it being parked for 18+ hours or so. Tried the reserve thing which has proven to do good sometimes. The other thing I tried that worked at times is very unsafe but as I approach a year and have this same problem I put safety aside (not good). Anyways, what it is, is I push down on the kick stand while the bike is burping and farting, it stalls as it is lowered, I release it and kick it up and it runs great for a short while. It does seem to stall at the same locations, usually. So, I do not have any advice but I do empathize with you. I do look forward to the day I can ride this bike and not have to constantly think and plan a place to pull over. Aloha, kahiau e14