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Hey guys been having an issue that has me stumped so far. I have a 98 Vstar 650 with 31000 miles on it. Mostly stock as far as I know with just a cobra slash cut exhaust. I have had it for about a year and never had any issues. Now when I got to start the bike it will fire right up and idle fine but if I drive the bike for about 5 miles the front cylinder drops. It will sputter on the front cylinder and the bike jerk. I cleaned the carbs but the jets were not clogged so I also replaced the spark plugs since I have never done so. The bike ran good for about a week then the issue came right back.

I replaced the ignition coil and pick up coil to no avail. When I replaced the coils I put a new set of plugs in it. Today I checked the The compression and both cylinders came back at 120 psi. While checking the compression I did notice the new spark plus seem to have a white haze on the front plug like its running lean. I am kind of at a loss here.
 

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Curious if you found the cure.

I had an old VW beetle. When I bought the car, I got about 3 miles down the road before the engine started to loose power... and then shut off. I couldn't get it to start, so I towed it home.

I found the cause was the previous owner improperly adjusted the valves. All of the rockers were set to zero lash. Started and ran great. Then when the engine warmed up, the valves would not seat as there was no room for expansion... compression lost... engine stalled. I readjusted the valves and that sucker ran like a dream to the day I parked it.

Just a thought.
 

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Possible carb float issue. The float could be set too low in that cylinder. There would be enough fuel in bowl to run a bit but when the cylinder need more fuel the bowl has not been kept full. It's easy to misadjust the float during a rebuild, just something pretty easy to check. Keep us informed.
 
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