QuestionI have a 1984 Nighthawk CB650S I have been riding the bike for the past year and 1/2 with no problems then a few weeks ago the bike quit on me as I approached a stop light, a lot like it was out of gas (though I had a full tank), at the light I restarted the bike with no problem, started on first try, idled for about 30 sec then continued on. About a 1/2 mile later the bike started to sputter so I swithched to RES, which didn't help, I gave more throttle and it would putter up in RPMs then VROOM for a sec then putter then VROOM again, but as soon as I let off the throttle and the RPMs came back down it would begin to sputter then quit, start from momentum, then quit again without the ability to restart. I let the bike sit for a day and then it ran fine again, to work and back (about 7 miles one way, I was brave that morning), I replaced all the gaskets and cleaned the carbs and jets that weekend which I planned on doing anyway even before the problem. After completing the job I again ran successfully to work and back, but the next morning I only got about 2 miles down the road when it did the same thing as described above, only more rapidly. This time I let the bike sit for about 20 min and it started again without any problem, but I didn't dare ride it this time. I let the bike sit the day then rode it home in the evening. I have to replace my air filter, it is very dirty, actually it is about 30% clogged, plus there is a lot of oil on the filter (which looks clean) and in the air box (Which has a chocolate milk look, I observed this color right after riding it home the last time), so I plan to replace the PCV as well because I understand that oil in the airbox is a symptom of a bad PCV (I have yet to check it though). The spark plug on #4 doesn't look bad (that is the only one I have checked so far), there is a little build up around the edges but the post and electrode appear free of any grim and are ashy grey in color, but I still plan on replacing them too. Idle isn't bad but when the bike is running it smells as if it is running rich. Is it possible the bike is flooding while I am riding? and can simply replacing the air filter, PCV, plugs, and some minor carb adjustments fix this type of stalling problem? FYI: After I did the carb job I made sure the bike reved well in all throttle positions, at high RPMs some white-bluish smoke was obsered out both pipes.
Thanks for the service you provide and I will look forward to your thoughts, Ryan.
AnswerHi Ryan,
I've read your narrative, but I'm off to work now. I'll reply later tonight (after midnight). BTW...love the lengthy narrative. Thanks!
I return tech information files by email. There was no email address with your question as requested. Reply and include your email addy.
Respectfully,
Mark Shively
