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Incubus, the problem child XS11 in progress, is actually running pretty darn well for a bike of uncertain pedigree who sat for an unknown period of time before being coaxed back to life. No shifting, clutch or gear problems. Will almost idle smoothly and it pulls very well at least up to 6,000 rpm, which is as quick as I will push it through the playground. Those kids just aren't quick enough to give it a true test, so I have to hold back some. When I was a kid we were in shape and could dive out of the way of motorcycles. Kids today just stand there and scream. Video games are destroying the physical fitness of our country.
But the idle... I put the Colortune on it today and I have a very pretty cobalt blue with just a hint of yellow on all four. On number 4, however, I was getting intermittent combustion. I could see it and I could hear it. I still hear it when I put the plug back in. When it fires it has a real nice color, but it doesn't combust every rotation.
The spark seems to be solid and consistent. By holding the color tune wire while it sparked, in fact, I think I defibrilated a pretty regular heartbeat. I also synched them as well I could be done at about 1750 rpm (lowest it would idle), so I expect the vacuum is even enough to produce consistent draw across all four. So I'm thinking it is fuel.
Before I pull the carbs, though, I wanted some input. It seems like the pilot circuits might be just plugged up enough to slow fuel flow enough that it has to build up in the combustion chamber before it will fire. I would not think that could happen, though, since the chamber should be vacuumed out every rotation, combustion or not. So could the pilot circuits be a little clogged leading to inconsistent fuel flow? Again, I don't see how that would work unless something was floating around loose in there.
I figure I am going to pull the carbs, but before I get started I wanted to see if anyone had any other things for me to check as long as I'll have them on the bench. Like I said, it is real close and I want to finish it off so I can fine tune it and start thinking about paint.
Patrick
But the idle... I put the Colortune on it today and I have a very pretty cobalt blue with just a hint of yellow on all four. On number 4, however, I was getting intermittent combustion. I could see it and I could hear it. I still hear it when I put the plug back in. When it fires it has a real nice color, but it doesn't combust every rotation.
The spark seems to be solid and consistent. By holding the color tune wire while it sparked, in fact, I think I defibrilated a pretty regular heartbeat. I also synched them as well I could be done at about 1750 rpm (lowest it would idle), so I expect the vacuum is even enough to produce consistent draw across all four. So I'm thinking it is fuel.
Before I pull the carbs, though, I wanted some input. It seems like the pilot circuits might be just plugged up enough to slow fuel flow enough that it has to build up in the combustion chamber before it will fire. I would not think that could happen, though, since the chamber should be vacuumed out every rotation, combustion or not. So could the pilot circuits be a little clogged leading to inconsistent fuel flow? Again, I don't see how that would work unless something was floating around loose in there.
I figure I am going to pull the carbs, but before I get started I wanted to see if anyone had any other things for me to check as long as I'll have them on the bench. Like I said, it is real close and I want to finish it off so I can fine tune it and start thinking about paint.
Patrick
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