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Discussion Starter #1
so im fouling out on one cylinder of my CB350, but my carbs are jetted the same. should i back down on jet size on the side that is fowling out, or back down on both?
 

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It could be float level differences or maybe that the jets don't flow the same amounts. Try swapping carbs L to R and see if the rich side changes sides.

It could also be a worn needle jet difference or the needles themselves. Try measuring them and compare or use a caliper and check the diameter every say 10mm on one needle and while the first needle is in the caliper, slide the other needle in beside it. If it sits higher or lower in teh calipers then it's a different diameter.
 

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It could be float level differences or maybe that the jets don't flow the same amounts. Try swapping carbs L to R and see if the rich side changes sides.

It could also be a worn needle jet difference or the needles themselves. Try measuring them and compare or use a caliper and check the diameter every say 10mm on one needle and while the first needle is in the caliper, slide the other needle in beside it. If it sits higher or lower in teh calipers then it's a different diameter.
 

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Discussion Starter #4
theyre the factory keins, so i cant swap them side to side, but i can swap floats from side to side.
 

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Discussion Starter #5
theyre the factory keins, so i cant swap them side to side, but i can swap floats from side to side.
 

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Discussion Starter #8
backstory.

i stopped riding my CB350 afew months back (before it got cold) because the left cylinder wasnt firing all the time. i put new plugs, coils (a pain in the ass to find a NICE set for cheap...i lucked into this set), condenser, points and boots on it, to no avail. in the mean time i replaced the cheap emgo's with K&N's, and put on some different mufflers. yes, i know, get it running right before you modify, but i was halfway hoping that the modifications could fix the problem. when i put the mufflers and filters on it i also went up a couple of jet sizes...to be alittle safe. i found a fuse (the 15A that is in the tube shaped plastic piece attached to the battery box on the negative side) that wasnt blown, but the end was broken, but still attached. when i replaced it, it 90% fixed it, but then it started cutting out again. i pulled the plug and it was fouled out, but the other side was a beautiful golden brown. hence my running rich on one side question.
 

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Discussion Starter #9
backstory.

i stopped riding my CB350 afew months back (before it got cold) because the left cylinder wasnt firing all the time. i put new plugs, coils (a pain in the ass to find a NICE set for cheap...i lucked into this set), condenser, points and boots on it, to no avail. in the mean time i replaced the cheap emgo's with K&N's, and put on some different mufflers. yes, i know, get it running right before you modify, but i was halfway hoping that the modifications could fix the problem. when i put the mufflers and filters on it i also went up a couple of jet sizes...to be alittle safe. i found a fuse (the 15A that is in the tube shaped plastic piece attached to the battery box on the negative side) that wasnt blown, but the end was broken, but still attached. when i replaced it, it 90% fixed it, but then it started cutting out again. i pulled the plug and it was fouled out, but the other side was a beautiful golden brown. hence my running rich on one side question.
 

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Dull black, not wet, tends to indicate rich mixture leading to sooty combustion. Tends to suggest incomplete combustion. Could be leaky floats or worn jets/needles etc, different flow from one side to the other ie filter partially blocked, problem in an exhaust.

Or it could be very retarded timing on that side leading to incomplete combustion, or lack of compression on that side. or could be another electrical fault as yet undiagnosed. Fortunately even if carbs can't be swapped side to side, jets and floats and coils can.

You could try testing the compression and swap the cois from one side to the other and see if the problem shifts sides.

Then try checking float levels and if they are OK, I'd swap the jets from one side to the other. I'm trying to start with things that are easy, free and simple to test.
 

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Dull black, not wet, tends to indicate rich mixture leading to sooty combustion. Tends to suggest incomplete combustion. Could be leaky floats or worn jets/needles etc, different flow from one side to the other ie filter partially blocked, problem in an exhaust.

Or it could be very retarded timing on that side leading to incomplete combustion, or lack of compression on that side. or could be another electrical fault as yet undiagnosed. Fortunately even if carbs can't be swapped side to side, jets and floats and coils can.

You could try testing the compression and swap the cois from one side to the other and see if the problem shifts sides.

Then try checking float levels and if they are OK, I'd swap the jets from one side to the other. I'm trying to start with things that are easy, free and simple to test.
 
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