Sooty saga

[motogtp]

1978 Super Sport, stock with clean carbs, 6,080 miles. Started running rough one day, like it was only on two cylinders and sure enough 2-3 plugs were sooty and 1-4 plugs were clean and wet. One coil was dead so I bought new plugs and the Cycle X optical trigger ignition and coil. Big difference! It has never pulled this hard before. However, the plugs are still black and sooty like it was running rich. So I thought, put on those air filter pods that you decided not to go with. That will lean it out a bit. No difference. Totally cleaned plugs will come out black and sooty after less than 5 miles of riding. I get a little blue smoke from the exhaust, but not much. Is it possible that I am burning oil and not running rich like I thought? Voltage regulator problem? Not sure were to go next at this point.

 

[dirtdigger]

You can get blue smoke from overly rich mixture also from the gas washing the oil off the cylinders. Fluffy soft soot is from fuel, and you get a harder and whiter buildup from oil. I would start checking float levels and plugged air passages if this problem just started as hasn't been an ongoing issue. Was it running rich before the ignition went bad? You may have some floats getting soaked and causing high float levels. Are all plugs sooty?

Have you checked charging voltage? If its charging then its not an issue.

 

[motogtp]

You can get blue smoke from overly rich mixture also from the gas washing the oil off the cylinders. Fluffy soft soot is from fuel, and you get a harder and whiter buildup from oil. I would start checking float levels and plugged air passages if this problem just started as hasn't been an ongoing issue. Was it running rich before the ignition went bad? You may have some floats getting soaked and causing high float levels. Are all plugs sooty?

Have you checked charging voltage? If its charging then its not an issue.

Thanks DD. I don't think it was running rich before. It is a fluffy soft soot. I recently bought a new battery but will check the charging system. I didn't think about the floats because all 4 plugs are sooty. Before all this started happening I took the carbs off to spray the bowls (mostly clean but with sediment in the bottom) and bodies with carb cleaner. Could the cleaner have attacked the floats and caused them to saturate?

 

[dirtdigger]

Was it spray cleaner or a strong dip solution? The carb dip is a no-no for floats, but most spray cleaners are ok on floats. Wonder maybe if one of the check balls or the diaphram for the accel pump is leaking. What did you set plug gaps too? Are they the standard heat range plug?

Your blue smoke could also be worn valve guides which are a big issue on the ss F2 motor.

 

[motogtp]

Was it spray cleaner or a strong dip solution? The carb dip is a no-no for floats, but most spray cleaners are ok on floats. Wonder maybe if one of the check balls or the diaphram for the accel pump is leaking. What did you set plug gaps too? Are they the standard heat range plug?

Your blue smoke could also be worn valve guides which are a big issue on the ss F2 motor.

Just a spray cleaner. Standard heat range and plugs gapped per CycleX instructions at 0.028. I am going to take them off again to check the jet size and floats. I will check the accel pump and check balls as well. Thanks for the tip.

 

[dirtdigger]

Take the floats out and throw them in a bucket of gas and see how they float. They should all float at about the same level and should float fairly even. Let them float for a while and see if they gradually start to sink. If they are dry it may take a little bit before they start to sink. Some times one side of the float will be fine but the other side will drop like a rock which of course will cause an incorrect float level.

 

[motogtp]

Take the floats out and throw them in a bucket of gas and see how they float. They should all float at about the same level and should float fairly even. Let them float for a while and see if they gradually start to sink. If they are dry it may take a little bit before they start to sink. Some times one side of the float will be fine but the other side will drop like a rock which of course will cause an incorrect float level.

You may be on to something DD. I wasn't sure what to check next. Carbs are clean, have 115 jets, pilot screws are out ~1 1/2 turns on all of them. Accelerator pump diaphragm looks good. Called Cycle X and gapped the plugs back to 0.024. Charging system is at 12.5V at 1200 rpm and 14.9 @ 4000 rpm although it seems to fluctuate a bit. It idles steady. Carb-to-engine boots have a few cracks but none that encroach into the band clamp area. It did seem like I had to rev it a bit more from a stop. If not the floats what's next? The needles? This is frustrating but I am learning a ton.

 

[motogtp]

I just saw a reference that says that 105 is the stock jet size for a Super Sport. Is that right? Are the 115's that I have now actually too big?