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81 Cb750C running and driving good but popping and backfiring

Skoobydooo

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I’ve been trying very hard to figure out what’s wrong and I’m stumped btw I barely have access to special tools or money for new parts. So my bike is popping and back firing out of right exhaust, I’ve tested my coils with a multimeter they’re good, never had problems with charging I’m pretty sure the the stator and stuff is ok I just replaced the battery, it could probably use new plugs bc even tho they’re new they’re carbon fouled. I know my carbs are good and clean and decently adjusted (as far as pilot screws) so it drives pretty normal just kind of popping and’s back firing under acceleration but it idles smooth
 
Something cheap to check or just replace to drop from the equation is spark plug caps and wires. Those NGK resistor caps are good stuff, but if old they have 6 electrical connections inside that can corrode and even work intermittently. Very similar issues as when a coil is going bad.
 
Something cheap to check or just replace to drop from the equation is spark plug caps and wires. Those NGK resistor caps are good stuff, but if old they have 6 electrical connections inside that can corrode and even work intermittently.
That’s good info I didn’t know there was that many connections for the plugs, my bike spent most of its life inside but I still wanna try to replace anything that has to do with ignition but I don’t know exactly what all I should replace (being that everything used to work fine until now) also does anyone know if I put new float needles in do they need to be adjusted and how
 
If you have plastic floats there are no adjustments but the float height should still be checked to whatever manual. Check the needles length to the originals length, some aftermarket float needles are not correct, float height will show that too. Polish the seats with a Qtip or pointed wood dowel with a little Brasso or chrome polish.

With the plastic floats my float height always comes out about 1mm too high, low as you measure them upside down, but they're always the same as each other.
 
If you have plastic floats there are no adjustments but the float height should still be checked to whatever manual. Check the needles length to the originals length, some aftermarket float needles are not correct, float height will show that too. Polish the seats with a Qtip or pointed wood dowel with a little Brasso or chrome polish.

With the plastic floats my float height always comes out about 1mm too high, low as you measure them upside down, but they're always the same as each other.
Ok I didn’t think there was much adjustment but I read something that made me think maybe somehow but anyways update the bike is running better I drove it around and it drives pretty much normal but it’s constantly popping
 
Did you check the ACV (air cutoff valve) on the carbs? They are meant to prevent decel popping by adding a bit of fuel at decel. But if the diaphragms are torn, have holes or tears, they don't work.
Outside of carbs, if an exhaust pipe isn't tightened against the head, the fresh air will give you pops.
 
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