bs38 on kz750 popping question

[section8joe]

I know this isn't the correct forum but I'm having a bit of trouble with my buddy's kz. I have the carb's synched, valves, timing and cam chain are ok but the left cylinder keeps popping. Could it be the floats too low on that side? Hole in diaphragm? One thing I forgot to add. I assume this is caused my by a lean mixture on that left side but when I adjust the mixture screw the popping slows down when I turn the screw in(leaning it out). The bike also pops less when it's warmed up. Carb's were just cleaned and all passages seem ok. I know it's not an xs but any ideas?

 

[xs650newb]

Hopefully someone with more knowledge can confirm this:
If it pops less when it warms up it would indicate you are too rich because the bike should lean out as it warms up.

Also, this goes along with the fact that is pops less when you turn the screw out.

Best,
Adam

 

[retiredgentleman]

I know this isn't the correct forum but I'm having a bit of trouble with my buddy's kz. I have the carb's synched, valves, timing and cam chain are ok but the left cylinder keeps popping. Could it be the floats too low on that side? Hole in diaphragm? One thing I forgot to add. I assume this is caused my by a lean mixture on that left side but when I adjust the mixture screw the popping slows down when I turn the screw in(leaning it out). The bike also pops less when it's warmed up. Carb's were just cleaned and all passages seem ok. I know it's not an xs but any ideas?

I sense that you did not remove and clean the pilot jet..............very tiny orifice that must be totally clear. Check the float level as well while the carbs are on the bench.

 

[section8joe]

I did remove and clean the pilot. I also set the float levels. Still popping. It's weird though, as I lean out the mixture screw the popping slows. The bike is also running on one cylinder until I give it gas. Then it runs on both. I'm gonna try to put brand new pilots in tomorrow and see what happens.
I tried to test the coil and I was getting zero resistance on the primary side and also on the secondary side. I'm not sure what I'm doing wrong but I think I'm not using my meter right. I tested a known working coil and the primary side tests ok but the secondary side reads something like 27.56k. hmm I don't know.
I also ran the bike and took off one spark plug at a time. The left side kept running with or without the plug and the right side always made the bike stall. I'm thinking the left cylinder is NOT getting enough gas. Hopefully the new jets will fix my problem. Is there anything else I can test or try?

 

[5twins]

Carbs may just be out of sync. You also need the clean the pilot passageways, the paths the fuel from the pilot jet travels through. A clean jet does no good if the passageways leading into the main bore are plugged.

 

[hmusket]

Have you tried the KZrider.com forum? There is a whole section devoted to carbs.