need timing and carb help in OKC, OK area.

I am having troubles getting my bike timed and tuned. It was running really well just rich, until last night when it seemed to have lost 2 cylinders. This happened before, but it came back, and I assumed it was just fuel starvation. This morning It would not start and just coughed and burbled. I tried to clean, dress, and reset the points, and it never has been the same. I did put in 100 jets,(running stock airbox) 105's were in there before and it was really rich. It is a little better but less responsive on the low end, and little power on the top. I am at a loss, and was wondering if there were any locals that could help a brotha out.

year and model and any mods done will go a long way in helping to diagnose.....

oh sorry forgot that. 78 kz650b stock as of now, even airbox. old pipes though. I just worked on the timing some more and got something decent out of it. I am wondering if I have an undervolting issue that is dropping one set of cylinders.

i m not well versed in 650-750 stuff, but it sounds like an electrical problem....on the big bikes 1/3 and 2/4 are on seperate coils..pull your plugs and see whats what...could be a bad coil...could be low voltage to both...bad battery..carbs clean?...valve adj done fairly recently?
a lot of variables......good luck....

its the same on the small fours 1/4 and 2/3 fire together. I finally got a decent tune on it, I am now worried that I have run too lean. I went from 105's to 100's on jet size. The 105s were running pretty rich, and would sometimes plume black smoke. I just happened to have 100's so I threw those in, a little air fuel screw adjustment, and now its better, not best but better. I also think I may have fouled a plug. I am going to look at repowering the coils, and I ordered a dyna s ignition.

valve timing is probably needed, i just don't have the green, and it doesn't seem that far out just yet.

ndeli55 wrote:

its the same on the small fours 1/4 and 2/3 fire together. I finally got a decent tune on it, I am now worried that I have run too lean. I went from 105's to 100's on jet size. The 105s were running pretty rich, and would sometimes plume black smoke. I just happened to have 100's so I threw those in, a little air fuel screw adjustment, and now its better, not best but better. I also think I may have fouled a plug. I am going to look at repowering the coils, and I ordered a dyna s ignition.

dyna s is a good place to start...rules out the points and its set it and forget it....i would still check battery voltage after sitting overnite...anything less than 12v putting a multimeter on dc volts and putting red on pos and blk on neg is a weak battery, which will screw up the whole works.....you are cutting fuel down and are still fouling a plug....i am far from an ase tech ,but you might have an low voltage problem......good luck and let us know how ya make out......

tested the power to the coils, and it was merely 10.84v. Terrible. I also checked the battery and was looking good at 13+v. I am in the process of doing the wired george coil repowering mod, and I think I have tracked down at least one problem.

its amazing what a new ignition system will do. I repowered the coils, and installed a dyna s. I was running dark black and sooty plugs before,now with the same set up my plugs are completely white.

I think its the right direction, I have 102.5s to through in there tomorrow.