'79 KZ650C Misses/Backfires (cont.)

I've cleaned the(Mikuni)carbs and have run into another issue. On the rim of the bowl inside, there is a clip holding a ball bearing and a round brass piece. What purpose does this have ? I'm asking because I found that one carb was missing the clip and bearing. Patton had made me aware of petcock difference with the vacuum hose disconnected at the #1 intake and plugged:

BTW, the petcock seems to be a vacuum type(on,res,pri). I now have to figure out why and what else has been plugged. Could this cause or be part of my original problem ? The carbs did not seem to be that dirty.

I was hoping to get some answers here. I am not sure I'm ready to replace the carbs. back on the bike. The previous owner had disconnected the vacuum @ #1 intake and plugged but did not change petcock and vac line still connected to #4. Should I try and restore to original setup?

can you please put a picture of what your talking about or even a parts schematic up it may or may not be needed.

I'm sorry ! I have been trying to copy and paste diagrams and images to this reply and obviously don't know how.

kzrider.com/index.php?option=com_kunena&...d=3&id=289519#290487

I copied a link here, if that helps. Notice smaller hoses teeing off #1 & #4 to center hose going to front of engine.

The link you provided is for the smog system. Most guys remove and throw it away, especially when it stops working. On the front valve cover just run a hose (3/4"?) from side to side. Plug off the vacuum nipples and your set.

Here is what your talking about? It's part of the the pump circuit on "pumper" carbs. Lean jetting required an accelerator pump system. This was the one way check valve.



Here is a vacuum diagram (Thanks Patton) for you showing what you need to know?

Thanks Bluemeanie ! Now, do I need another type petcock ? What had me baffled about this is the PO only capped off one small vac line on #1 intake and everything else was normal. My plugs indicate a rich mixture now - black and smutty dry.

If your carbs have the nipple for the vacuum petcock you can just run that. It's nice not having to remember to turn off the gas. You can if you want, cap off that nipple and run a regular petcock. As far as your sooty plugs go you really need to check out WG's coil mod . Most people here have done it with great results. About an hours time and maybe $20 will make a big differance. It can in many cases eliminate sooty plugs. Good read, easy fix.

Thanks, I'll just cap off everything but the petcock line and use it for now ... I've developed another problem trying to fix another. Now it's not firing.?. The last thing I checked and set was points. Using a feeler gauge and ohm meter, I thought I had it. The battery was too weak (or so I thought again) to crank and check timing with a light so I charged overnight and this morning started over. I cranked and it ran on choke for about 5 sec. a few times. When it died, it was instant. What in the world could I have done just adjusting points to have caused this problem. I've checked wiring for opens and shorts, also tested coils ( 3 ohms pri., 23 sec.)

I am lost for next moves. Out of frustration, I pulled the condenser off and according to test, they fail- no arc. I don't know if that would cause it to not fire. I even swapped the primary wires on the coils and it made no difference in the firing ...2&3 points arc but not 1&4. Any suggestions ?

Someone else is going to have to help you here, I'm not an electrical guy. But...... If you have about $125 floating around you should get a Dyna "S" electronic ignition. Best thing I EVER did! Bike fires up so fast and of course it's a set it and forget it.

Thanks anyway, Bluemeanie, this bike belongs to my brother(who is even less of a mechanic than I) and I'll let him in on this latest misadventure. Hope he goes for the Dyna "S". If not , I still need guidance.