Spawn of Satan

[will e.]

My bike started running like crap on my way to work the other day. Mid throttle was mostly fine but my idle was pokey and frequently would stall out. After some digging around in the carbs I found that the diaphragm in SOS was warped. I decided to bypass it as I had done once before. Since then I've been having some issues similar to what I experienced previously when I had bypassed the SOS. Occasionally at idle the bike will suddenly die. Sprayed a little wd-40 to test for a compression leak on the carbs and carb boots and everything tested out fine.

 Has anybody else experienced similar issues?

Will

[will e.]

In case anyone is interested this is what I did.

I was having a hard time finding a replacement for the warped diaphragm so I decided to do a little digging. Looking through exploded diagrams from similar model years I found that later CB models have a similar diaphragm built into the side of the petcock. On a lark I ordered a petcock from a early 90's Nighthawk. The petcock itself didn't fit my tank, an 81 C, but I suspect that it might fit my other tank which is a K, haven't had a chance to try it out yet. I monkeyed around a little and found that I could take the whole diaphragm assembly off of the petcock and 'marry' it with my spawn of satan. The rubber itself is shaped a little differently, it doesn't restrict gasoline flow to the main gas line leading into the carbs but does restrict it to the smaller line leading directly into carb #2. I'm assuming that this smaller secondary line only sucks gasoline when needed(?) preventing the bike from stalling at idle, or during hard acceleration. Just took her for a test ride and she's running beautifully.  

[TOOLS1]

That smaller second line is the vacuum lines that controls the SOS. When the engine starts, it creates vacuum, and that vacuum coming through the line is what opens the valve. This is often problematic, hence "spawn of Satan."
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