I've got an odd thing happening on my '74 cb740K. When I'm riding around 50-60km/h, throttle around the 1/4 position, the bike sounds and feels like it's gurgling. Almost as if it was on the verge of running out of fuel. I've had an awful time trying to sort it out.
Backing up:
Over the summer I rebuilt the top end of the engine - new pistons, rings, valve guides, etc. I never had this problem before the rebuild that I can remember. After the rebuild, the engine runs much better and has more power, but I've got a weird gurgle.
I'm running the stock airbox. I used to use a K&N air filter, but put an OEM one in after the rebuild after being advised the K&N would cause it to run too lean. I haven't tried swapping back.
The bike idles perfect and pulls hard through all the gears. At highway speeds, it feels and sounds perfect. I'm told it gives of a pretty gassy smell if you ride behind me though... Maybe I'm running too rich? I played around with the air mixture screws but it didn't help.
I've gone through the carbs and rebuilt them again. They have new jets and gaskets, all passage ways are crystal clear. I'm using the stock points ignition and checked the timing. It's dead on at idle, but at 3K I can't get the marks to line up perfectly. I used to use a Dyna-S system and had the gurgle then as well. The Dyna died on me so I swapped back to points. Also checked valves and cam chain tension.
Any ideas? If I smell gassy and gurgle at lower-mid throttle, perhaps I should drop the needle down a notch?
