CB450 Miss after 7,000

TripleKing

Been Around the Block
I have the timing set and the carburetors synched on my 1970 CB450. She pulls hard through 7,000 RPM, but at about 7,200 she begins to break up. It goes away after about 7,500, especially if I open the throttle all the way. I recently installed a 190 jest in the Mikuni 32s. I had a 185, but that seemed a but lean at high RPMs. The bike has 60mm pods and stock exhausts but a previous owner removed the baffles.

it is also having another issue. I warm he bike up and set the idle, but after riding for awhile, the idle will get real low and even stall unless I blip the throttle. When I do that, the engine will hang at 3,000. It will then go back to stall speed. I went over the slides thoroughly and they are not sticking. I checked for leaks by spraying carburetor cleaner around the boots and I can find no leaks. I am a bit stumped.

Edit: Just checked by plugs and the left are on the dark side of normal, but the right is definitely rich. I also notice that when the throttle is first blipped, a little black smoke comes out of the right exhaust. It is definitely not blue.
 
Sweet. Was about to say that before I saw your reply.

I had the exact same issue and it was because my needle was running too rich. Raise the clip, lean it out, problem gone :)
 
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