Seems low to me, spec is IIRC around 150psi, but check again when hot as it may make the difference. My M900 with high-comp pistons, when tested hot gives 213psi front, 208psi rear but cold it's 20psi down on the front and almost 30psi down on the rear...
What's the miles on the engine? As I said before, I had the same problem and it sorted by leaning up the carb. Have you noticed the oil level drop in the glass?
My SS compressions when hot are about 160 - 165..........did cold try for the hell of it..............they happened to be 145.........
I'll report back next week on my next days off. I put lucas oil leak sealer stuff in it today to see if that helps. Al think the 750 has higher compression
So I got some Lucas engine oil stop leak, put it in and went for a run then checked compression yet again. Engine got and this time I twisted throttle ( suggestion from this forum) which helped and guess what, it have me 150psi on rear and 160 on front. Attached is a pic of the plugs too.
150/160 is more like it, throttle wide open, engine hot and no plug in the other cylinder is the way. As for the plugs, I'd be checking the carbs...
For starters, I say turn the pilot screw in one turn on the sooty cylinder (don't expect pilot screws to be set the same -- float level can affect them) but also check the main needle is on the same notch (You would be surprised how many people can't get the clip in the same place on each needle)....
