Suzuki 2 Strokes

OK....So She is runnin' OK, but seemed a bit weak today, so when I got home, I pulled the plugs for a sandblasting. Left & center looked pretty good. The right was a bit gobbed up (not bad) with some kind of light-ish granular deposits. Don't know what theat means, but worth noting I guess. I checked compression also. 105--120--120. I'm not real sure about the 105 'cause the fitting didn't seem to thread into the plug-hole as far as the other two did, so it might not have sealed as well. I also put the vacuum gauges on the carbs just to see if they were close to balance. I am surprised to see practically no vacuum on any of them! Maybe 1 inch (1 graticule) on the guages. I checked 5 different guages for consistancy & they all indicated the same. When I rev the engine to about 3500 rpm, the guages go up to about 5 inches, then back off to idle (about 1300 rpm), they settle back down to about 1 inch each, without much bouncing around. They were all pretty much the same, so I didn't adjust anything. The intake boots are less than 4 yrs old & are not cracked. I've never vacuum checked a 2-stroker, so I don't really know what to expect. The guages show 18--22 inches as the "normal" range. She's still running pretty well!
Any thoughts?

Did you do the compression test with the engine still hot, and take the readings after 8 to 10 kicks on the starter in quick succession with the throttle held wide open? I'd try and take the readings again to get an accurate test on the left cylinder, that is a little low at 105psi compared with the other jugs.

Just my 10 cents, but I've heard it's not worth using vacuum gauges on 2-strokes because of the reflections and resonances in the inlet tracts. Anyone else got a view on this?

Craig380 (et al),
After doing a bit of research regarding the "vacuum" measurements, Craig380 is correct that the vacuum is not a reliable indicator for 2-stroke engines. The prescribed method to balance the carbs is (basically) to remove the plug from one cylinder at a time & tweek the idle screw for the other two. Then repeat in all combinations of plugs & adjustments until all pairs of cylinders result in the same idle speed. (Over simplified description!)

I have not done so yet, but will do it soon, just 'cause I haven't & would like to know if they're balanced.

As for the low compression; I suspect the gauge fitting was not fully seated (as stated in my 1st post), & besides, I'm not really concerned about it at this point.

Thanks for your reply(s). Would welcome any other comments on the subject.

The gray and granular residue is usually from detonation, and that is aluminum blown off the piston. I would check the timing, and also for air leaks. This could be a major problem.