Motorcycle Repair: 82 Maxim 750 - dead spot., auto repair shop, little consequence

Question
Hey Chris, Thanks in advance for any info you can shed on this problem It's driving me nuts. I am a mechanic who worked for a few years in a yamaha\ auto repair shop. I've done mostly auto stuff though but did a lot of carb cleans but not a lot of final adjusts.Here it goes I boght the bike with carbs supposedly cleaned the year before but not synched. I synched them with my mercury gauges and then it would climb off an idle by itself to about 4000rpm and sit there, discovered the maxims need a special tool to block off yics system to synch properly, built tool off plan found at www.motorcyclecarbs.com . resynched carbs. Still the same but discovered if you back the idle screw off till it will no longer idle that the problem goes away. Pulled the carbs blew and checked everything including making sure all passages in idle circuits were clear as per diagram in manual.Put carbs on found air leak at end of one throttle plate shaft, fixed leak. Set float levels low and then right on. I then tried to set the idle mixture screws as per instuctions at previously mentioned site. In till idle drops and then out till drops and then in between. Fine going in but then you can back them all the way out with little consequence.After all this the idle is now pretty good but when i try to accelerate there is one heck of a flat spot and stumble that make it impossible to ride.Once past that flat spot it seems to go pretty good..
    The bike is stock except a four into one exhaust.  Sorry for the length and I'm sure i missed a few ythings I've done and tried butI am pulling my hair out.  

Answer
Hi Daniel.
 You built the YICS shutoff tool?  Pretty good feat.  My only concern with that, and it could relate to the problem, is that if any of the measurements were off by so much as a micron, then that could throw off everything that you did in the synchro portion of this fix.  Even the o-rings on it need to be precise.  If it is even a little off, then it can prevent the carbs from beig synchronized properly.  Check the carbs with the tool off the bike as well as on and I'll bet that you will see that the carbs are a bit off, and that is where your flat spot is from.

 I was looking at that tool for my 83 XJ900RK, which also requires the tool.  The thing that kept me from getting it was the cost.  It's a $97 dollar tool (as of 3 years ago), that I don't believe that they even use anymore, except on the Maxim and bikes with the older Maxim (any XJ series) engines.

That is about the only thing that I can think of, unless the carbs need to be cleaned again or are so bad that they need to be replaced.

Good luck.
FALCON