Motorcycle Repair: 1985 xj700 maxim x, vacuum leaks, vacuum leak

Question
I recently had a mechanic repair my bike after it set in my garage for 12 years unstarted. He did the carbs,spark plugs,new plug caps, cleaned gas tank-very minute trace of rust in tank, changed oil and filter. My problem-in 1st gear from dead stop it does not pickup with good power-sluggish. anything below 3500 rpm is sluggish. Above 3500 rpm, any gear runs like a jet. It usually has to be choked heavy on start- up until warms up thoroughly before idle smoothly.  

Answer
Hi Ron.
Check all your connections for the manifolds (Manifolds to carbs and manifolds to heads).  Make sure that there are no air leaks.  Then check the manifolds themselves for cracks and the like.  You could have a small vacuum leak because of things like that.  If the manifolds are cracked, then replace them.  There is no repair for a cracked manifold other than complete revulcanization of the part.  Also check the connection of the carbs to the airbox assembly.

The way to check for vacuum leaks in the manifolds is to spray a little ether (automotive starter fluid) at the suspected areas of the manifolds while the engine is idling.  If the rpms increase when you spray the area, then there is a vacuum leak there.

Start with that and see what you find.

Good luck and ride safe.
FALCON