1979 Honda CB750K Exhaust Change.... Carb Re-jet question

[BGalvin]

Apologize if this has been asked, but I can't find it....

Stock 1979 CB750K.

Bike sat for about 8 years.  
Took to a good mechanic and:
 -Carbs cleaned and all gaskets replaced.
 -Front and rear tires
 -New voltage regularot/rectifier
 - stock muflers replaced with MAC 4 into 2 mufflers

Mechanic says the bike is now running lean and he can't get come out anymore on the adjustment.

Talk of rejetting now.   He says that this is trial and error so it may take a few times to get it right.

I already have almost $1500 into the bike......   Can't go much more.

Anyone done this before?   Did you change the jets?

Stock jetting is 68/102 for the main and 35 for slow.

What jetting should we change and what do we change it to?   Can we just go up one size to a 105 for the main?

Any help is appreciated.

Bill

[Johnnylevi]

you do not need to rejet for a mac exhaust... I run 105 mains in my bike seems to work well.

[TOOLS1]

Exhaust changes do not usually require re-jetting. Has any changes been made to the air box?
TOOLS