I have a Baker DD6 installed and every once in a while, regardless of speed or gear, I cannot shift (up or down) gears because the shifter feels like it is locked. It is completely random because before and after the lock up, everything is very smooth.

 

Check the shift linkage first, make sure it is free and not binding. Also make sure the linkage rod that goes between the foot control and the transmission shift lever is parallel to the motorcycle. If it is on an angle it can cause binding. Next check the shift lever on the trans itself and make sure it is tight and not flopping around. If all this checks out, it may be time for us to have a look at it. Random shift problems are usually linkage,