cdis,
i have had this same problem. you have two options. get a tekno kit or make/buy a spacer. i made my own by using CA to glue to pices of 3mm carbon together. it was just the right thickness. here are some pics. if you have 1/4" carbon or alum laying around just use that. drill your screw/shaft holes, and then cut the piece the same diameter as your motor can and grind down one side so it looks like a 3/4 moon. then countersink the two holes that wont be used to mount the motor. this way you can use a flat head screw to hold the piece to the motor and the the other 2 holes to mount up. depending on your mesh you might only be able to use one screw to hold the piece to your motor. in these pics i have two but i ended up having to use only one screw with a 13t pinion. good luck. and yes RCM sells something almost identical out of alum for like $12 i think. you will have to search the site though. its not the black alum Neu endbell cover but its a silver alum 1/4" thick oblong shaped thing.
oh, and one other thing. you will most likely need a Tekno long shank pinion to reach the spur now. thats what i had to do. because the motor now sits further back from the spur a regular pinion wont reach. have fun!
