Originally Posted by simple

There's more than one way to get an 85mm rollout - have your tried all combinations of pinion/spur/wheel diameter No just 72/45 with 43mm rear tires. I did try a 47T and 49T pintions which gave me more overall speed but still well behind everyone else.- they have an effect too. There's also physical timing on the motor. What is it at now? 51 Degrees on the endbell.
All have an effect on the output of your motor, and sometimes the slightest change can have a noticeable result. Sorry for the confusion, but its a learning experience. It sure is!
There are several variables to getting it in the sweet spot, and you've only mentioned a few in the overall equation.
I don't think, as far as I can tell from the short paragraph of your description - that there is anything wrong with "the motor". Interesting thanks. This little pancar (ASMX A12) has been quite the adventure!