Well, I took another look at the drivetrain last night, after a proper off-road race meeting. As I mentioned above I chipped some teeth from running the mesh too loose at the meeting.
Gave the gears a good tidy up, scraped out the tooth chippings, spent a little time with some finer shims, and got everything running as smooth as I could but with no backlash.
Funnily enough the shimming is getting closer now to the original kit setting. I have the front gearbox midway between the kit and alternative settings, I have the rear gearbox at equivalent to the alternative setting.
So I think I was a bit premature in my disappointment with the drivetrain (sorry Yokomo!). Give the car a few solid race meetings, keep and eye on the drivetrain, don't run it loose, and it should bed in nicely.
I was probably a bit rash in modding the top deck and centre gearbox top too. Thankfully the spur is undamaged but I'm not sure the mods were necessary at the end of the day - nobody else seems to have done them! (Note to self - must avoid late-night wrenching - tired mind + obsessive nature = silly modifications)
