Originally Posted by Guidoracer
Even if it is a 27MHz radio, the bike does take all standard-sized gear, so you can replace it with stuff you might already have or better. Standard size servo, 540 motor, 1:10-size ESC, any size Rx...
Good to know. Thanks. I have a spare 40MHz receiver and micro antenna so I could put it on one of my stick radios - or I could use a FrSky 2.4GHz Rx with the Futaba FF6 and FrSky module I use for a couple of my planes.
Have you looked at the inrunners on GiantCod? There's a big variety of them, and they're mostly quite cheap. Anything the right length, or a bit shorter, should do. Brushless motors are so much more efficient, it doesn't have to be anything like the same size. The problem is picking one with about the right Kv, I guess:
I think I put a Black Mantis 2030 (4000Kv or so) in my Supatoys 1:5 scale bike, because it was just a bit shorter than the little motor that was in there, and quite a bit narrower. You'll want something a bit bigger for the M5 though.
I wasn't looking for a lot of power in the Supatoys bike, I just wanted it faster than stock because I couldn't get it to stay upright. Aligning the pinion with the first spur gear was the hard part - you can't see it on that bike, you just have to guess. I think I nearly had it right. I'm sure the motor was fine, I just didn't quite sort out the engineering. It took me a good half hour to strip it down each time I wanted to adjust something and I just lost patience in the end. Also, I was trying to use a smallish 3s lipo instead of the 5 cell NiCd brick battery, so the CG was probably too high for stability.