Cheers Sam, haven't played around with different sized axe sprockets yet. It did cross my mind when I first converted to the scooter motor but at the moment I'm happy with how it's running so will leave it for now. And yeah, the motor's currently got a 9-tooth sprocket on it which is the lowest I could go before running out of boss material!

Update

The battle for weight loss has been won! After drilling 140-odd holes, I managed to get Onyx down to 13.6kg:



The only problem is that my scales are only to one decimal place, so it could be anywhere between 13.61kg or 13.69kg. I thought about drilling more holes to be sure but then I realised that:

- I'll lose a bit of weight when I swap from Victors to TZ85s (might even put the XL from Carcinus back into Onyx as it'll be lighter)
- I can ditch the RX battery, mount and switch and use the BEC on the XL or TZ85 controlling the weapon
- I estimate the tether to weigh around 50-100g, and tethers aren't included in the weight (will actually weigh it to be sure)

So the combination of those three things should put it safely underweight; I'm also hoping there will be enough spare to afford some protection to the currently-quite-exposed scooter motor, but we'll see.

Also, it you ever wondered what 375g of HDPE swarf looks like, here you go: