Youtube engine/tuning/bike people to watch:
2StrokeStuffing – awesome 2-stroke modifying adventures
The Workshop – how literally everything to do with engines and bikes works in insanely well explained detail
StuntexRu – ace russian stunt channel. some amazing riders on there, stunt championship highlights, training session, build stuff and more (as above)
Brian_636 – stunter from chicago, hood eats, stoppies for days
Dank Wheelie – from florida(?) wheelies all over the place
Jewsa – from Houston, TX. stuntlife real af
Motobroo – wheelies absolutely everywhere, great attitude
VW syncro forum – forum for VW’s syncro vehicles, mostly golfs but other syncro vehicles too
VPerformance – couple of bonnie scottish lads who run a youtube channel and website with lots of helpful info on DIY remapping. They seem to be mostly VAG-based.
Acosta Race Tuning – This guy builds some wicked scooters, FB tho, sorry..
Scootershack – awesome automatic scooter forum (mostly UK-based)
Steady Garage – some very cool and handy parts for custom scooter conversions. Superbly helpful too as I found out recently.
Pedparts.co.uk – spares and tuning parts for scooters
Adrenalin-Pedstop.co.uk – more fun bits for scooters and mopeds
Yamaha C3/Giggle/VOX fatty conversion – basically the only other person I’ve found doing fatty conversions on yamaha. Awesome build!
Misc useful tools:
Cylinder compression calculator (in german)