My Bike Tried To Kill Me Twice - Let's Find Out Why

In this video I'm disassembling my dirt bike to find out why my throttle remained stuck wide open twice. This is a mechanical failure that came suddenly out of nowhere and caught me completely off-guard. I fell pretty badly at around 50km/h and hurt my shoulder. I'm recovering pretty well and fortunately there will be no permanent consequences. The first time this happened I thought it was a case of whiskey throttle and my fault. Then it happened again a few weeks later and this time I was 100% certain the fault is not mine but mechanical on the bike. Of course I decided not to ride the bike again until this is resolved. Whenever issues like this related to throttle opening occur the inspection process must start with anything related to the throttle actuation system which includes the throttle grip, throttle cable, cable routing, carburetor and throttle slide. It's also a good idea to inspect the intake system and the reeds on a two stroke motorcycle. After inspecting everything at first I failed to find any signs of a mechanical failure. The throttle cable and slide moved very smoothly and I could never replicate the throttle sticking that occurred during riding. There were no signs of fraying on the cable nor anything alarming on the carb or intake itself. It was only when I took the throttle slide outside into better lighting that I found traces of mechanical wear on one edge of the slide. The culprit was ultimately the chrome coating that's present on the throttle slide of my two stroke Rieju MR300 dirt bike. Chrome coatings are common on carburetor throttle slides because they improve wear resistance and reduce friction, but in my case the coating began flaking, lifting and it seems that it eventually folded over leading to a stuck throttle slide. So what occured is that I tried to close the throttle but the throttle remained wide open instead leading to an explosive increase in acceleration that caught me off-guard and threw me off the bike. The danger with this problem is that it's unpredictable and it gives no warning signs before it actually happens since the clearance of the throttle slide bore is extremely tight. I decided to use some very fine grit sandpaper to sand away the worn and flaking chrome coating to prevent this from ever happening again. I decided not to buy a new throttle plate because I have no idea if this might happen again in case I get unlucky again and get one that's been poorly coated or whatever.