The Delrin slider is a maintenance item on most dirt bikes, including the big mfgr Japanese models.
I have had chain adjustment mechanisms that took 5 different tools and at least 20 minutes to make an adjustment.
On my last SV-650, when they added the ABS, they broke the procedure to replace the rear brake pads. It went from the usual 5min & 1 tool, to spending an hour having completely to disassemble the caliper attachment bracket system.
Also, the ABS hydraulic unit blocked the cam tensioner on the rear cylinder, so you then had to drop the entire rear swingarm to get to it and adjust the valves.
Several models of SV-650 cam chain tensioner mechanism designs had a habit of relaxing and letting the cam chain loosen and lunch the engine. They went through at least FIVE different designs that I'm aware of. C'mon, cam chain tensioners have been around for 40 years, is it THAT hard?
The rear brake caliper bracket bolt on my FJR-1300 seized, tearing a big chunk out of it and necessitating a new rear caliper. Dat wuz some bux.
On a lot of Yamaha sportbikes, including the R1 and my FJR-1300, you have to drain the coolant to even check the valves, as the coolant lines run through the middle of the valve cover, so you have to disconnect them to remove the cover.
The OBD on my '90s era Camaro was completely proprietary. No 3rd party shop could work on it. Same for the ABS system. This is the car that tried to kill me when the ABS failed.
Back in the '80s, with drum brakes, it was a common thing for the rear brake torque arm to fail, allowing the rear brake to not only fail to do anything, but lunch the brake, the rear wheel, and the swingarm. The attitude was "oh darn, hate it when that happens. check your torque arm bolts regularly"
Ask the BMW rider forums about the many common BMW faults, including complete rear swingarm failures, that BMW refuses to acknowledge.
To be honest, it's HARD to design a motorcycle. Modern ICE bikes are so good because they've iterated the living fuck out of the design and learned what not to do, as well as what to do. I was there in the '80s when the Interceptors and Ninjas, and other bikes showed up with brand new features like anti-dive, deltabox frames, and disc brakes on both ends. The 500 Interceptors used to fire rods through the blocks with depressing regularity. Everyone disconnected the anti-dive systems because they turned the brakes to complete mush and were impossible to completely bleed. See any bikes with anti-dive these days?
The joke about first adopters that "you can tell the pioneers by the arrows in their backs" is sadly based in fact.
True that. I've had a worn chain snap on an ER-5 which then proceeded to then wrap itself around my rear wheel.
What's even more fun and expensive is when the chain wraps around the output sprocket and proceeds to destroy the engine case. I've see that happen a couple of times.