Allen Wrench, I once had a fuel valve that I could not take apart to see why the flow through it was bad. I eventually ran enough gas through it and moved the valve open a shut a number of times and then it got I guess some gunk out. The I hooked it back up to the carb I clean all out and was fine. I may still change the valve one day if need be.
As for kids needing bigger bike, I did partially that. I'm a big kid
Just for laughs I adapted a 24 inch wheel bike for a Burner bike for one of the times in the past attending Burning Man Event. The seat post I got was high enough for my legs, but then I had to lean to far forward and down to reach the handle bars. I eventually welded even smaller handle bars from a really small kids bike on top of the existing handle bars. Four hand grips take your choice.
See "Art Fish Mobile Motor Bike prior Motor Bike DIY'er build to add side car maybe?"
Page 14, posts 138, 139, & 140
I've yet to take the motor bike built now using for off road riding and make it an event bike. I have the thing started, but need time to get to it and so later. No ticket this year to the Burning Man Event, but have looked at some pictures of some really good sculptures and mutant vehicles.