I had two corners break on stock reeds and it would idle fine, but would instantly bog with any throttle. I thought it was a clogged main jet, and I overlooked reeds. I reached down there and felt them to make sure they were still there and for some reason thought that was a good enough investigation. It took awhile to pull them out and find the problem. I have had many experienced riders say similar things about reeds not mattering. Some bikes don't even have them. The same thing with powervalves. I could have saved money on my rebuild on the k5, when my engine builder offered to weld it closed. He said it would work fine without it for hillclimbing. I admit to not being an expert. Most of the guys on here know more than me by far about 2 stroke performance. I am just adding to the conversation about my personal experience. When I explained what the problems and symptoms were and the cure, I had some wrinkled eyebrows for sure. Only thing that I can figure out, is that if its not broke don't fix it. If it is broke, fix the obvious first. It is always tricky to figure out causes of performance issues. I just tell everyone how the thing is acting and somehow I always start hearing a common idea that makes sense to check. It is usually visually obvious, once I get to it. Also it was brought up on here that the little guys in Japan figured out alot of the engineering already. You don't have to stray away from stock to get a good running bike. At least start with a solid stock bike, and trim and tweak to set it up for personal preference. My point is, the k5 is awesome, but they are all used at this point. With mine completely redone, I cannot afford to sell it. If you get a good deal on one, it is going to need work and $$$$$$$. If you band-aid it up just to get it running, its fun, but you do not get the full experience. The best thing you can do for it, is go over it with a fine tooth comb. Get it all solid and it will not do you wrong, but plan on keeping it.