I am so glad to see this thread. Last year I did a quick fix-up on a QT and rode it for like a month before selling it. I liked it so much better than the Honda Express models, that I picked a couple up for a decent price last month for a winter project, and to have one to bomb around on for keeps. I'm not new to bikes, and some of you may have seen my work on other boards, so I'll give up some ideas I have for these little peds.
I've already popped off the rear rack for restoration/cleanup, and I've pulled the carb for inspection. The tank shows some surface rust, and this was evidenced by the fine rust powder I found in the bowl. It's jetted with a 70. We'll see how well the carb cleans up. I'd like to replace the stock airbox with something a little K&N, since I never really liked the side covers. I definitely want to do the 60cc thing. BTW, what kind of compression am I looking for on these engines? Anyone? I'm reading 90 and wondering if that's high enough, but couldn't find it in the shop manual.
I'm also looking to do a lot of 6v LED replacement of lights, especially the turn signals, so I'll end up replacing the flasher relay with a low threshold job. I've also found some interesting tires that I'm wondering if anyone has fooled with. They are IRC NR-77's. The QT50 stock sizes are 2.00-14(F) & 2.25-14 (R). The IRC's come in 2.25-14, which is listed as a front tire, and 2.50-14, which is listed as a rear tire. I was thinkin' a pair of fronts would do the trick for both front and rear, and they have a much better rubber compound, as well as a more modern tread.
So, there you are. Any advice would always be helpful, and I'll keep you all posted on the progress.