So I just came across a Yamaha U5 Newport in pretty decent shape aside from a massive spray bomb job. I know it is pedal deficient, but it is a solid 2 stroke oil injected three speed setup. I'm willing to take some shit about it being a scooter/motorcycle if I can get some answers from the generous hive mind.
I have been searching for a while and I really, really can't find any solid information on these. I'm hoping the big brains here have some kind of experience.
It starts (both kick start and electric) and runs well, no issues at all so far. It gets up to 40 on the flat if there is no wind. The oil injection setup seems to be working and really looks like it's in great shape, so I'm sticking with it for now.
What I'm really wondering is if the top end is compatible with the QT50 or other Yamaha kits, or if someone has an idea what I can do for a little more performance. Carb/pipe are an obvious choice, but the cylinder has a weird threaded connection, not a bolt on like the QT. I would like to avoid hacking the header unless there is no good option otherwise. For a chamber, I would want something with massive bottom end as this motor is never going to wind out.
The carb is under a side cover and I think it's case inducted. I have not really pulled it apart to check yet.
Any one mess with one of these and have some tips? Anyone have a link to a shop manual that is not a shitty $15 xerox from Ebay?