I don't think you can lengthen forks very easily. It will involve machining a new part. Either the top or bottom leg. most people adapt a set off of another bike. I just moved mine all the way down in the clamps. For the type of riding I plan to do, I figured stock fork with stock internals were close enough.
If you really have a 16 inch rear wheel, you are very limited in your choices. So far I have only found the trailwing. The other suggestions I got were either discontnued or not available in the U.S. The trailwing you need is the stock replacment tire for the Honda Nx250, if that helps. It is also a tube type tire. I am not sure if it is advisable to use this or not. I am hesitant to try it, until I hear from some other people.
A higher exhaust system would go a long way towards completing the look. But unless you plan to go through deep water, I don't know of any real advantage. I am keeping my low mufflers to make it easier on the passenger and easier to mount luggage.
timdog screwed with this post 12-23-2008 at 10:06 AM