Finally found the time to test ride the rack mount this evening.
The brand new engine (Thanks to Jim Wilson at Pedalchoppers!) fired right up and off we went for a nice half hour test ride around the neighborhood. My initial impression is that this is one of the nicest chine girl powered bicycles I have ever ridden. Even though the bike itself is rather cheap and flimsy, with the motor pushing you along, it rides like a Cadillac! All the motor and intake noise you hear in a frame mount bike is behind you and inaudible. All you hear is the exhaust tone. No ringing, gear whine or tinny side cover noise at all. I'm very pleased with the first ride and am looking forward to playing with my newest toy! This is turning out better than I had hoped.
It was problem free with nothing flapping or bending. No grinding noises or ugliness to sully my very first miles. I did get some chain stretch from the cheap stock chain so I will have to redo the mount or install some kind of tensioner to get the chain right.
I'm considering a roller guide like this.
Also have a very small issue with the seat frame tapping the pipe a bit at full travel, but this will be very easy to fix by simply jacking the frame up a touch by moving the shock mounting point. Instant clearance and a slightly stiffer spring rate for ten minutes work. (This easy fix is why I was downplaying the problem to those of you who warned of interference)
Trying out the roller setup tomorrow. If it doesn't work as well as I want, I'll start working on a fully adjustable pivoting mount like the final version I've been seeing in my minds eye. This ugly hack job of scrap and bits is just a first draft.
Please believe I do nicer work than this rough prototype. This was built by me holding stuff in place and blind tacking it together, stepping back and eyeballing it, bending to suit, then welding on bits of handy scrap until it wouldn't move anymore. I have a very organic process when trying to create order out of the chaos that is my usual work area. My prototypes tend to be very ugly and disorderly looking, yet very strong for the purpose needed. I'm real good and making whatever is at hand work. Making it pretty and sleek is something that takes me lots of experimentation.
On a side note....
This shorty tuned pipe is one of the best sounding setups I've had. Very mellow and powerful sounding with a dirtbike rap and no tinny weedeater noises. I think it's from the large silencer diameter and straight through construction. It is very heavy however and I still need to add a second mounting bracket for the pipe to help carry the loads. Need to settle on final engine placement first and figure out a chain adjustment system.
The engine is brand new so I cannot tell if this sweet sounding pipe will help power yet, but the engine does feel very snappy and responsive even with less than 10 miles on it.
I have seen this before with my builds. The (stock) chinagirl likes a pipe with a very short run better than long rear exit setups.