15 mile report on Hua Sheng kit build

Local time
12:55 PM
Jul 15, 2008
Here's my report on my Hua Sheng 49cc 4-stroke kit build. It has a Hoot gearbox that has beveled gears, so I'm apparently one step up from some of the problems listed in older threads on this forum.

First, I must say that while there have been some trials and tribulations, I created a moving vehicle with no more trouble than I expected, given that I was starting with a used mountain bike and a box of parts that was loaded who knows where in China. It isn't a new BMW and I've only got about 15 miles on it, but it's certainly not the horror show implied by Bikeuser in the thread "4-strokers are garbage!!." I'm guessing that he has an HS engine as well given his description.

Performance-wise, I've only had it up to about 21 mph on the flats (still breaking it in) but there's plenty of room left on the throttle, and it will pull me up a 10% grade (Seattle has hills and I live on one) at 15 mph with mild pedaling.
The engine is is louder than I had hoped, but I think I can fix that with a better muffler. I know, I know, loud pipes save lives, but I want my hearing too.

Also, the transmission has a high-end whine in it that turns into a high-frequency shriek, and seems to go away (or be drowned out by the motor) after about 15 mph. Might be the gears, and I've been having fun playing with gear oil per Cruiser66's posts, or it might also be something in the chain system. The idler roller is a total piece of doo-doo, wish I could say that in Chinese, and I might try making a roller out of a rollerblade wheel or something.

Much of the 'minor' but necessary kit components are Chinese doo-doo, but we all know that. The bike-drive chainring stamped onto the three-piece crank was as flat as a potato chip, the plastic throttle fell apart, the grips were something else, and the rear sproket and associated parts were simply missing. Thanks to Mike Simpson for sending me another post haste, and for the good advice about various things.

Truly, as a bicycle mechanic and a rank novice engine mechanic, my overall impression of the kit is that the best thing to do for someone with basic tools and expertise is to compile your own kit. Buy an engine, maybe buy a gearbox or make your own transmission, and buy the rest of the parts from the local motorcycle warehouse or on line - you'll end up buying a bunch of these anyway in the long run. I'm going to compile a list of necessary parts for my next build (addicted already), and will post it. Nothing against the kit vendors, but you know what I'm saying.

Finally, thanks to all the great advice and commentary I've been able to glean off here, even (and perhaps especially) when it conflicts. It's critical to get a bunch of views, then have to think about the situation for myself, then pick up the wrench and start monkeying around.

Looking forward to seeing more folks in Seattle out on the road. This is a blast!


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