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Old 05-18-2016, 08:55 AM
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sbest sbest is offline
Motorized Bicycle Elite Member
Join Date: Nov 2015
Location: Nova Scotia
Posts: 248
Default Re: Would anyone but me buy a smaaler still China Girl?

I like the idea of smaller lighter and quieter, but it will be harder to sell the idea of less displacement to the US market. Most jurisdictions specify less than 50cc and 20mph so there are pretty good target goals. So how to make it smaller lighter and quieter?

A large weight reduction is in the flywheel. Aluminum cheeks with steel weight rings on the outer diameter could reduce weight 3-4 lbs in a standard China Girl. Thinner precision casings and plastic covers would take 2-3 lbs off and reduce all dimensions 1" in every direction. BMX chain and aluminum sprockets. These things would double the price of production.

The plastic gear and chain covers would dampen a lot of their noises. A new air filter cover and fine foam filter would quiet a lot of the intake noise. Rubber pegs between the cylinder and head fins would quiet those noises.

The exhaust would be a pipe tuned for max torque at 20mph and +50% over-rev so extra pedaling would be rewarded with up to 30mph speeds but still meet the legal 20mph condition on flat and up hills. Ideally the torque tuned pipe would be thinwall construction with a surround type muffler to quiet it to a whisper.

The beauty of this approach is that each component would still interchange with all the 50cc and 66cc motors that are still out there. Development could start as aftermarket sales of individual components as a complete package is developed.

Think about it;
meets all legal requirements, 50cc, 20mph flat speed
will haul touring weights up hills
can still pedal or down hill to 30mph
whisper quiet
half the weight due to precision thinwall castings and aluminum/steel hybrid crank
1" smaller in all dimensions
Complete interchangability

Will someone build this?


Last edited by sbest; 05-18-2016 at 09:02 AM.
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