Engine Upgrades?

Dimmizer

New Member
May 18, 2020
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Hello Bicycle Motor,

I'm not a motor bicycle enthusiast but I do have a 49cc Huashengtaishan 4 Stoke engine like so

high-quaility-motor-2015.jpg

I was wondering.. is there anything I can do to upgrade this engine? I've been looking all over the place and I can find big bore kits and such for 2 stroke engines but these 4 strokes have nothing it seems.. does anyone have more information on this?

Thanks for your time and I'm sure I'll be frequenting this site often for any tips n such.
 

Venice Motor Bikes

Custom Builder / Dealer/Los Angeles
Mar 20, 2008
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Los Angeles, CA.
Welcome to the forum... Sorry, but there aren't any real performance products for those little engines.

What I would suggest is to find a large foam air filter that you can adapt & to fabricate a straight pipe exhaust... after that you're going to have to install a larger jet in the carburetor
 
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Dimmizer

New Member
May 18, 2020
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Welcome to the forum... Sorry, but there aren't any real performance products for those little engines.

What I would suggest is to find a large foam air filter that you can adapt & to fabricate a straight pipe exhaust... after that you're going to have to install a larger jet in the carburetor
Thanks for the welcome and thanks for the advice :) I'll look into this for sure.
 

user53399

New Member
Oct 10, 2019
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I removed the silencer from muffler and drill it, and enlarged the exhaust header to reduce back flow.
Open inlet in D shape (almost oval), removed the back cover of the air filter and also the small cover inside the filter (from oil breather), and kept the foam.
On the carb air choke I reduced the middle plastic to get more air.
After that the carb asked for 2 and a quarter turns to get the best mixture possible with stock carb.
The results are more torque from when it starts rolling to top end speed.
Where I live there are lot of up hill roads and from stock I noticed very good improve getting 44 mph instead of 35 mph stock top speed, and in up hill roads 25 mph instead of 12 mph stock.
These mods are all from Graham Bell book, and information collected after riding my skelha stock, I made these first modification to know the direction to take from here, which is clear at the moment to improve breaking power.
After that its possible to change to bigger carb with better inlet manifold, and better exhaust system.
 
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