Turn your Huasheng 142F into a Fire Breather

Discussion in 'General Questions' started by Scootmeister, Oct 2, 2014.

  1. Scootmeister

    Scootmeister Member

    I have been riding my HS-powered bike for several years now. Originally, I rode with a direct chain drive, but performance was marginal. I finally broke down and bought a SBP shift kit and added a Shimano 3 speed
    hub and my takeoff and top end improved, but the engine was still anemic, even though it is dependable, quiet, and easy to maintain. Last week I bought a SBP free flow air cleaner and even though it is pretty narrow, it was a tight fit. The engine obviously was running too lean so I started researching how to re-jet. I finally found a go kart website with excellent instructions for drilling out the stock jet on the stock carb. I know you have heard a lot of advice about how to get more out of these little engines. Do yourself a favor. Get a set of wire drill bits with a range of #60 to #80. Remove your carb and pull the jet. Carefully drill out to .260 (#70 or 71) and install a free flow air filter. Attached is a picture of the moped air filter I used. I fabricated a mount from a 3/4" chrome flange for a handrail for a boat. It is 45 degrees so it allows the cone filter to clear the center post. I centered the center hole for the flange over the stock filter and marked the mounting holes. I drilled the mounting holes to match the pattern of the carb. The same bolts hold the carb and the flange to the intake port. The chrome flange was $4 from a marine salvage ship and the cone filter was $11 online. The engine gained noticeable horsepower and the filter can now be changed by simply removing the hose clamp. With the SBP filter, I had to remove my engine to change the filter. The difference this modification made is amazing. It's still not a screamer, but at least it's not a crawler anymore. I don't need to over rev the engine because of my gears, so I don't expect serviceability to suffer.:idea:

    Attached Files:

  2. Scootmeister

    Scootmeister Member

    DSCN3390.JPG DSCN3391.JPG DSCN3392.JPG An update. I installed a brass fitting for the small hose that carries air from the crankcase to the air filter. The fitting is threaded so I used a die with pipe thread.
  3. RollingStones

    RollingStones Member

    Haha I understood nothing of what happened. :eek:nline2long:
  4. Scootmeister

    Scootmeister Member

    Hey Rolling Stones. All you need to understand is that these engines offer a lot of advantages but they are tuned to run water pumps and other industrial equipment. When you re-tune them by opening up the air intake you get more power and higher speeds. The stock air filter is very restrictive and prevents the engine from performing well. I simply removed this restriction then drilled out the jet to allow more fuel to flow. More fuel and more air means more power. Part of the fun of this hobby making a silk purse out of a sows ear! With the re-tuning and the 3 speed shimano hub, this bike now rides like a small motorcycle.