I though i would just post these pics to help, although i still don't know why I would make the bike run a little richer... The motor is running fine before removal, higher rev?
Removing welch plug HuaSheng 49cc 4 stroke
- Thread starter Mike_Honcho
- Start date
That's a idle circut screw.... Without it you will have a lot of trouble making the engine idle & run properly.
That "was" an idle circuit screw. It did have a driver slot to adjust it. The counterbore just to the right is the plug you wanted.
Norm correct me if I am wrong.
Carbs a cheap. Welcome to the club.
Tom from Rubicon
Norm correct me if I am wrong.
Carbs a cheap. Welcome to the club.
Tom from Rubicon
You're correct.... that was a idle screw!
Actually, this would be a great time to swap out that carb for a 2-stroke carb conversion!
He removed the correct plug.
The plug covered the air mixture screw.
Do not remove the plug in the counterbore just to the right.
Norm, I have a first build HuffyDavidson with carb trouble. What 2stroke carb do you recommend?You're correct.... that was a idle screw!
Actually, this would be a great time to swap out that carb for a 2-stroke carb conversion!
Tom from Rubicon
Tom, this is it... https://www.gasbike.net/collections/4-stroke-parts/products/4-stroke-nt-carburetor
This is a much better manifold... https://www.gasbike.net/collections...s/49cc-nt-carburetor-intake-for-4-stroke-long
If you use this carb?, you'll probably have to install a slightly larger jet. (or just drill it if you can get a 'jewlers' drill bit set)
Thanks for the info Norm. what diameter drill. I'm a Tool and Die Maker with many drill sets.
Tom from Rubicon
Tom from Rubicon
Stock NT jet is a 70 so try a #69 drill bit
Use number drills.
#BitSize Inches Millimeters Jet Size
#80 0.0135 0.3429 34.29
#79 0.0145 0.3683 36.83
1/64" 0.0156 0.3969 39.69
#78 0.016 0.4064 40.64
#77 0.018 0.4572 45.72
0.5mm 0.0197 0.5 50
#76 0.02 0.508 50.8
#75 0.021 0.5334 53.34
#74 0.022 0.5715 57.15
#73 0.024 0.6096 60.96
#72 0.025 0.635 63.5
#71 0.026 0.6604 66.04
#70 0.028 0.7112 71.12
#69 0.0292 0.74168 74.168
0.75mm 0.0295 0.75 75
#68 0.031 0.7874 78.74
1/32" 0.031 0.7938 79.38
#67 0.032 0.8128 81.28
#66 0.033 0.8382 83.82
0.85mm 0.0335 0.85 85
#65 0.035 0.889 88.9
#64 0.036 0.9144 91.44
#63 0.037 0.9398 93.98
0.95mm 0.0374 0.95 95
#62 0.038 0.9652 96.52
#61 0.039 0.9906 99.06
1mm 0.0394 1.0 100
#60 0.04 1.016 101.6
I usually drill two sizes bigger, but your engine might want something different.
If you feel you've drilled too big?, you can easily close the jet hole with a pinhead size dot of electrical solder & re-drill it to a smaller size.
If you feel you've drilled too big?, you can easily close the jet hole with a pinhead size dot of electrical solder & re-drill it to a smaller size.
Hey Norm,
#68 drill is logical, .003 larger won't over feed the engine.
Run it and give the sparkplug a hard look.
Been screwing around mounting Wald fenders on my Sportsman 80. Thanks for the input. Hope Mike is absorbing all this good info.
Tom from Rubicon
#68 drill is logical, .003 larger won't over feed the engine.
Run it and give the sparkplug a hard look.
Been screwing around mounting Wald fenders on my Sportsman 80. Thanks for the input. Hope Mike is absorbing all this good info.
Tom from Rubicon