Hello everyone! I have a spare 21mm PWK carb that i would like to use on my engine because i cant find jets for the BoFeng (i can but for 20 euros i can get a new old style HT carb + jets) and i cant get it running right because of the main jet... Is it possible to fit it onto the stock intake with some reduction pipes and a rubber hose (probably??) and would it even work without the reeds. I seen somewhere that you need to drill out a little vacuum hole because the engine cant pull a strong enough vacuum to run on idle.
Carby Fitting PWK on stock intake?
- Thread starter MinimumVK
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GW's Motorized
Well-Known Member
I don't think it would work very well
do you think it would work better then the stock carb? The stock one had a defective main jet and its 4 stroking at full throttle when i reach 30km/h. If i open it up about half way it goes to about 45km/h but still 4 strokes quite a bit. Would anyone know what drill bit i would have to drill the jet out to get it to work normally? A lot of the times on Tomos mopeds we soldered the hole of the main jet and drilled it out with a 1mm drill bit to get a bit more power (tried it on the motorized bike but it made things worse)
GW's Motorized
Well-Known Member
I think you would loose performance or it might not even run at all. Just order a new JRL bofeng and a set of honda jets
20 euros for a single jet? Or is this a jet kit?
Chainlube
Well-Known Member
I would try just a .5mm bit.
I ordered a Reed kit for my bike so that i would be able to fit the PWK and hopefully get it running like it should. I will also window the piston that is already in it and just wonder if it would be okay to just drill a hole through the middle (like 10-15mm?) or would i need to cut out a rectangle? Asking this because i dont have a dremel. As for the size/postition of the rectangle i read that you just trace out the intake port. Is this done with the piston on bottom dead center? In the future a will also be looking at an expansion chamber.
Nothing wrong with a single hole. Just step it up in size instead of trying to bore it out all at once. Gives you better control. The shape can somewhat affect the power curve, but it's not a critical thing for 90% of people out there. I have done a single round hole myself a couple of times.
One plus to a round hole, no edges to snag.
So a little update about this if anyone would get some useful info...
About fitting the PWK carby without reeds: LA Hover Bikes did a video on it and got good results (you can search it up on YouTube).
I drilled a 15mm hole right i the middle of my piston, installed a G2 reed kit and a PWK carb on my first build bike. I jetted it to a 98 main and 32 pilot with the C clip on the middle notch and also blocked the power jet with a screw in the middle of the hose (at about 500m above sea level). Got it running very well and with my home-made pocket bike exhaust it reached a top speed of about 55ish km/h on flat ground. I was happy with it (until the coil gave out).
One weekend i also made an intake for a pocket bike carburetor so that i could run it until all of my parts arrived. It ran better then with my BoFeng but 4 stroked a little across the entire rev range but it did move. Would probably need to jet it right and make an intake with better welds so it was air tight (i welded it and used RTV on top since im not that good of a welder
)
Bellow are the pictures of the pocket bike carby.
About fitting the PWK carby without reeds: LA Hover Bikes did a video on it and got good results (you can search it up on YouTube).
I drilled a 15mm hole right i the middle of my piston, installed a G2 reed kit and a PWK carb on my first build bike. I jetted it to a 98 main and 32 pilot with the C clip on the middle notch and also blocked the power jet with a screw in the middle of the hose (at about 500m above sea level). Got it running very well and with my home-made pocket bike exhaust it reached a top speed of about 55ish km/h on flat ground. I was happy with it (until the coil gave out).
One weekend i also made an intake for a pocket bike carburetor so that i could run it until all of my parts arrived. It ran better then with my BoFeng but 4 stroked a little across the entire rev range but it did move. Would probably need to jet it right and make an intake with better welds so it was air tight (i welded it and used RTV on top since im not that good of a welder
)Bellow are the pictures of the pocket bike carby.
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Is there a reason you blocked the power jet?
