new pd18j carburetor

[eric29360]

I have a peace sports renegade 49cc scooter. I just bought a new pd18j carb for it. I put the carb on and tried to start it. It won't start. I put old carb back on and it starts fine. So i put new carb back on and it still won't start. Does the new carb come pre adjusted or do i have to set it up? I know it getting gas, it just won't start. Any help is appreciated.

[Ebuddy]

In my experience, it's a crap shoot. I've only ever replaced 2 carbs, but with both, I went through them pretty extensively (check the float, the holes in the jet, etc.) and re-set them up from scratch.

[skyrider]

After buying a non-returnable aftermarket performance muffler and air filter I got poorer performance (slower,louder) than stock, and took a good $100 loss selling the muffler on ebay. So I only get stock now. Unless you're a genius "mechanino man" like Bull or Blueboy or similar, I'd stay with stock.

[Shadowfire]

The key to more performance on a 50cc engine is one of three things:
1. Bigger bore. (=more fuel/air in each combustion stroke)
2. Higher engine RPM. (=more combustion strokes)
3. More air/fuel in your existing top end.

#1 may require a different carb/air intake/exhaust system to allow for the flow of more air (depending on where the bottlenecks are)

#2 is primarily impacted by tuning the CVT weights. You should really be looking to put the engine in its power band when doing this; faster isn't always better.

#3 is really only an option for 2-stroke motors (and is primarily affected by the exhaust pipe, and comes with its own set of tradeoffs), since the intake/exhaust valves in a 4T limit the airflow. In a 2-stroke there is a brief window at the bottom of the stroke where the intake port and exhaust ports are both opened, and a different resonator/muffler can change how much air/fuel gets pulled in at different RPM's.

You're not going to want to hear this, but I have to tell you. Putting an oversized carburetor does pretty much nothing for a 4T motor unless you are also putting in a BBK. You're wasting your time and money; the new carburetor does nothing that the old carburetor wasn't already doing.

[mmsscooters]

It will take 5-10 times trying to start it to prime the fuel lines and new carb, what air filter are you running? simple jetting, no bore kit, 18mm keihin, performance filter, 82 main jet. May differ on elevation and climate, cold=bigger jet, high elevation=smaller jet.