50cc Power & Speed

[buddyearl]

My 50cc has a 72 main jet and a 35 idle jet. I want to put in a 78 main jet, do I need to put in a larger idle jet, if so what size?
Also, by going to a smaller weights will that give me more quicker acceleration?

[felliott]

If your idle is fine do not touch the idle jet. Yes less gram weights will help you have quicker take off.

[buddyearl]

Have you tried the weights by Dr. Pulley? How do you know which ones to use? I looked at Monster Parts and they list different sizes like 15x12 etc.

[Deleted]

you want lighter in weight not smaller in size.

[Deleted]

5.5g usually is the perfect all around weight

[skuttadawg]

Would try between 72 to 78 like in a jet kit like this eshop.mainelyscooters.com/product/cat-139qmb/139qmb-gy6-carburetor-jet-tuning-kit/ as its better to have more options with leftovers should you make any changes like unrestricted exhaust and need some then as well . Do you have the stock carb ? I would replace it if so with a carb that you can adjust the needle position and air/fuel screw where the sealed factory ones you can not adjust to fine tune and run lean . Here is another enviromoto.ecrater.com/p/4129835/naraku-main-jet-set-gy6-50 . The first site has several carbs should you want one .

Does it run good and you just want to speed it up ? Run your scooter down the road at WOT for a bit and come home , let it cool down and remove the sparkplug and compare it to this chart to get an idea of how it is running before you make any changes . Here is the chart www.4secondsflat.com/plug_chart.html there is more info there as well .

Idle jet is replaced if you have trouble idling or bogging on take off with the main jet for more top end . Here is a link that explains carb theory that may help you and others www.iwt.com.au/mikunicarb.htm

I had a TaoTao ATMa 50 that was a " secret 63cc " and ran a 90 jet with stock exhaust , airbox and a 50mm or 82cc BBK . Unsure on what the 63 had as I cracked a piston the 2nd day I had it and again 6 weeks later . Told my scooter dealer I did not want another POS piston and he sold me an Air Sal BBK for his cost and no labor to install since under warranty .

It came with 8 gram rollers , I weigh 200lbs and its very hilly here as my area is called " The FootHills " as I can see mountains from my home . I went with 5 gram rollers and wow takeoff and uphill was so much better and did not lose top end since it had unlimited CDI unknown RPMs since no tach . Remove the roller weights and weigh them on a scale to see what you have first . Not all scooters even the same brand and model will have the exact same weights in them . If you for example have 8 grams and bought 6 grams and the were too light and you over revved , you could mix 3 6 grams and 3 8 grams to equal 7 grams . Once you know the weight amount that works for you get 1 gram less in Dr Pulley Sliders . DRP sliders have more gear like ratios with a more steady climb in acceleration , last much longer , no worry about flat spots with round rollers , last much longer , may go faster as I went from 12.2 gram rollers to 12 gram DRP and gained 5 mph on top end and just a hair less on take off but still fast , and best of all , the do not have the annoying roller rattle noise . I thought it was a bad crank bearing(s) at first until I read up and listened more closer .

Most replace the fuel and vacuum lines with automotive fuel hose , fuel filter ( like the see through with golden cone that darkens when dirty ) install a NGK with option of the iridium one , a larger main jet ( with variables like altitude and climate so results will differ , lighter roller weights and a Kevlar drive belt . All with help performance and reliability and be 50 or less for all the parts .

To truly get more power a BBK is the way to go