Need carb advice

[lennonfan007]

My airbox recently was rendered useless on my chinese 50cc gy6. I had an open-air cone filter laying around and decided that would be a good opportunity to install it, but I would also need to upjet. I currently have a 90 jet in and a jet set on the way. What size jet would you recommend? At this point I realize no amount of adjustment to the carb with the 90 jet would stop it from running too lean to ride safely.

[Lefty]

If that is the only mod on the scoot that #90 is to big. If the cone filter is the only mod a #80 or even smaller main jet. I assume it is the stock carb an 18mm and they come with very small main jets you may even need something in the 70s range.

So for your question yes you can ride it but it will not run to great To much fuel.
Lefty

[skuttadawg]

Your best bet would be to get a jet kit instead paying per jet prices . Here is a jet kit http://www.partsforscooters.com/114-49-QMB139-Main-Jet-Kit?sc=34&category=133078

Most have the fuel/air screw covered up and no clip to adjust the needle position so a carb you cab tune would be a great buy . Here is 4 diff types that come on the Gy6 50 http://www.partsforscooters.com/Street-Scooter-Carburetors-and-Parts

The airbox does not choke the airflow so a cone airfilter with a stock head and exhaust will surely make it leaner and not perform well like it would on a BBK , ported head or unrestricted exhaust . Remove the sparkplug and compare the color of the tip to this chart http://www.4secondsflat.com/plug_chart.html If you get the jet kit or other jets once you think you have it dialed in install a new sparkplug , run it down your strett hitting the top RPM and hit the kill switch . Remove the plug and compare it to the chart above .

[lennonfan007]

It had run with with the airbox and the 90 jet flawlessly, but with the cone and a new spark plug it was clearly running way too lean, and it heated up way too quickly.