Mc-16-50 1P39QMB

[ratracing]

Give me ideas opinions if it's about performance I'm looking to build a sleeper so far I'm running stock transmission stock muffler and engine only mods is. Advance Timing ,HP Air filter ,Blue box Racing CDI, HP Orange Coil, anymore question ask I want some opinions fellow scoots

[niz76]

WELCOME!!

You're in the right place!
Many folks here modding the 139QMB 4 pokes... A Big Bore Kit is the best "bang for buck." The 70cc BBK's are easiest on the stock crank which is a weak point. There are some big BBK's out there but many reports of broken cranks to go along with them. Other mods include cams, big valve heads, stroker cranks, high compression pistons, CVT upgrades and tuning etc. If you want to go REALLY fast- swap a 2t in under that scoot! ;P hehehehehe

Advanced timing AND a Blue CDI?? Sounds dangerous! Make sure to upjet for the open filter if you haven't already!

[ratracing]

What jet do you suggest for my setup ? i thought a #90 main jet

[ratracing]

[90GTVert]

Mar 29, 2016 20:06:11 GMT -5 ratracing said:

What jet do you suggest for my setup ? i thought a #90 main jet

I suggest many jets, and then a tuning process.

www.49ccscoot.com/faq/carbtune.html

[underbone]

I'd sub the thread if I could. How did you advance the timing?

I'm working a 139QMB build now. Target is 55mph.






I'm liking the 24mm carb and intake I got off the bay for $27. Check out the vid.

[90GTVert]

Mar 30, 2016 5:40:04 GMT -5 underbone said:

How did you advance the timing?

I'm working a 139QMB build now.

I know it wasn't addressed to me, but this may be useful to you :
youtu.be/p63JXW29tVo?t=9m31s

[ratracing]

Thats definitley a good start but not an agressive gain unless followed by other mods and tuning.Manual Advance Timing is a blessing