1p39qmb 50mm bore jet size?
 

I have a 1p39qmb and a 50mm bore kit and a ported head 69mm valves 22mm carb 150cc intake manifold ported. but don't know what jet size to use.

No exact answer and results vary like climate , altitude , exhaust and if you modded the airbox or installed a Uni or K&N . I used a 95 MJ with my 50mm BBK since I live near mountains and its so darn humid .

I would get a jet kit instead of paying per jet price . PFS has one but their site seems to be down at the moment . Here is another source for a jet kit http://enviromoto.ecrater.com/p/4129...jet-set-gy6-50

using the stock airbox with the black part of the stock filter use 98 jet 44mm bore

22mm is probably a bit very large for that set up, I use a 19mm carb w #94 main #38 pilot, standard intake and cone-paper filter on my 50mm BBK

intake port on my head is bigger than a quarter same goes for the exhaust side.

https://mail.google.com/mail/?ui=2&i...7786-local1&zw https://mail.google.com/mail/?ui=2&i...7786-local0&zw

well i but the kit on ran a 40 idel jet main jet drilled that sh#t out 1.20mm was to big 1.00mm didnt even try it to small. drill bits from manards tryed a 55# that they had and it works some what needs to be a bit bigger.

Did you use the spacer on the intake ? A buddy built a 50mm with large valve and ported head but used a 24mm without the intake spacer , Uni and a performance exhaust .

Jetting is a trial and error series of testing but once you get it dialed in well worth it .

If you have the cabbage you can go with EFI www.ecotrons.com

yeah this guy is using the spacer just made the hole bigger

Here is a cheaper jet kit that work on the 22m but if not they have on for the GY6 as well http://www.partsforscooters.com/114-...ategory=133078

I run a 95 main, with an 18mm carb. Does well so far....Alohaz

looking for more top end some where around 70 to 75 and putting in a cam. just not share witch gear to run with 10" tire at some point will go bigger rim and tire just not now.

also run mine at 95 and its perfect