doesnt start with stock air box...  By  needspeed (Read 435 times)

It gets vacuum from the intake to the pecocks diaphragm which acts like a fuel pump . What size engine a 50 or 150 ? What size carb and the idle and jet size ? Stock scooter is lean and if you removed the air box lid and let the carb alone it will bog so bad that you can not drive it . I played around ans tried this with 4T and a 2T 50 in my driveway just for kicks . Both started , was louder and would idle but I did not leave the driveway . Many drill 2 or 3 3/8 or so holes in the airbox to increase the airflow . I have also seen a scoot with 2 holes drilled into the muffler to increase the exhaust flow and was rejetted for the mods .

With a less restrictive air filter like K&N screen or a Uni foam airfilter a larger main jet is required to make it run right . This involves trying a few diff sizes in order to fine tune it . Since yours runs good with the mod but not the airbox you would need to drill some holes or use a smaller main jet .

When my 2T was a 50cc I went from a 68 to 75 main jet and it ran good . I bought a Uni vent cover which is much smaller than the big red air filter and upjetted to a MJ and it had more torque on takeoff and midrange , with more air being sucked in it was louder . Bought the normal Uni but my dealer did not have any jets for my carb larger than a nor did any other shop . Well impatiently I put in on and only went around the block as it idled ok but had some bog but it seemed like it was not enough to hinder it much . I went down the street and the darn thing soft seized and I had to push it home darn it .

I later installed a 47mm BBK or 70cc , installed an unrestrictive exhaust and first tried the small Uni . It bogged like it was not getting enough air instead like it does if lean which is not enough fuel . I had also installed too large of a main jet and it would spit gas out of the carb . I swapped out for the red Uni and a smaller main jet and it was amazing how much better it was . It started up fine but sometimes it would stall while idling unless I hit the throttle a bit . I replaced the 40 idle jet with a 45 IJ and now it starts without having to give it a sip of throttle and idles with no stalls .


Remove your sparkplug and compare the color with this chart to see how the jetting is with the mod before using the airbox stock or modded www.4secondsflat.com/plug_chart.html Use this info as a base to start on so you can compare a smaller jet or drill two holes . Jetting is a trial and error series of tests , so have a lil patience and enjoy it once its dialed in

So im still at the doesnt quite leave the driveway situation ...
Well it leaves but cuts out , boggs or something ....

yes i am very new with these things , but I figured they were simple like and here I am ... hehe

I have to check the clutch /variator or whatever .......
it idles ok , revs at idle up a little high before engagement ...
then its kinda jerky,then boggs or cuts out due to load it seems...

? what did i change ? well prolly lots of things......
adjusted carb screw , had 'custom air tube and filter' on there cause it would start up and idle real easy , but it seems to cut out right away .......
I know there are lots of articles on carb tuning out there , but then i would be reading the basics forever
certainly i am gonna continue reading , but THANK YOU ALL for the advice and suggestions so far

apparently I have upset the delicate balance

I would like to try to run an aftermarket air filter setup , for a little more response ,but gonna need it to be reliable .........

its a 150 bashan peace ..--..---
lol

been sitting , i added some gas treatment , runs and smokes a bunch ...replaced stator, changed the oil, gonna try to run this thing


Can the clutch thing stick , cause it to stall??

I removed the belt cover , and found the broken kick star bushing ....
replaced the kick start stuff-- hopefully it inst causing issue s

other wise must be the carb
suppose i could adjust the a/f screw a little

Looking to test run this scoot tomorrow ;D