About vespa px200 carb. problems......by Hong Kong user

Hello, i am Hong Kong Vespa user.
my English is not good, hope all of you can understand what i am talking.
i really want to make my px200 faster, so i have a little rebuild.
but Hong Kong have only few few people to re-equip the vespa,
that's mean no one know how to re-equip the car......
my car equip.:
vespa px200, 2001 front disk brake
malossi 210cc clinder kit
rz mark one rh
mmw 211cc clinder head
hp4 flywheel
bitubo shock
standard carb. with 135 main jet.
cut crankshaft, but non-port crankcase
here is my problem......the carb.
i have ordered a malossi 28mm carb full set , not reed valve one.
when i installed it on my car, my car have obstruct below 6000rpm......
it seems too many oil can't consume/use...
it is worse than the standard carb.
i have use 125 main jet, and change 122, but the problems still here......
after that, i changed the malossi 30mm with reed valve.
but the efficiency is bad!
the idle is ok, but the rpm cannot get the higher, obstruct really!
is that the jet/neddle problems?
do i need to change other carb.?
i have not port the crankcase, is this also a problem?
the car is in use everyday, and i want the stabilize idle and the power.
how to solve the problems? 
also, what do i need to change the part if i want the car more powerful?
thank you for your helping!

hi with regards to your  first set which is the 28mm delorto kit meaning not reedvalve rigth and your second set up is the 30mm reedvalve rigth? now your first set up problem is that you noticed there so many oil not being consumed rigth? now my question is what is the ratio of 2stroke and fuel did put on your fuel tank? im sure you know you have to mix oil since you get rid of your autolube with that set up. my analysis is you mix too much oil in your fuel tank, the ratio is 1 is to 10 thre abouts.

now with your second set up which is the 30mm reedvalve i suggest you follow slingdog you have to port the inlet port. malossi should have instructions on this. but then again try scooterhelp.com

hope this helps.cheers!


           for your 28mm not reed...200ml is too much for a 7 liters, your too reach mate. you just need 70ml for a one full tank which is 7 liters. you just need 10% of evry one liter. now for mmw reedvalve and a 30mm set up its going to be a lot of work on your inlet port. you need expert to do this. check out curare's blog on this forum. hope this helps. cheers. 

my px200 have been rebuilt.

the power is quite crazy...  2nd gear can also make wheelie.

thanks for all of guys helping!


i still have some questions.

the inlet port, have made it bigger for mmw2.

the port between engine and malossi cylinder, 3-port, have made it.

but one place still have not done,  between inlet port to the 3-port, near the crank place(like half circle).  i have not do anything at this place.  someone told me if this place made, the compression will loss and the engine cannot work......

i found most of the photo about reed-valve, all of the photo will port at these 3 place.  and my can only port 2 place...


can someone tell me that do i need to port the crank(half circle)place under inlet port?





can anyone teach me how to port the crankase?

inlet port is measured by reedblock/mainfold?

and the transfer port?  how to port it?  how to measure?


no one can do that in Hong Kong......


thanks for your help!

for my 28mm carb, i add about 200ml 2T oil each tank. 

is this ok?  someone suggest me increased to 200ml because my car will overheat.


i have been ordered a pwk 28/30mm carb and a mmw2 reedblock for my car.

now i need to find someone helping me to port the engine case, inlet port and transfer port.  no experience in HK, so it is very difficult to do this...

for pwk 28/30mm carb, can you help me how to jet it?  i also have main jet kit and the idle jet kit for setting.


will my car get stronger???..........

well......as everyone is away!

WHAT jets are in the carb? as if its straight out of the box, it will need to be jetted to suit your scoot

right them down and post them here,needle(x2/x7/x13   slide40  /atomiserav262av264 /main jet 122-135)

to use the reedvalve, you will need to open your inlet, or cut/buy the crank, as the reeds will open the port, not the crank.

also matching the ports on the crankcase will make a diffrence,

hope this helps



thx., i think i will choose reed carb.

can anyone recommend reed mainfold and carb. to me?



or i use malossi 30mm reed valve? 



hi match porting the crankcase is easy, just match the base gasket of the malossi kit on the crankcase. remove the exposed area of the case face that is not covered by the malossi gasket. or better you go to website scooterhelp.com. hope this would help.

rigth you have to open the inlet for the reedvalve. its also in scooterhelp.com