Which jet.

[alan34]

Hello there to everyone.can someone please advise me on a jet question I have a 2006 Px 125 cataized.ive taken off exhaust and added a sito plus exhaust the trouble I have is bike runs ok 45mph but is bogging down on pull away I've uprated to98main jet that seems ok plug not a bad colour at 45 mph. Bit at tick over plug is black and sooty.i have richen the mix on the air screw which helps but seems to rich. Should I change the idle jet but YouTube says change idle jet to give more adjustment do I go up or down on jet size thankyou to everyone for your help cheers alan.

[phattanglo]

Hi Alan,
My 2012 125 is now running a Scootopia big bore exhaust , which I guess will be similar to the Sito plus.
I have changed my jetting to an earlier spec as the Euro spec was jetted to run lean to get through emissions.
If your plug is black at lower revs then it running too rich.
Basically it needs to run as lean as is safe by adjusting the pilot screw until the engine revs smartly when the throttle is blipped, but comes back down to tickover quickly.
if the revs take a while to come back down to tickover , then it's either set too lean, or there is an air leak somewhere.
What you want is a nice quick response up and down and then adjust the pilot screw until it's just a little bit richer just for safety.

This is what I changed to on my mine.
Drilled air filter
Pilot jet 55/160
Mixer stayed as a BE5
Air corrector 120
Throttle slide Number 8
Main jet 98.
I don't say that this jetting would be right for your scoot as every engine is different, but for mine it seems to run ok and I'm confident that it shouldn't nip up as the jetting is a bit richer in the lower revs which is where a soft seize can happen when coming off full throttle, in fact I could probably get away with putting the 96 main jet back in, but I'm happy with it as it is.
Hope this is of some help.

[alan34]

Hello pantanglo thankyou for your message I've a 98 main jet instead of a 96.and have ordered a 55/160 idle jet going to put that in and hope it rides better at low speed without stuttering. if it's to rich I'm hope to lean it out with mixture screw I'll let you know how it goes cheers alan.

[soulboy74]

You should have tried running as is with the 96 main jet before going bigger !! I have the same PX just Euro 3 model what is a good way round the exhaust issue is your exhaust system two peace or one !! If it is the latter like mine just change the cat part with the manifold down pipe and keep your settings standard or drill the holes in the air filter and go up just one on the main jet that's what I did and it is running well hitting 50+ ish and pulls well through all the gears !! Now theses exhaust system are made really well for our modern PX and you won't get it better than just a bit of standard 👍l just done a 150 miles round trip last weekend and I didn't have a issue just a pain in the rear LOL best foot forward soulboy74 🏴󠁧󠁢󠁥󠁮󠁧󠁿

[alan34]

Hello there cheers schoolboy for your reply. I think my original exhaust does split so going to do what you did thankyou very much for your help cheers alan.

[alan34]

Sorry I mean soul boy. 👍

[soulboy74]

Yes good choice the manifold down pipe you want to be looking for is a gainilly type or something similar l think there's a couple to choose from as these exhaust system are very well made for the PX and once you get the filter drilling don't you might not even need to change the jet straight away but I only went up to 97 main and you can really feel the difference ! I think unless you're a speed freek you will injoy your scooter knowing that standard will give you years of reliability 👍 best foot forward soulboy74 peace and love

[alan34]

Hello there thankyou soulboy for your help sound advice I only want it running smooth safe riding cheers alan.