• anyone here tried 30mm pwk on a 125r ? (cleaned up ports , boyesens , full DEP , head work , enlarged airbox snorkelhole ca Twice the area ) looking for a starting point in main and pilot jet sizes just to get an idea of which range of jets i will have to buy ?


  • @Dingle74

    I have no idea mate, however, jetting kits are often very inexpensive on aliexpress and wish, u can get 10 main jets for around 5 pounds, i just went on and bought an assortment of different jets cause they were so cheap, however, im not 100% sure on how accurate they are etc, a 172 main jet from aliexpress might not be the same as a polini 172 main etc


  • @Arild i know that , its just the deliverytime from china that bugs me , just needed a pointer in the right direction , no point in waiting 20-40 days to save a 5er on maybe 2 kits thats never gets used if someone been there already and could give a hint 😁

    i do have a mikuni hex mainjet to boresize chart but i dont know if its that simple when switchin from TM to PWK (ex mikuni hex 280 = size 144 keihin )

    and another thing i cant get my head around : PWK pilotjet sizes VS Mikuni TM , at the moment im running a fairly rich pilot om my TM (27,5) but what would that equal to in keihinsizes as they uses larger numbers , smallest pilot i could find is a 30

    but thanks for the input


  • @Dingle74
    I see u mate, i cant really help u in that aspect, firstly i dont have a clue u should aim for since our setups are very different, and secondly, what might run good for me over here in sweden might not work out for u wherever u live, owell, id just buy a couple of kirs for cheap but with pretty quick shipping to so u can experiment and get exactlyy the correct jets for ur specific bike and setup


  • @Arild over here in sweden is not far from me here in denmark , so what ever works for u might work for me aswell 👍

    i just have to go the old trail an error-route

    thanks again for input


  • Jetting should be done to suit....

    However, that's mainly when you need 100% performance. And every 0.X bhp counts.

    I don't know what Yamaha jetted for your vehicle in your country, but did it come with 240 main mikuni jet? If so, then that's the same as the UK. Whilst not providing maximum power, it's a good place to start.

    So finding something that roughly matches OEM settings and going from there would be a good starters for 10.


  • @calum

    problem is im changing to a pwk type carb and they use boresizerated mainjets where the mikuni is using flowrating so cant use current jetting as guideline as there is too many unknown variables (well ,for me) thats why i needed a hint from someone who had tried pwk type on a DTr

    but i think i have to bite the turd an just order a boatload of pilot and mainjets and maybe a needlekit and take it from there


  • Hi, use a K135 main jet with a K38 slow jet for a mildly ported 125.


  • @theportingmaster

    Thanks alot , just what i wanted to hear 👍 it narrows down the "to buy" list

    where u running with or without powerjet circuit ?