ok i am truly confused a std jet size for a 125cc is 210 then wen you fit a dep or mod the air box you go up maybe to a 240. but the std size for mine is a 150 i thout this was wrong (but it isnt) so i put in a 290 jet. but was told that would be to big and was given a 180 to try but the hole in the 180 is twice the size of the 290? any help on this one would be good. thks
Maybe you have a different carb or something? I know people say they are bigger and you say 150 and my carb has a 132 main jet according to the manual. My bike is a 1996 dtr engine but a different Carb i guess since KTM own the bike not Yamaha.
The number on a jet relates to the fuel it will flow, not the hole diameter. If youve drilled it and it works then that's good!! In reality, each jet size represents a difference in hole size of a few microns (1 micron = 0.001mm) and it will be difficult to drill accurately.
The jet sizes are very confusing and I still scratch my head when I read the Haynes manual. The 26mm round slide carb has different jet sizes to the 28mm carb. Even the 28mm has different jet sizes between years!! A DEP pipe shouldnt need re-jetting according to DEP if I remember correctly. It doesnt hurt to go up one size, as it will help it run a bit cooler without affecting the power too much and makes it less likley to heat seize. Always do a plug chop if concerned. Hope this helps
ok the thanks evre 1 the bloke in the garage gave me his box of jets to take home and try to see witch is best. just waitin on my reeds to turn up to give it a try.
In reality, each jet size represents a difference in hole size of a few microns (1 micron = 0.001mm) and it will be difficult to drill accurately.
