Run the engine with the stock main jet and take a plug reading. If it's lean and you need to increase the size of your main jet, drill the jet out with the next size larger drill bit, which in this case is the #60 bit. Run the engine again with the drilled out main jet and take another plug reading. Repeat this process until you get a good plug

There is no rule for jetting only general trends, intuition, direct measurement, comparison ect. Best way to tune without a dyno is to change something little by little and if you like it better when you change it keep it n vice versa while making sure to consider performance overall, if you move the clip and it runs so much better going from partial throttle to full but gets ruined when you

Ok, ada yang tanya kat komen macam mana nak test main jet dan pilot karburator. Untuk cari main jet pilot yang tepat ada beberapa teknik terserah kepada kepakaran masing-masing. Secara umum diketahui ramai, tekniknya ialah: Test full throttle gear 1,2,3 kemudian terus matikan enjin. Tunggu enjin sejuk barulah buka plug dan lihat warna plug
Setting Main Jet Setting main jet pada karbu vakum standar akan berguna jika anda menggunakan knalpot racing atau sudah menggunakan CDI aftermarket. Jika tidak menggunakan knalpot racing ataupun cdi aftermarket maka tidak disarankan mengganti main jet, dan tetap menggunakan main jet 115. Kemudian, perhatikan juga rasio kompresi mesin. Needle Jet 175-P-0. Pilot Jet 27.5. Main jet will be between 180 and 240. Needle the same. Position, start in the center and go from there: 1973 RD350. VM28 Stock Carbs. Uni Filter, Stock Air Box. Stock Carbs. VAPE Ignition. Rebuilt Engine. Stock Exhaust. Needle Jet 175 0-8 (stock) Pilot jet 27.5. Main Jet 140 (stock) Needle clip position as PT. INDOMOBIL NIAGA INTERNATIONAL 2W SERVICE TRAINING ADVANCE KARBURATOR Bypass Bypass Pilot outlet Pilot outlet Pilot jet Pilot jet ( 1 ) ( 2 ) 14 PILOT SYSTEM 2. TIPE LUBANG GANDA. PT. INDOMOBIL NIAGA INTERNATIONAL 2W SERVICE TRAINING ADVANCE KARBURATOR Jet needle Main air jet Needle jet Main jet 15 MAIN SYSTEM. PT. . 483 49 28 309 324 23 239 444

setting pilot jet dan main jet