The TM34-2 is supplied with the following factory jetting installed:
Pilot jet 50 (VM22/210), Needle 5FP17, Needle Jet Q-2 (389 Series), Main Jet 280 (4/042), Air Jet none, Slide 4.0 (832-39012)
Dimension A= 40mm, B= 83mm, C= 160mm, D= 58mm, Total Width 78mm
Unlike many motorcycle manufacturers’ purpose modified versions, these factory TM Round Slides are both 2 and 4 stroke compatible and are regarded by the factory to be the best performing version of this carburetor ever made.
Mikuni’s (flat slide) carburetor, the Mikuni TM Series Carburettors provide significant performance improvements over older round slide carburetors. Air flows faster and smoother through the TM Series venturi due to the flat slide design and the jet blocks which help create smooth bore effect.The high velocity of the air flow means a stronger vacuum at the needle jet providing more precise metering and better throttle response.
Performance features for the TM Series Carburetors include a large selection of bore sizes for increased fuel mixture flow to match engine modifications. And the TM Series offers a wide range of tuning components to allow precise fuel mixture metering in any application, at any throttle setting, under any riding conditions.
Tuner jet kits can be purchased separately for many different motorcycles as per the corresponding options. These kits consist of the suggested jets for changing that are not matching those factory fitted in the TM34-2, they include an extra one size up and one size down main jet for tuning the main circuit due to fuel quality variations, altitude and climate. Testing and conformation of correct main circuit jetting can only be done by physically changing jets and WOT testing.
These tuner jet sets have been determined from thirty years of experience, customer feedback, plus research and development as the Australian Mikuni distributor. From time to time these may not be exactly right for every engine, usually due to changes to porting, compression or numerous other things that contribute to the requirement for additional fine tuning but as a rule our kits are spot on or a very close and useful starting point, but we give no guarantees and sorry do not release kit details or jet size information. If you have your own spec simply purchase the carb and buy any other required jets from the jet pages. This also applies to replacing jets in other TM34’s as the 389 series needle jet and others items may not match and fit.
Keep in mind that these are suggested specs, and all tuning procedures, as found in our Tuning Tips section must be adhered to for the confirmation of any supplied jet’s compatibility with your engine.
(The picture with the cable shows the required length of inner cable protrusion and securing fitting at the carb end on basically a minimum length adjustment. The back board is divided into 1 and 10mm increments)