Genuine Japanese made Mikuni TM40-6 (HS40) Factory aftermarket Racing Division Carburetor.
The Mikuni TM40-6 (HS40) is supplied with the following factory jetting installed which will only run on a Harley Davidson and needs a total re-jet for all other applications:
Pilot jet 17.5 (VM28/486), Needle 9DJY4-96, Needle Jet Y-6 (568 Series), Main Jet 165 (N100.604), Air Jet 1.1
Mikuni TM40-6 Dimension A= 44mm, B= 100mm, C= 165mm, D= 55mm
Going fast has never been so easy. These carburetors can be adapted to a number of different applications from single to multi-cylinder engines, giving better throttle response, improved acceleration, increased horsepower and torque. In a number of instances Dyno tests have shown improvements of up to 25% when fitted to same size CV carburettored engines.
The HS40 carb has not been sold as a Harley Davidson kit as such for over twenty years, but as a testament to the quality of the carbs themselves and the kit components many happy customers are still using this set up. Though no longer available as a Harley kit we do have complete replacement new carbs available and also a range of replacement spare parts and rebuild kits.
The in carb jetting is suitable Harley twins around the 1000cc upward engine capacity where purchasing one size up and one size down in the main jets to be able to fine tune the top end would be an adequate starting point. Be warned though that for fitment to big singles does require the replacement of nearly all the jets to perform properly and where the need for sleeves on either the inlet or outlet spigots is also required to match most OEM carb sizes, you are far better off to look at our specially built kits. This carb delivers exceptional performance improvements on any 4-stroke single engine over 500cc and on any 750 to 1200cc twin that they will physically fit to.
Compare your existing carbs dimensions against the A, B and D above for direct replacement compatibility and study the pictures taken on our graph board (the black lines are at 10mm spacings with 1mm increments in between), to determine available space if fitting in an unpublicized application.
With an unmatched air-cleaner spigot diameter or carb length and if still wanting to use the OEM air box rather than a Pod, check out our “Air-cleaner adapter listing”. If you can’t find a match, the manufacturing of special sleeves or extensions for some applications may be necessary. This is easily done by your local machine shop or any muffler shop with a pipe expander and the results far surpass the inconvenience.
If your OEM cables don’t match and if not available in our “Throttle and Cable assembly list”, you may well also need to have yours modified or new ones made for your application.
(The picture with the cables shows the required length of inner cable protrusion and securing fitting at the carb end on basically a maximum length adjustment using the outer two holes on the rotor. The back board is divided into 1 and 10mm increments)