Mikuni TM-40 Carburetor
I am amazed at the amount of change in idle quality and throttle response this carburetor has made. I had put the jet kit in my stock BST40 carb and that made a major improvement from stock needle and jetting. But I still had random stalling at traffic lights or stalling when there was a fast throttle return to base idle. There was also a lag in response with quick throttle blips under load.
The TM-40 carb brought fast starts and rock steady idle to the table. I rode the bike 120 miles highway and city mix after installing and adjusting the carb idle mixture. The bike never stalled once and it has noticeable crisp throttle response through the entire throttle travel range. Now it starts right up cold or hot. I like the choke on my handle bar and used my stock chock set up. My bike is stock except for removing the snorkel from the intake box. I cut no holes in the intake box. I did put in the K&N filter that is recommended and the longer throttle cables that came in the kit. Before I installed the carb I moved the needle clip to the top most groove to lean out midrange and put in the 135 main jet. The carb shipped with a 145 main jet and the needle clip one notch down from the top. I left the 22.5 idle jet in and seems to be just fine for my application.
While the carb was off I put on the warp 9 starter end cab with the bearing vs the stock cap that has the bronze bushing in it. In my case I have gained about 8 MPG over the stock carb. I ride long country roads or freeway most of the time and I am easy on the throttle.
