Mikuni TM Believer

I received Mikuni 34mm TM carb today from Ebay and started configuring. The jetting that it came with was much too weak and a little heavy on the pilot. I have been running a 36mmVM with 40 pilot and 300 main.

It turns out that I had to pull the needle, needle jet and main from the round slide and it fit proper to the flatslide. Went from a 50 to a 45 pilot and that was it.

This is really close to cmessenk's setup in the end. The needle and needle jet made the difference.
Smooth idle, stump pulling low end, great mid response and a solid pull right past 6000g.
This 34mmcarb is an improvement all around from the 36mm roundslde.

Feels like the twin 32mm amals but without the crap.

The throttle cable worked from the 36mm and I had a 40mm rubber adaptor laying around for the new throat.
Total cost for me was $149.00

Hi pvisseriii,
Glad to hear that the TM is working for you, I have yet to finish installation of mine, although I did have it started very late last fall. The recommened needle for the VM and TM is 6DH3 and the needle jet (although a different style, #159 VM , #389 TM) is the same size P-0 or 1, 2, or 3. I am surprized at the #45 pilot jet works for you as mine seemed too rich with a #35. I am going to go down to a #27.5 to begin with. It has been mentioned before that the Mikuni kits tend to come on the rich side. I know "cmessenk" has a #35 pilot and he ended having to go up one heat range on his spark plugs in order to keep them from loading up.

GB

PS. Just re-read your post, I am surprized that you were able to swap the needle jet as the type 389 is somewhat longer, oh well, learn sommething new every day.

geo46er said:

Hi pvisseriii,
Glad to hear that the TM is working for you, I have yet to finish installation of mine, although I did have it started very late last fall. The recommened needle for the VM and TM is 6DH3 and the needle jet (although a different style, #159 VM , #389 TM) is the same size P-0 or 1, 2, or 3. I am surprized at the #45 pilot jet works for you as mine seemed too rich with a #35. I am going to go down to a #27.5 to begin with. It has been mentioned before that the Mikuni kits tend to come on the rich side. I know "cmessenk" has a #35 pilot and he ended having to go up one heat range on his spark plugs in order to keep them from loading up.

GB

PS. Just re-read your post, I am surprized that you were able to swap the needle jet as the type 389 is somewhat longer, oh well, learn sommething new every day.

Click to expand...

My 72 has a Combat head and a Big Bore exhaust system, hence the larger jetting.
I could not get it to run with the 6DH3 with the 389 needle jet. The way to fit the #159 type needle jet was to change the main jet ring (VM36/17) along with the needle(6DH3) and needle jet #159 Q2.
I believe that these three item could be a standard set up for Norton. The Main jet (280)and pilot jet (40) are good starting points for any particular need.