Hi all-
I recently purchased a Mikuni TM36-68 to put on Bill Blue's 351 big bore on an '07 KLX250. I've gotten some good ideas about jetting for this set-up (thanks Mustang, Mooredan, boxermachine), however I have a question regarding the main air jet in this carb. After briefly inspecting the carb out of the box, I noticed that the main air jet hole had nothing in it. After looking at an exploded view of the specs, it shows a plug inserted into the hole (part #BS30/97 #0.0).

Should the main air jet be plugged, or should I be putting some sort of flow through there? Just kind of stumped why this would be plugged up. If it's not needed and is plugged, why is it even there? Thanks in advance for any light shed!

Also, anyone reading this who has a big bore with this carb, just curious if anyone has discovered anything radically better than what was last posted by Mustang about a year ago:

Main Jet: 130
Pilot Jet: 17.5
Needle Jet: P-4
Needle: 9EBY1-50
Needle Clip: 3rd slot from top (middle position)
Fuel/Air Screw: 2 turns out
A/P Pump Timing: Starts at 1/8 throttle and stops at 3/4 throttle
A/P Squirter: Pointed directly at the needle (fuel should splash off of the needle)
K&N Air Filter with lid off
Full Exhaust

 

Don't know about the air jet hole.
This is what I have in my 36mm. Runs clean.

Main Jet 130
Pilot jet 15
Needle Jet 568-P8
Needle 9DZK6-50
Clip in middle slot

Ride on
Brewster

 

Thanks for the input Brew. What displacement are you running it on?

 

300cc, Stroker header with stock unplugged muffler.

To get good response, both the start of the a/p and the duration have to be adjusted.

Ride on
Brewster

 

Good question! And I have no idea what the answer is. According to Sudco, the TM36-68 should have no main air jet (open hole), while the HS40 should have its main air jet plugged. Mine has an open hole and no plug, but the hole is threaded, as if to accept a jet. Go figure.

 

Thanks for the response Mike! I'm good just knowing how you have yours running. I'm ordering jets and thought I would buy a plug since mine didn't come with one and I saw that the HS40 did. I figured they forgot it in my TM36. But if yours is open also, case closed!

Also, thanks for the info on the ANF. We used your advice to plan our trip only to find out that pretty much all the trails are closed until Memorial weekend (excessive rains?), and everybody took vacation for next week. So, we're heading to the Hatfield-McCoy trails for a week. Looks like a blast! Anyway though, thanks again for everything Mike!