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Mikuni TM40 on 650L

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Hello, just bought mikuni tm40 for my 650L. Has anyone tried one on this engine? I would be intrested in what jet sizes to start with! The bike has kn filter, bigger exhaust hotcams stage 1 and wiseco(compression promised 10,5:1 but I think more like 9:1).

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Hello, just bought mikuni tm40 for my 650L. Has anyone tried one on this engine? I would be intrested in what jet sizes to start with! The bike has kn filter, bigger exhaust hotcams stage 1 and wiseco(compression promised 10,5:1 but I think more like 9:1).

I have a TM40 for my XR600 that's set up for a Hardly Skirtster 1200. I have a Sudco manual with all sorts of jetting and schematics and whatnot. I'll send you a PM with whatever you need.

"O"

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I have a TM40 for my XR600 that's set up for a Hardly Skirtster 1200. I have a Sudco manual with all sorts of jetting and schematics and whatnot. I'll send you a PM with whatever you need.

"O"

What jets are you using then?

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I'm using a TM40 on my 650l. Overall I happy with it's performance, but I'm still fine tuning the jetting. I can't remember off hand what main I'm running but I have a #12.5 pilot installed and the clip on the third position from the top of the needle. It's still a bit rich on the idle circuit, but tolerable (worlds better than wen I got it). Like I said overall it runs well.

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What jets are you using then?

I have whatever it came with. The PO said:

Pilot: 20, 22.5, 25, 27.5

Main: 135, 137.5, 140

Air jet: 1.2, 1.3

Needle jet: Y-4

Needle: 9DHJ-1, 9DOJ-1, 9OJY-1

These are baselines. I'm not 100% sure it's accurate.

"O"

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I can tell you right now those supplied pilot jets are way too rich. I had to go all the way down to a 12.5 before it would idle right.

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I have 25 / 137,5 now and it's quite good. I dont have the accelerator pump used for now.. It's good to rev it up on first gear and put to second with full throttle. But if I dont rev it as much and put in second and full throttle it goes to the lean side. So, with the pump the high rpm accelerations suffer? Maby I just had it too much set..

How about you guys, how's your pump setup?

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I can tell you right now those supplied pilot jets are way too rich. I had to go all the way down to a 12.5 before it would idle right.

Are you using Mikunis own jets or somethin else? Those should be proper mikuni jet sizes.

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I have whatever it came with. The PO said:

Pilot: 20, 22.5, 25, 27.5

Main: 135, 137.5, 140

Air jet: 1.2, 1.3

Needle jet: Y-4

Needle: 9DHJ-1, 9DOJ-1, 9OJY-1

These are baselines. I'm not 100% sure it's accurate.

"O"

Good info! I'm going to order some air jets, needle jet and needles to try difrent setups. But install comes after the JE 11:1 piston next winter..

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