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Cr 250 2006 baseline jetting (tmx)

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Hi,

I will change my carb for an airstryker next winter but for now I will settle with the tmx and trying to make it work :) I have a stock 2006 with boyesen rad valve and a fresh top end. I ride mx at 0-800 elevation.

If someone have guideline for the jetting it would be appreciate,

Thanks! :)

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Hi,

I will change my carb for an airstryker next winter but for now I will settle with the tmx and trying to make it work :) I have a stock 2006 with boyesen rad valve and a fresh top end. I ride mx at 0-800 elevation.

If someone have guideline for the jetting it would be appreciate,

Thanks! :)

 

Pro circuit has jetting baselines here is a link:

 

https://www.procircuit.com/jettingspecs2.htm

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THat pro circuit chart isn't going to work b/c The boyesen rad valve will require leaner jetting.

I used to own one for a different bike, and I remember reading this lean jetting requirement in the instructions sheet.

 

In addition, the stock TMX jetting has been shown to be too rich, producing excessive spooge. You can move the needle clip around all you want, but

it won't  clean up the excessive spooge.

You ought to replace that stock needle w/ a leaner needle, especially so with the Rad valve in use.

 

So you have two opposing problems that imo will not be fixed w/ your stock jetting parts that came inside the TMX.

You will need to buy extra mains, pilots, and needles that are slanted in the leaner direction, and

will have to go through 3-5 jetting passes before you get it in the ball park. if you can't commit to this amount of work, or don't know

enough about jetting to do so, then

you should just pay someone to get it done for you.

And, you can also scratch off the popular JD jetting kit for the TMX carb b/c it was only developed for the stock 8 petal air valve, not for the Boyesen.

 

If it were me, I'd order 380, 390, 400 size mains, 32.5, 35, 37.5,  pilot, and two leaner Honda TMX needles.

Here's a honda parts nomenclature list I plucked out of rocky mountain mc dot com

 

  99143-KZ4-3800 JET, MAIN (#380) | (Optional). $8.87 $7.81 5 In-Stockgreen-check.png     99143-KZ4-3900 JET, MAIN (#390) | (Optional). $8.87 $7.81 4 In-Stockgreen-check.png     99143-KZ4-4000 JET, MAIN (#400) | (Optional). $8.87 $7.81 6 In-Stock

 

43 99133-KZ3-0320 JET, SLOW (#32.5) | (Optional). $9.45 $8.32 2 In-Stockgreen-check.png   43 99133-KZ3-0350 JET, SLOW (#35) | (Optional). $8.98 $7.90 3 In-Stockgreen-check.png   43 99133-KZ3-0370 JET, SLOW (#37.5) | (Optional). $9.45 $8.32 2 In-Stockgreen-check.png

 

 

 

  16201-KSR-A02 NEEDLE SET, JET (6DGY26-66) | (Optional). $14.40 $12.67 1 In-Stockgreen-check.png     16202-KSR-A02 NEEDLE SET, JET (6DGY26-67) | (Optional).

Note: The last two digits in the Mikuni PN, -66, denotes the straight section's diameter. The higher the last two numbers, the larger the diameter, the leaner the needle is.

 

Once you have all these jetting parts in hand, then you can proceed quite easily w/ jetting it precisely for the Rad valve and to your riding conditions.

Also, remember to match your premix's flash point value to your style of riding. If you ride tight slow woods, you want a premix w/ low flashpoint. If you ride fast, wide open tracks or desert, you want  a high flashpoint premix.

Motorex premix has a low flashpoint, whereas Motul 800 has high flashpoint. There's a plethora more 2 st oil selection, but those two are pretty common to find at most m/c stores.

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Also, this is a good time to establish your premix ratio, and then jet the bike for that ratio.

I use 32:1 if I mostly ride wide open, fast areas like desert and motocross.

I use 50:1 if I ride mostly tight woods.

 

But most of the time, I just go w/ 40:1, bc/ it's midway between those two regions.

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THat pro circuit chart isn't going to work b/c The boyesen rad valve will require leaner jetting.

I used to own one for a different bike, and I remember reading this lean jetting requirement in the instructions sheet.

 

In addition, the stock TMX jetting has been shown to be too rich, producing excessive spooge. You can move the needle clip around all you want, but

it won't  clean up the excessive spooge.

You ought to replace that stock needle w/ a leaner needle, especially so with the Rad valve in use.

 

So you have two opposing problems that imo will not be fixed w/ your stock jetting parts that came inside the TMX.

You will need to buy extra mains, pilots, and needles that are slanted in the leaner direction, and

will have to go through 3-5 jetting passes before you get it in the ball park. if you can't commit to this amount of work, or don't know

enough about jetting to do so, then

you should just pay someone to get it done for you.

And, you can also scratch off the popular JD jetting kit for the TMX carb b/c it was only developed for the stock 8 petal air valve, not for the Boyesen.

 

If it were me, I'd order 380, 390, 400 size mains, 32.5, 35, 37.5,  pilot, and two leaner Honda TMX needles.

Here's a honda parts nomenclature list I plucked out of rocky mountain mc dot com

 

  99143-KZ4-3800 JET, MAIN (#380) | (Optional). $8.87 $7.81 5 In-Stockgreen-check.png     99143-KZ4-3900 JET, MAIN (#390) | (Optional). $8.87 $7.81 4 In-Stockgreen-check.png     99143-KZ4-4000 JET, MAIN (#400) | (Optional). $8.87 $7.81 6 In-Stock

 

43 99133-KZ3-0320 JET, SLOW (#32.5) | (Optional). $9.45 $8.32 2 In-Stockgreen-check.png   43 99133-KZ3-0350 JET, SLOW (#35) | (Optional). $8.98 $7.90 3 In-Stockgreen-check.png   43 99133-KZ3-0370 JET, SLOW (#37.5) | (Optional). $9.45 $8.32 2 In-Stockgreen-check.png

 

 

 

  16201-KSR-A02 NEEDLE SET, JET (6DGY26-66) | (Optional). $14.40 $12.67 1 In-Stockgreen-check.png     16202-KSR-A02 NEEDLE SET, JET (6DGY26-67) | (Optional).

Note: The last two digits in the Mikuni PN, -66, denotes the straight section's diameter. The higher the last two numbers, the larger the diameter, the leaner the needle is.

 

Once you have all these jetting parts in hand, then you can proceed quite easily w/ jetting it precisely for the Rad valve and to your riding conditions.

Also, remember to match your premix's flash point value to your style of riding. If you ride tight slow woods, you want a premix w/ low flashpoint. If you ride fast, wide open tracks or desert, you want  a high flashpoint premix.

Motorex premix has a low flashpoint, whereas Motul 800 has high flashpoint. There's a plethora more 2 st oil selection, but those two are pretty common to find at most m/c stores.

Good info. Thanks for posting for others to see... 

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Kiss off H4L, your obsession with me is proving how big of an ass you are.  And speaking of inaccurate/misleading information, I want to see the dyno graphs of your "55 hp" CR250, not just what pro circuit told you it "should have". 

Edited by frdbtr

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Yess I Know it was too rich with the stock jets I had, after looking at the pc chart there wasn't a lot of difference with stock so I will buy 3-4 differents main pilot needle to test n tune, I have no problem with jetting but it's fun to have an approximation when possible so you don,t mess with the carb too much

Thank you for the help I appreciate :) and sorry my english isn't perfect :)

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Kiss off H4L, your obsession with me is proving how big of an ass you are.  And speaking of inaccurate/misleading information, I want to see the dyno graphs of your "55 hp" CR250, not just what pro circuit told you it "should have". 

:thinking:

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THat pro circuit chart isn't going to work b/c The boyesen rad valve will require leaner jetting.

I used to own one for a different bike, and I remember reading this lean jetting requirement in the instructions sheet.

 

In addition, the stock TMX jetting has been shown to be too rich, producing excessive spooge. You can move the needle clip around all you want, but

it won't  clean up the excessive spooge.

You ought to replace that stock needle w/ a leaner needle, especially so with the Rad valve in use.

 

So you have two opposing problems that imo will not be fixed w/ your stock jetting parts that came inside the TMX.

You will need to buy extra mains, pilots, and needles that are slanted in the leaner direction, and

will have to go through 3-5 jetting passes before you get it in the ball park. if you can't commit to this amount of work, or don't know

enough about jetting to do so, then

you should just pay someone to get it done for you.

And, you can also scratch off the popular JD jetting kit for the TMX carb b/c it was only developed for the stock 8 petal air valve, not for the Boyesen.

 

If it were me, I'd order 380, 390, 400 size mains, 32.5, 35, 37.5,  pilot, and two leaner Honda TMX needles.

Here's a honda parts nomenclature list I plucked out of rocky mountain mc dot com

 

  99143-KZ4-3800 JET, MAIN (#380) | (Optional). $8.87 $7.81 5 In-Stockgreen-check.png     99143-KZ4-3900 JET, MAIN (#390) | (Optional). $8.87 $7.81 4 In-Stockgreen-check.png     99143-KZ4-4000 JET, MAIN (#400) | (Optional). $8.87 $7.81 6 In-Stock

 

43 99133-KZ3-0320 JET, SLOW (#32.5) | (Optional). $9.45 $8.32 2 In-Stockgreen-check.png   43 99133-KZ3-0350 JET, SLOW (#35) | (Optional). $8.98 $7.90 3 In-Stockgreen-check.png   43 99133-KZ3-0370 JET, SLOW (#37.5) | (Optional). $9.45 $8.32 2 In-Stockgreen-check.png

 

 

 

  16201-KSR-A02 NEEDLE SET, JET (6DGY26-66) | (Optional). $14.40 $12.67 1 In-Stockgreen-check.png     16202-KSR-A02 NEEDLE SET, JET (6DGY26-67) | (Optional).

Note: The last two digits in the Mikuni PN, -66, denotes the straight section's diameter. The higher the last two numbers, the larger the diameter, the leaner the needle is.

 

Once you have all these jetting parts in hand, then you can proceed quite easily w/ jetting it precisely for the Rad valve and to your riding conditions.

Also, remember to match your premix's flash point value to your style of riding. If you ride tight slow woods, you want a premix w/ low flashpoint. If you ride fast, wide open tracks or desert, you want  a high flashpoint premix.

Motorex premix has a low flashpoint, whereas Motul 800 has high flashpoint. There's a plethora more 2 st oil selection, but those two are pretty common to find at most m/c stores.

Perfect.  By the time you sort through all this minusha, should've gotten a pwk already.  LOL.

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Kiss off H4L, your obsession with me is proving how big of an ass you are.  And speaking of inaccurate/misleading information, I want to see the dyno graphs of your "55 hp" CR250, not just what pro circuit told you it "should have". 

What a squid..  You have some serious issues & should get some professional help. 

 

Once again - If you DON'T want a response DON'T communicate in any way shape or form.   You keep making an ass out of your self & can't help your self....  

I have found Pro Circuits jetting to be fairly close for my 03 250. 

In my experience PC has decent  jetting specs on the 02-03 non tps mikuni vs. the 05-07 tps version.

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