Needed changes for 50:1 to 40:1 mixture

G

G22inSC

Member

Jun 6, 2003

17

0

• Jul 22, 2004

• #1

I have a 97 KX 250 that the previous owner jetted for a 50:1 Mobil 1 MX2 premix. Am I wrong in wanting to change to a 40:1 mixture. I just feel 50:1 is cutting it too close. What changes need to be made to change to 40:1. Would I need minor adjustments or needle changes. I have no idea what needles are in the carb now, so any suggestions on good jetting specs would be greatly appreciated (for South Carolina in the summer). Thanks in advance.

 

MikeT

~SPONSOR~

Jan 17, 2001

4,095

11

• Jul 22, 2004

• #2

I'd switch it to 32:1 like it says in tha manual, then rejet from there. Run it a little with the new mix and see how it does then you'll know which way you need to go with the jetting.

 

E

Enduro_Nut

~SPONSOR~

Feb 7, 2002

1,155

0

• Jul 22, 2004

• #3

I run anywhere between 40:1 to 50:1, depends on my oil - full mineral oil, 40:1, semi sythetic 45:1, fullsynthetic 50:1. This advice was given to me by an ex-team green rider - he mentioned the manuals were written with 20 year info. regarding qaulity of oil -oils have changed ALOT in 20 years!! So, unless you want to spend extra $$$ - save it and go have fun!

 

a454elk

Mexicutioner

LIFETIME SPONSOR

Jun 5, 2001

7,529

18

• Jul 22, 2004

• #4

I agree with the Nut, hehe, I run golden spectro between 42 and 50:1 and it's fine. Tried at 32:1 like manual said and it spooged excessively. I stay around 40:1 now and jetted one leaner on the main and it's great.

 

E

Enduro_Nut

~SPONSOR~

Feb 7, 2002

1,155

0

• Jul 22, 2004

• #5

You calling me a "NUT"?? :laugh:

 

K

KX02

Member

Jan 19, 2004

781

0

• Jul 22, 2004

• #6

I couldn't imagine having to rejet to switch from 40 to 50 to 1. Think about it... 50:1 is 2.6 oz. into a gallon, 40:1 is 3.2oz. .6 oz into 128 oz of gas. You won't notice a difference in jettiing. Changes in temp affect jetting much more. I experimented from 32 to 50 to 1 with my KX and didn't notice any jetting related changes. Using less oil, did help clean up allot of spooge. I ended up sticking to 40:1 with Castrol TTS.