Stupid question on oil mix ratio (KDX newbie)

iamknowitall

Member
Aug 23, 2005
7
0
I know the manual calls for a 32:1 oil mix on my 1998 KDX. The bike is new to me and during the first ride, oil was covering the back fender, dripping on the rear caliper and generally a mess. It was like driving a mosquito fogger.
I am currently running some Bel Ray (I believe) full synthetic oil that came with the bike. I leaned it out to about 40:1, but am nervous about ruining the motor. Any suggestions?
My old bike (CR500) I ran for 15 years at 50:1 with golden spectro. Dont know why this wouldnt work for this bike.
Thanks, Adam
 

razrbakcrzy

Member
Aug 12, 2004
136
0
Not to be a butt or anything I just thought I should point out that what he is refering to is wrong. When you change from 32:1 to 40:1 to you do not lean the mixture you fattened it. You decrease the ratio of oil to fuel or increase the ratio of fuel to oil. example:40 parts fuel to 1 part of oil instead of 32 parts fuel to 1 part of oil. :) :ride:
 

iamknowitall

Member
Aug 23, 2005
7
0
Thanks for the response. I did not drop the needle yet. What position is recommended?
I have been wanting to get a few miles on it before changing anything. The previous owner worked at a bike shop and the bike already has a pipe, reeds, ported, etc. I was hoping it was somewhat dialed in.
 

lepper

Member
Mar 8, 2005
279
0
You don't jet with ratio.
Pick a ratio and jet it!
32:1 will give you more compression than 40:1 etc....
 

John Harris

Member
Apr 15, 2002
552
0
Most on here use 40 to 1 with all synthetic oil. Then set your needle clip in the next to the top position. If you have a 200 as opposed to a 220 and not heavily modified, then change the low speed jet to something like 42 and the main jet to 155 and fine tune from there. Cheers John
 

razrbakcrzy

Member
Aug 12, 2004
136
0



Think air/fuel mixture when you remove oil from the mix you put more fuel into the combustion chamber. The black soot on the plug is from unburned fuel not unburned oil. The oil is not all supposed to burn up or it would not be doing it's job. The main function of the oil is to lube the cylinder wall and rings to prevent wear.
 
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iamknowitall

Member
Aug 23, 2005
7
0
All,
Thanks for the great advice. I moved the needle clip as mentioned in the postings. I could not believe the difference in power and throttle response! It seems like 50 more cc's of motor. This thing screams now. Thanks!
 

FruDaddy

Member
Aug 21, 2005
2,854
0
lepper said:
32:1 will give you more compression than 40:1 etc....
I'm sorry, but I have to disagree. Compression has nothing to do with the fuel or oil used. Compression is the ratio of the difference between the volume of the cylinder when the piston is at bottom dead center, and the volume of the cylinder at top dead center.
 
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