Stupid question on oil mix ratio (KDX newbie)

[iamknowitall]

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

 

[lee42lee]

You should be fine at 40:1 that is what I use in my 2001 KDX 220.

 

[G. Gearloose]

. .

 

[razrbakcrzy]

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]

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.

 

[Kwakasaki]

Then more fuel to one part oil would be leaning the oil mixture, correct?

 

[lepper]

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]

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]

Have you been to CDave's site?

The basic information you need to get started on jetting is there. It is linked in the 'Every kdx rider should read...' link stickied to the top of this forum.

Yes, a 9 is too cold. Note that changing premix from 32:1 to 40:1 will make the problem worse..you are making the air/fuel mixture more rich with that change. Plugs are fouled by a too rich an air/fuel mixture, NOT too much oil (within reason of course...and many other things being 'good').
A 7 is close to too hot. Well, depending on how you ride and how you're jetted. Making jetting changes while using an ill-chosen heat range plug is a recipe for disaster. Changing plug heat ranges to make up for improper jetting doesn't accomplish anything.

The kdx 2-hunny will run forever on an '8' plug if it is jetted 1/2 fast right. That jetting is not only bike-dependent, but rider-dependent, too. What works well for rider 1 may not work well at all for rider 2. Let alone elevation, humidity and temperature differences from place to place.

Bookmark this:

http://www.buykawasaki.com/site/VIVehicleInformation/VIChooseVehicle.asp?intCatalogID=2&intParts=1

Take note this is NOT the 'front page' of the site..but the info lookup page per make/model/year.

From this site you can find that the stock jetting for your bike is 48/150.

re: 'My jet sizes are as follows 58, 155, 172'

No they aren't. You don't have three removeable jets...only two..pilot and main. In any case, if any combination of those jets are in your bike, it is so far off you can't even SEE your bike from here (probably due to all the smokin')!!!


re: Is this ok for 5k+el.

What Gearloose said.


A premix ratio change to 40:1 from 32:1 is making your air/fuel mixture more rich, making an already bad situation worse.
In the 'Every KDX rider should read this...' stickied to the top of this forum you (and everyone else) will find a link to Canadian Dave's website. I would suggest that every KDX rider read it. ...for all of you that haven't asked, consider yourselves to have received anyway.

re: Can a bad crank seal cause this problem (smokin').

Yes.


A change in plug heat range to address a poorly jetted bike is for sure a misstep in the wrong direction.


A 'needle jet' and a 'jet needle' are two different things. A jet needle fits inside the needle jet. The jet needle sits inside the throttle valve. Most Keihin carb needle jets are not replaceable through average means. Keihin needle jets are rarely changed/tuned for that reason.

There is an altitude jetting compensation chart on CDave's site.

Cheers!

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.

 

[iamknowitall]

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]

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.