Pre mix

[pkbarbiedoll]

I used Castrol's 2-stroke premix all last year, mixed at 44:1.. my bike never smoked.  Yesterday though I drained everything out and filled up with 927 castor mixed at 44:1, and now my bike smokes.  rings don't go bad after 30 minutes, so the change in oil is what is causing the extra smoke.    my question is what should I mix the castor at so my bike won't smoke so much?

[eprovenzano]

The best thing you can do, it to select a quality oil, select your premix level, jet as needed, and stick with it.  I've recently switched from Yamalube to Amsoil.  It required jetting adjustments, but I happier with the change.  Like you, I used Yamalube for years, with no problems, I just wanted to got to synthetic oil.  I stayed with my 40-1 ratio, but I too had a tab bit too much smoke.  I ran that way for a couple of rides, no fouled plugs, just too much smoke for me.  So I adjusted the jetting to reduce the smoke, and all is well.

I'd run as is for a few rides, if it keeps up, adjust jetting.

[kx_rider53]

He wins ^^. Its is all about jetting. Pick an oil and ratio and jet for it.

[Wizzy214]

yep figure out your jetting.

i use mobile 1 racing 2t @ 32:1 - 40:1  with little to no smoke after warmed up. in my 99 250

[Utah]

I hear a lot of good things about klotz. Think I'll give it a try this season. Even supposed to smell pretty good!

[pkbarbiedoll]

That is why I changed to castor oil, I miss the smell with all the thumpers. 

thanks for your suggestions.. i'll ride a few more times and then take a look at jetting. 

[Utah]

I posted similar to this by mistake in KX5 forum:

Try again; for pre-mix ratio, what is best for mixture of low speed trail "bog" and high speed desert runs? I expect to run a good quality synthetic oil like klotz. Want to run as lean as possible without danger of seize. Check out the KX5 forum for similar discussion "Pre-Mix". Some report running 100:1 as "shear" value of synthetics is so high that oil molecules dont break down as fast as the old school oils. Anybody running really lean mix with the KX250?

[The Flyin Hawaiian]

I run a 50:1 mix in my 04 250. I use Motul 800.

[fastducky]

I run 40:1 using mobil 1 racing t2 oil. I did install a "JD" jet kit when i bought my bike. No smoke and i haven't change a plug in a year.

[pkbarbiedoll]

Does my 99 kx use the same jets as the 97 model?  Anyone know what the stock main and pilot jets are?

[redlined_KX500]

 Stock specs are the same from 1990-1999 per Clymer. 2000 on only slight changes.
 
 168 main
 N82/M needle, clip in 3rd slot
 60 pilot
 air screw at 1.5 turns out
 float height  15-17mm

I have a 99 K5. I mix mobil1 2T with straight C12 at 50:1 with 165 main main, 55 pilot, air srew at 2 turns.  Only mods are PC works, reed spacer, V-force and Eric Gorr ported cylinder.  Bike is slightly rich until it hits operating temp then it runs like a striped ape.

Oh yeah I run the bike in an average of 700 foot elevation range

[pkbarbiedoll]

Mine had a 158 main in it so I'm bumping that down to 155.   Here's hoping my bike's drooling problem stops!

[Hammer 4]

Hmmm, my 99 kx 250 came with a 158 main 52 slow jet. I rejetted using a 155 main, 45 slow jet, and air screw turned out 1 1/2 turns, my plug looks really good. Also I mix Spectro full synth at 52:1 using Chevron 91 octane. I use a uni air filter, have a FMF fatty pipe.

[pkbarbiedoll]

I raced mine today with 155 main and 42 pilot.. better but still a little drool showing near the pipe/silencer connection. 

[Hammer 4]

I raced mine today with 155 main and 42 pilot.. better but still a little drool showing near the pipe/silencer connection. 

What elevation are you at..?  Have you repacked the silencer yet.?