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You'll get a lot of negative opinions here, but 60:1 is fine for a 2 stroke. There's a lot of threads here about how bad the KTM filter cage seals to the airbox, engines don't like dirt. Inspect the piston and cylinder wall for scoring when you tear it down.
60:1 is a "rich" fuel mixture (less oil / more fuel) Depending on the oil you used will play a part in your lubricating the bottom end.
Do you have any oil residue on you crank halves? (if you can spin the crank around) 32:1 will have a nice oil film on the crank halves.
If that was our bike it would be on a 32:1 mixture with Lucas Oil Semi Synthetic Pre Mix ...Period! And a 50/50 mix of race fuel & pump gas on a stock motor.
Like Jakes Dad said the bottom end likes oil and 32:1 will be plenty. The whole internals (crank, bearings, piston etc.) of the two stroke motor like oil. Oil is your friend...!
If you cooked the bottom end it's is due to too much heat.. either an air leak or lack of oil.
IMO.. if you sucked sand - dirt you top end is going to go out first.
Good luck!
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The Shop
JW... this should answer you question quickly...
Check out our 125 here.... http://www.vitalmx.com/forums/Race-Shop,42/05-KX125-with-37-2-Hours-on-…
Lucas Oil - It Works!
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No problem & good luck!
Did you ever live in Tucson, first name John? Just curious.....
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Now having said that I'm in a quandary right now trying to see if the flash points of premix make a big difference or not.
Lucas at 24 to 1 barely leaves enough residue for a Q-tip to clean up. And I've still had a crank failure with this combo, Lucas flashes around 180 deg. Jetting in the RM 150 (mod motor) was clip in 2nd from top main was 360 using a 9 plug. Always right on the edge of lean with about 15 degrees advanced timing. Cool good winter air here a 370 was good.
Now I'm trying Motul 800 2T because it has the highest flash point 485 deg, but way cooler cylinder temps by almost 20 degrees and less power. This was at 32 to 1 because I had a feeling with that high of flash point it would throw my existing combo off quite a bit. And a 10 plug to try and help temps also.
Anyway after getting Jake tuned in for a SX race this past weekend, I had to put a 9 back in it and go down to a 350 main for best performance (time I had). But plug was still fat looking with a light residue half way down the porcelain.
Now back last month when I sent the crank to TDC to get rebuilt I pretty much admitted that I screwed up and had too much advance in the motor and it probably pounded the bearings. There was only about 1/2" of heat showing around the big end not even enough to go up the rod beam. Brent at TDC said don't wash it, don't do anything just send it like it is. What he found was that the thrust washers were dry and that's when he told me to look in the crankcase for any premix residue.
So now after about 3 gallons of fuel through the motor I'm going to pull the cylinder and see how much residue is left over from the Motul after this weekends race. I loved the Lucas especially $30 a gallon off Amazon, why I didn't care even if I went down to 20 to 1 mix.
Saga continues............
FTR, I'm not saying anything is wrong with 32:1, but every motor I take apart at 32:1 is usually drowning in oil.
Glad to hear of your experience with the Motul SD, cause the Lucas left me wondering but man the motor ran great on that stuff.
Make sure your jetting is in accordance to the ratio you are running - testing.
20:1 = Larger Jets (richer).
50:1 = Smaller Jets (leaner).
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Here is some more info....
About Two Stroke Oils and Premixes
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Pit Row
Ok cool.
Had an old Mt Bike - race buddy named Jon Widows that liked Dirt bikes too. That's why I asked... JD381....
Cheers!
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Air was at 300 feet and I leaned the main down to a 350. I don't go to a 350 until the adjusted altitude is over 2000 feet. That was running the Lucas at 24:1 then. That's usually over 90 degrees here with over 70% humidity (normal July, Aug day here).
I did find out the Wossner rod was .010 shorter than the Hot Rods which was in it previously. So squish was at .042 nowhere near where I normally run it (.029 to .032). Luckily had a custom Cometic base gasket that now has it down to .034 so I'll live with that and it's at 55% of bore.
Don't like all the residue with only 3 gallons of fuel run through it Phillips 100LL. Keep in mind this kid runs this motor between 10 to 11,500 rpm almost all the time. Usually at 6 hours the plug has no residue and is coffee with cream color. Oh forgot changed from a 9 plug to a 10 here.
www.jalos.or.jp/onfile/pdf/2T_EV_LIST.pdf
Feb 1, 2014 - As for the on-file products which was not confirmed by the due date, the information would be publicized in the later occasions.
This is an updated list, this month, of 2 stroke oils and their classifications. The toughest spec is JASO FD. Does your oil cut the Mustard? I can't get the link to work!! But it is there. Any help?
FB, FC, and FD ratings specify the same level of lubrication. The main difference with FD is higher detergency, less smoke, and less carbon buildup (exhaust blockage).
http://jalos.or.jp/onfile/pdf/2T_EV0412.pdf
Did your piston look this bad trying to give out why mine has died
It had about 100 hours on it and still made good compression (170) so I pulled the top end and slapped some new rings on and scuffed the cylinder. Going to a .50 base gasket (from .65) and it pumped out 190-195 psi now.
Anyway, the cylinder, piston, head, pv stuff, etc... all looked mint. I didn't even mic anything. I know DV12 swears 50:1 is totally adequate and he and his dad know their two stroke stuff. I'm a believer.
I've also changed filters on a fairly regular basis (couple times each year, not fanatical) and kept the surrounding lip well greased. I did have an issue with the airbox boot actually being breached at the airbox - a freaking stick poked between them. On most other bikes that connection is bolted together, but not on KTM. Thank got I caught that early.
Also, the plastic cage is kind of challenging to get seated to the airbox. At least on mine, there are a couple tangs molded into the plastic cage that are supposed to help align the cage to the airbox. Those tangs should slip inside the boot, but you can totally mount it with those outside the boot which will create a killer gap between the filter.
On the air filter, I rode mine once with the stock setup and was way too paranoid about it sealing so I run a Loudmouthmx intake. The filters are rather small and get dirty quick but I put a clean filter on every time I ride anyhow.
Local pro's here sometimes run them at 25:1 at heavy WFO sand tracks.
The guy that bought my previous SX150 cooked his crank by running 50:1...
Post a reply to: Is 60:1 too rich for the 2014 KTM SX 250??