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Joined
7/19/2012
Location
Trussville, AL
US
Edited Date/Time
2/7/2016 11:18am
So the manual for my new KTM 150 SX is no where near as detailed as my Yamaha manual is and there is no recommended break-in fuel ratio. The yamaha manual states 15:1 for break in, should I use the same for the KTM? Also 32:1 is perfect in my 125 for regular riding, I noticed the KTM manual says 40:1 which makes me nervous as that seems lean. Thoughts and advice and thanks in advance!
The 150SX manual states even as high as 60:1 is good for 95 octane fuel so I wouldn't be too concerned with 40:1 if I were you if you didn't do anything crazy with the jetting.
With that said ...... I have used Golden Spectro @ 50:1 for 30 years and have NEVER had a motor blow up.
I think this guy is giving you the right advice, but to make it more clear. 32:1 oil ratio will yield a LEANER fuel mixture than 40:1. More oil=less fuel
The Shop
Go ride.
Oils I use are: Maxima K2 & Motul 800.
You say it will be "way more expensive to run 32:1 over 40:1".
118cc (32:1) - 95cc(40:1) = 23cc per gallon difference
23cc of oil x 50 gallons of fuel = 1150cc aka just over a liter, (or quart 946cc) and I doubt many people burn 50 gallons of fuel per year...
The big 5 and have never had a problem running 50:1. Now will a bike run better with more oil? Probably but it has to be jetted for it. With stock jetting and using a high quality synthetic premix it is not necessary to run 32:1. The reason I said more expensive is if you are running motorex at say $15 a bottle at 32:1 vs 50:1 you without a doubt will spend more money. May not be a lot of
Money to you but if it's a kid running around on a 125 that's a lot! When I was a kid I would ride from sun up to sun down and if I was paying $15-17 for premix it would get expensive pretty quick. But my main point was if ktm says 50:1 and the oil says 50:1 and the bike is jetted for 50:1 there won't be a problem.
Jetting can compensate for pretty much whatever ratio you want to run. However, since the OP has a new KTM 150 and is most likely starting with stock jetting, it is set for optimum oil ratio of 40:1 to 60:1; and I doubt that KTM has a vested incterest setting up their machines to run at lower power.
My old man also raced for Arctic Cat in the 70's for oval track sleds. They logged many hours on a dyno with factory engineers...and they always made more power with more oil.
High stress/high load two strokes like oil, I do not understand the reasoning for running anything leaner than 40:1
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I'm sorry if I am missing something, but those stories have failed to convince me. I think the best option here is to stick to the manufacturer's recommendations since their chief interests are performance and reliability.
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