125cc X30 fuel mix and temperatures

Hello, I just purchased a new Birel with a 125cc X30 TaG engine. I have a few questions…
Best castor based oil to use?
Onces per gallon of 2 cycle oil?
Best coolant temperature in ⁰F?
Optimal EGT in ⁰F?
Should I use a little more oil during break-in?
What is the best way to break in the new engine, and for how long?
I’m more into longevity, and not so much maximum HP.
In the 90’s, I raced a Kali Kalifornia with a Parilla TT36, and the oil mix was 4oz. of Castrol castor R40, but I hear the X30 takes much more oil?
Thank you!

I use Elf HTX 909, it’s recommended by IAME. Not cheap but works well.

I use 8 Oz per gallon as recommended to me by both IAME and Fellow Karters

Like most Karts I like to be around 135 f on coolant temp and around 1175ish egt. Of course there are a lot of factors, I would highly recommend getting The IAME jetting app. It’s only 5 usd on the App Store and pays for itself after the first use.

Not a break in expert but I don’t see why using a little more oil would hurt.

Follow the manual for break in instructions. I really baby the engine in the beginning and then build up the revs. https://iameusawest.com/content/X30-Assembly-Manual.pdf

It’s page 26

Hope this helps!


Elf HTX 909 is a blend of castor and synthetic oils. It’s magic.
IAME and Elf recommend 4% oil, which is 5 oz per gallon.
Coolant temperature should be around 50 C (125 F).
Best EGT is 1000 F, higher in qualifying.
Same amount of oil for break-in and normal use.
To break in drive the engine normally but choke the airbox when you get to 10000 RPM for the first 5 minutes, 11000 RPM for the 2nd 5 minutes, and 12000 rpm for the third 5 minutes. Ideally you’d have short sessions on a quiet practice day to allow full cooling between these.
The question you didn’t ask is “what fuel should I use” and the answer is 93 octane pump gas, fresh that day, with any remaining mixture at the end of the day used either to clean parts or start the campfire.

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Thank you!
I was going to get 100 octane unleaded race fuel because our 93 octane has 10% ethanol, or does that not matter? Some say 6-8oz per gallon. Is that with a different 2 cycle oil?
5oz. per gallon should be safe?
Thanks for the information!

I’m slowly convincing people that ethanol is a beneficial and useful component of kart fuel. It’s good for both crankcase cooling and detonation prevention. I like Marathon/Speedway 10% ethanol 93, but if you prefer another brand it’ll probably be good too.

5 oz per gallon is what both IAME and Elf recommend. If I were stuck using a generic mineral 2-stroke oil I’d use 8 oz per gallon.

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Thank you!
One last questions. What tire pressures should I start out with?
It’s been a long time, but I think I used to run between 24 and 28 psi.

You’ll want a different tire gauge. With the MG Yellow tire we start at 10 PSI!

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Yes, it must have been much lower. I think I was thinking of the Porsche 914-6GT I used to race in the late 90’s early 2000’s.
I know on that car we were running 22psi fronts and 24-26psi rears.
The spec tires here in Jacksonville Florida are Vega Reds for the junior and cadet karts, and I currently have new Vega Blues on the Birel with the X30.
So typical tire pressures are from around 8-13 psi?

For break in follow the IAME user manual, just google x30 user manual you’ll find it.