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2/8/2024
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Runcorn, GB
Hi guys. I have just bought a 2023 ktm 250sx, it’s always been run on shell vpower fuel (99ron) with 40:1 Castrol power 1 racing 2t, I feel it’s abit smokey. And would like to switch to same fuel but with a 50:1 motorex cross power 2t. Now would I need to have it mapped to suit this new mixture? And would I need to do any adjustments?
the Castrol power 1 racing on bottle says 50:1 and the guy has always used this at 40:1 so 10 down.
the motorex cross power 2t says 60:1 so if I use this at 50:1 that’s 10 down like the 1 above.
i no ktm state 60:1 but I don’t want to make a big jump like that.
thanks
The oil manufacturers suggest the ratio based on viscosity and type of oil (mineral, semi-synthetic or full synthetic). Follow the Motorex suggestion of 60:1.
Smoke is all about engine tuning, if you don’t clear it out well it’s never gonna stop smoking, even my old ktm is a little Smokey before I clear it out with PERFECt jetting
-spy
Can’t do any jetting on this mate it’s fuel injected
Well damn, go to 60:1 if it’s STILL to smoky for your opinion, go get the ecu flashed and mapped, and then if it’s still too smoky, put some exhaust packing in.
-spy
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If you're riding motocross, you usually generate a lot of heat and there wont be any 'oil smoke' from your 2-stroke once it's done a lap and is at operating temperature. That applies from 30:1 up to 100:1. All of those oils you mentioned 'burn' easily and won't smoke.
Any smoke you see at the exhaust is 99% unburnt fuel.
Less oil is going to make the bike run a bit richer. Might be best to stay 40:1 unless you can get a remap to lean it out.
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