Vortex ROK GP - changing Balance Shaft oil

Does anyone have a guide or video on how to change the oil in the Vortex ROK GP?

How frequently does the oil need to be changed?


It’s a 2 cycle engine, there is no oil in the engine. Only the oil that you mix with your fuel.

@Rapid1 That is incorrect. It does have gear oil to lubricate the balance shaft that should be changed regularly.

@Jgbedford, the drain plug will be on the side closest to the engine. Depending on how new your engine is, it’ll either have a clear sight glass in it or be just a regular solid aluminum plug. There’s also a 5mm bolt that’s lower on the engine that you can drain any extra oil out of if it all doesn’t come out of the main drain plug.

You can either fill it through the drain plug by tipping the motor on it’s side or through another plug that’s on the top of the case right next to the exhaust. I want to say it’s 100cc of 75w90 but I’m not 100% sure off the top of my head. I would change it at least after every race weekend. That way you can keep fresh oil in it and also keep track if you start seeing metal shavings.

Drain plug is red, fill plug is blue.


Sorry, thought he was talking about crankcase oil. It’s a question I often hear on 2 cycle engines.


Here is a link to our engine documents https://rokcupusa.com/rules/rok-cup-engines/, you will find the info you need under in the owners manual. As for how often, this is probably the least expansive maintenance item next to cleaning your engine, for me I would do it ever 2 track days, or every race weekend, for sure you can go longer but if nothing else you will make sure the fill levels are correct. Thanks for purchasing Vortex

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Thank you @CourterZT,

I see the plug, but can you identify the 5mm bolt you refer to?

Is it as simple as removing the plug, letting it drain, and refiilling through the fill plug after reinserting the drain plug? This can be done from a kart stand and does not require the motor to be removed from the chassis, right?

I appreciate the help!

Hi @Garett_Potter,

I appreciate the link to the manuals, thank you.

I see the type and amount of oil, I must be missing something - I don’t see where the manual specifically shows how to change the oil.


The bolt is almost directly below the drain plug, just slightly to the right.

Yep, it can be done on the kart it’s just a slight pain to get to. I normally remove the engine just to make it easier and give everything a thorough clean but it’s not necessary.

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