Technical Newbie questions regarding rotax FR125 pre evo

[PaddyM]

Hi guys.

Just purchased my first kart which is FA kart with rotax FR125 max engine. I’ve been trying to gather some information about maintenance and servicing of the engine but struggling to find much. As I have just purchased the kart I would like to change all fluids.

Am I correct in saying the only fluids in the rotax pre evo engine are gear oil and coolant along with 2 stroke oil to mix with petrol ?

From what I have read...

Gear oil is SA50W40.
Check oil every 2hrs and renew oil ever 50hrs.

Just need to find which coolant to use and pre mix oil with petrol and what ratio.

Oh and brake fluid is Dot 5 silicone fluid.

Any additional information is greatly appreciated.

Patrick

 

[Adam]

Hi guys.

Just purchased my first kart which is FA kart with rotax FR125 max engine. I’ve been trying to gather some information about maintenance and servicing of the engine but struggling to find much. As I have just purchased the kart I would like to change all fluids.

Am I correct in saying the only fluids in the rotax pre evo engine are gear oil and coolant along with 2 stroke oil to mix with petrol ?

From what I have read...

Gear oil is SA50W40.
Check oil every 2hrs and renew oil ever 50hrs.

Just need to find which coolant to use and pre mix oil with petrol and what ratio.

Oh and brake fluid is Dot 5 silicone fluid.

Any additional information is greatly appreciated.

Patrick

Hey welcome to the forum!

Gear oil you can grab here or from any other good online retailer:

https://www.ebay.co.uk/itm/Rotax-XP...331?hash=item1eca35d48b:g:eek:L4AAOSw1W9eTRca

BRP-RotaxREPAIR MANUAL: Check the oil level, top up if necessary - Every 2 hours of operation. Renew gear oil - Every 5 hours of operation. SAE Engine oil 15W-40. 50 ml (for plastic balance gears)100 ml (for steel balance gears).

I believe coolant is just deionised water and/or antifreeze mix:

A mixture of distilled water and aluminum-compatible antifreeze has to be used as coolant. Follow the antifreeze specifications to ensure protection against freezing up to a temperature of - 20 °C / -4 °F.

For brake fluid consult your chassis manufacture, but I think most are DOT5/5.1 including OTK/FA/Tony Kart/Exprit, Kosmic etc.

Pardon our interruption...

For fuel/oil mix. Rotax recomend their XPS stuff. I have been recomended to use Millers. Peoples choices vary. Millers seems good as it turns the fuel blue, so you know it's mixed.

Millers oil

Millers Oils KR 2T Motorsport 2 Stroke Kart Oil - 1 L - Rotax X30 Cadet Go Kart | eBay

KR 2T is a unique SAE 40 formulation, 2 stroke oil with a high performance/low ash profile. Specifically developed for high revving 2 stroke engines. Suitable for bikes, karts and all 2 strokes. Homologated for use in CIK-FIA competitions and events.

www.ebay.co.uk

Rotax recomend 3% 'running in' and 2% normal use. So for 2% it would be 200ml for 10L of fuel. 100ml for 5L of fuel. 50ml for 2.5L of fuel.

Full EVO manual can be found here for general references. Can't seem to find the pre evo pdf? I'll have a good look again tomorrow for you.

https://www.rotax-kart.com/upload/files/4729.pdf

 

[PaddyM]

Thank you Adam

 

[Adam]

Thank you Adam

No problems, you're welcome

 

[zfdesign]

Hey welcome to the forum!

Gear oil you can grab here or from any other good online retailer:

https://www.ebay.co.uk/itm/Rotax-XP...331?hash=item1eca35d48b:g:eek:L4AAOSw1W9eTRca

BRP-RotaxREPAIR MANUAL: Check the oil level, top up if necessary - Every 2 hours of operation. Renew gear oil - Every 5 hours of operation. SAE Engine oil 15W-40. 50 ml (for plastic balance gears)100 ml (for steel balance gears).

I believe coolant is just deionised water and/or antifreeze mix:



For brake fluid consult your chassis manufacture, but I think most are DOT5/5.1 including OTK/FA/Tony Kart/Exprit, Kosmic etc.

Pardon our interruption...

For fuel/oil mix. Rotax recomend their XPS stuff. I have been recomended to use Millers. Peoples choices vary. Millers seems good as it turns the fuel blue, so you know it's mixed.

Millers oil

Millers Oils KR 2T Motorsport 2 Stroke Kart Oil - 1 L - Rotax X30 Cadet Go Kart | eBay

KR 2T is a unique SAE 40 formulation, 2 stroke oil with a high performance/low ash profile. Specifically developed for high revving 2 stroke engines. Suitable for bikes, karts and all 2 strokes. Homologated for use in CIK-FIA competitions and events.

www.ebay.co.uk

Rotax recomend 3% 'running in' and 2% normal use. So for 2% it would be 200ml for 10L of fuel. 100ml for 5L of fuel. 50ml for 2.5L of fuel.

Full EVO manual can be found here for general references. Can't seem to find the pre evo pdf? I'll have a good look again tomorrow for you.

https://www.rotax-kart.com/upload/files/4729.pdf

Thai you very much for that @Adam I was in the same situation as PaddyM here. That definitely helps!

 

[Adam]

No worries @zfdesign ! To add to my previous post, I switched to this gear oil and coolant. Better quality and much cheaper! I changed the oil after every day of running.

Silkolene Gear Oil SRG 75 - Kart Parts

Silkolene Gear Oil SRG 75 | From Kart Parts the largest Kart part distributors in the UK with a massive stock range.

www.kartpartsuk.com

Silkolene Mag Cool Coolant - Kart Parts

Silkolene Mag Cool Coolant | From Kart Parts the largest Kart part distributors in the UK with a massive stock range.

www.kartpartsuk.com

These are also great for collecting any gear oil which want to escape out the vent hole. I drilled a small 2mm hole in the back at the top so it still breaths.

Pardon our interruption...

 

[zfdesign]

No worries @zfdesign ! To add to my previous post, I switched to this gear oil and coolant. Better quality and much cheaper! I changed the oil after every day of running.

View attachment 911

View attachment 912

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Silkolene Gear Oil SRG 75 - Kart Parts

Silkolene Gear Oil SRG 75 | From Kart Parts the largest Kart part distributors in the UK with a massive stock range.

www.kartpartsuk.com

Silkolene Mag Cool Coolant - Kart Parts

Silkolene Mag Cool Coolant | From Kart Parts the largest Kart part distributors in the UK with a massive stock range.

www.kartpartsuk.com

These are also great for collecting any gear oil which want to escape out the vent hole. I drilled a small 2mm hole in the back at the top so it still breaths.

Pardon our interruption...

More great stuff coming along. Thank you @Adam.

I wen on shopping spree last night after reading this tread. Including chain, sprocket, sparks, nuts, bolts etc. but I have hesitated a lot about the Rotax recommended Xeramic oil.

Isn't that mean to be better with added ceramic protection? At least on paper.

BTW the ROTAX docs link is no longer accessible. Here is what I found:

• 125 Senior Max Evo - https://www.rotax-kart.com/en/Products/MAX-Engines/1-125-Senior-MAX-evo ( 125 Senior MAX evo )
• 125 Junior Max Evo - https://www.rotax-kart.com/en/Products/MAX-Engines/5-125-JUNIOR-MAX-evo ( 125 JUNIOR MAX evo )

Documents available to view/download at the bottom right of each page

 

[Adam]

Great stuff @zfdesign ! In regards to the oil, are you referring to the 2 stroke oil or gear oil?

 

[zfdesign]

This is the one I was contemplating about
https://www.ebay.co.uk/itm/321821081473 ( XERAMIC KART GEAR OIL 1LT 5056020150527 | eBay )
Gear oil yes. Was also looking at the one you posted. Attracted by the price.

 

[Adam]

This is the one I was contemplating about
https://www.ebay.co.uk/itm/321821081473 ( XERAMIC KART GEAR OIL 1LT 5056020150527 | eBay )
Gear oil yes. Was also looking at the one you posted. Attracted by the price.

XERAMIC make alot of the Rotax/XPS stuff. You'll more than likely find it's the same stuff as the Rotax oil!

I've got loads of advice from various sources and most recommend the (Fuchs) Silkolene Gear Oil, it's well known for being a very high quality brand across the racing industry. Even heard of people using engines oil as gear oil.

You'll find most Kart shops, KKC, Kart Parts UK, Spellframe to name a few; won't even stock the XERAMIC or Rotax stuff.