Reply To: Hyosung GT125R – Oil question, oil coolers & overheating
GTRThe entire engine uses 1.5L of oil, see tutorial below on oil change guide https://hyoriders.club/forums/topic/change-oil-filter-hyosung-twins/
The good oil for summer is below (& HIGHLY recommended) and the service manual itself says use “premium” grade oil (not the cheapo) to extend engine life.
- Motul 71oo = 10w40 or 10w50
- Motul 300v = 10w40 or 10w50
- Silkolene Pro 4 = 10w40 or 10w50
- Silkolene Comp 4 = 10w40 or 10w50
These are also ESTER grade oils. I personally never use anything else on mine except these 2 brands and when i fix customer bikes, its what i use also.
If you have no local breaker near you that does Hyosungs , then you can always send an email , but below is 100000000% recommended and the bike will thank you.
- 250cc EFI Black Oil Cooler (forget grey ones) and becareful on ebay some sellers are dishonest and 50/50 chance half the coolers sold there come from bikes that blew their cranks and metal debris may still be floating inside the cooler, restricting flow or will be picked up by the drain plug magnets.
- Uprate your bike to have better jets (see tutorial here https://hyoriders.club/forums/topic/tutorial-hyosung-gv-gt-125-250-how-to-swap-carburetor-main-jets/)
- Improve your slide piston to be slightly more enriched (see tutorial here https://hyoriders.club/forums/topic/tutorial-carb-slide-needle-tuning-hyosung/)
- Go to our shop above ^ or ==menu== if on mobile phone, and get yourself stainless steel bolts and “possibly” fresh carb gasket kit if its an old carb that hasnt been touched for years, to avoid leaks, fuel zone is a critical area we don’t want to mess with it.
- If you can’t source main jets, send us an email , we usually keep stacks of them as we include them as part of K&N kits for the shop anyways.
I moved your topic to the technical section and edited the title for you.
Hope this info helps!
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