Reply To: Midrange lack of power GT125R
Front Plug is oily on the threads , i would be looking to check:
- Have the valve stem seals ever been changed ? *(if the valve seal is worn out, it could drip oil in the combustion chamber during revving up = bit of smoke puff on exhaust, it would smell a bit oily, but its a faint hint!) * Check history of that engine if the valves ever got service at all.
Try this bottle “ONLY!” (ignore everything else!)
As it states it is safe for “carbs” and “motorcycles” , Wynns is a trusted brand
https://www.halfords.com/motoring/engine-oils-and-fluids/fuel-and-oil-additives/wynns-lead-substitute-with-fuel-stabiliser-118855.htmlFollow instructions on the box, then generally ride with a half tank of E5 with that product (mix the correct amount! = As half a tank is about 8L ish of E5 fuel) - Check oil level , every 20-50 miles and see if its going down
- Check oil level as above ^ but check if its getting dark & darker quickly (if it was having oil change today)
- Use strictly Motul 7100 – most recommended oil for the 125 Hyosungs and its a high heat oil due to fact our 125s have small oil coolers
- Invest in a Gt250 EFi oil cooler. It will thank you a lot. Do not bother getting chinese coolers , you want the oil pump happy. I’d trust Korea on their coolers this time!
If i am wrong ? Is that wet plug “FUEL” ? — If its wet fuel , then ignore what i said above ^
If it is WET FUEL
- Service the carb and yes check your floats
- Replace the floats , float seats , float needles – So the bike isn’t jamming (while riding) or flooding the cylinder (while riding or overnight standing as it drips out of the carb in to the manifolds then piston chambers)
- Open the “OIL FILLER” cap –> Sniff hard for fuel , if there is fuel smell that is strong , don’t ride it and change the oil.
- Replace the filter , i would mandate this tbh.
While riding === I need to ask?
- Do you hear “popping sounds” in the airbox as you rev up while riding ?
- Does it pull back hard, then slingshot forward ?
- Or does it bog down while riding as revs go up , but only “smooth ride” is during very low speeds ?
I want to ask more but let’s address the top first so we build a proper picture
Let us know everything I just said.
PS. Glad the caps work for you , that’s why we all use them 😉 – Gotta love NGK caps!