Reply To: Carburetor GV 125 Year 2012
Hey Max,
Send me an email if you need Pilot Jets (Size 15 is oem for all 125 twins, but sometimes you will find 17.5 added by other owners and makes bike hard to start)
I will not ship your parts until you let me know first please.
I also have some “main jets” too.
For GV125 only this is the optimal settings:
Size 15 Pilot Jets = 2.5 turns out mixtures , both front and rear.
Size 90 & 92.5 is the max jetting and recommended.
Slide Needles = Factory is 3 grooves. 3rd groove towards pointy tip is good.
If you have 5 grooves = 3 to 5 groove towards the pointy tip is good, but check spark plugs and fine tune it. Maybe they like 3 or 4, because 5 is very rich.
Size 87.5 & 90 is OK too as long as bike uses standard factory exhaust and do no modify air filters (GV’s don’t like pod filters ever.)
Do not worry too much about air because GV250 also uses the same air filter and air box, it will flow enough air for 250 & 125cc. Just make sure filter is new because they get clogged faster than GT125s (GTs use 650cc air filter and are able to filter air for much longer before bike starts to feel like its on a leash & slower/sluggish). Around every 5K is a good time to check GV air filters to keep air flow optimal.
All GT125 have 87.5 and 90 because i work with a lot of hyosung bikes now ,everytime i do some upgrades ,i always find 87.5 front and 90 rear. 82.5 on a GV is too small but it is probably to slow it down (restriction?) but most motorcycle makers these days used to put smaller main jets to try meet EURO laws but there is a problem, they will be leaner in top gear (and thus bike gets much hotter), so its not good for piston rings in the long term.
I hope i have made sense , good spark plugs will help burn that extra fuel , but we will deal with electrics another time 😉 , lets fix the carb first.