Bigger main jets upgrade size for gt125r 2015 This topic has 2 replies, 2 voices, and was last updated 6 years ago by Josh D. Viewing 1 reply thread Author Posts Dec 16, 2019 at 10:37 PM #3601 Josh D👤 Member Topics: 4Replies: 4 I have ordered an after market exhaust end can, and just need help finding what size main jets should i get. I am thinking i would need front:90 rear:92.5 main jets. mine has the stock ones which are front:87.5 and rear:90. Dec 16, 2019 at 10:47 PM #3602 ♠️ M77👑 Admin Topics: 40Replies: 2,986Country: UKBike Model: GT Moved to Technical. Yes you are correct for the 125 it is 90 front and 92.5 rear as an upgrade.👍 More about that here [Tutorial] How to swap Carb Main Jets – Hyosung GV & GT 125/250 Dec 19, 2019 at 11:36 PM #3617 Josh D👤 Member🖊 Topic Author Topics: 4Replies: 4 cheers, thank you. Author Posts Viewing 1 reply thread You must be logged in to reply to this topic. SHARE THIS Share on WhatsApp (Opens in new window) WhatsApp Share on Telegram (Opens in new window) Telegram Share on X (Opens in new window) X More Share on Facebook (Opens in new window) Facebook Share on Bluesky (Opens in new window) Bluesky