Reply To: 20 year old GV 250
MPG wise i would say the 125 will have a slighly better MPG than a carby 250 does due fact less piston size , and lesser jetting but still lives high rpm life>
ie. 10k revs in 3rd gear for 40mph in 125cc, the 250 would achieve that in less reves, just an example (not accurate, just a guess)
Fortunately it’s easier to change gearng of the 125 in to cruise mode to use less revs and a bit less fuel , by upgrading to a 520 chain and sprocket set. The slim 428 chains aren’t worth wasting too much money on a heavy bike that will stretch and vtwins by nature start their power at lower revs than a big cc inline 4 bike.
Go get the 125 🙂 , and ofcourse ignore whatever the previous owner did to , always assume its 0 miles (no matter how old it is) and be ready to give if a fresh overhaul of servicing from the get go , usual like tyres brakes filters , fuel lines, suspension checks and all that stuff. if you dare , stripe it down to bare frame while leaving engine inside and just clean up the parts with a nice drag and wipe down the frame from any mud, road traffic film and or oil spills from oil changes or chain grease gunked up inside sprocket cover with a good de-greaser