I own yuki SM 125 (QM125GY-2B with K157FMI engine)
stock engine wrecked and coudlnt get replacement in my country (Slovakia)
Fitted Suzuki GZ 125 Marauder engine inside..
rebuilded it with my mechanic
GZ 125 Marauder 2000 year bottom end (bought with 12000km on clock, spins easily, no rod play
used stock k157fmi cylinder and bored to 58.25 and used this piston
http://www.ebay.com/itm/KR-KOLBEN-KO...pVZ-33&vxp=mtr
bought suzuki gz 125 marauder head (2001 year) with 12mm sparkplug and 30/26 valves, valves has been grinded againist seat to make perfect seal/seat.. , piston rings were set and installed by mechanic.. and used rocker arms from k157fmi as they were in better shape than ones from used GZ head
bike had problem putting out more than 75KM/h!! (very low) i could jet it how i could want
replaced the stock filter with double foam filter, pitbike 38mm exhaust (loud as hell)
and installed LT230s camshaft used from ebay, bike did around 91-94km/h not tucked in and around 98km/h tucked,, and 105km/h with going behind car, tucked in , and backwind
now the cylinder is scratched after 8000km (double foam filter and took water in rain..) 9.5bar compression only opened throttle
going to rebuild it with big bore kit..
which one do you recommend?
could this one be used with domed top piston?
https://www.aliexpress.com/item/BIG-...999.301.1uT0vZ
my sparkplug is dr8ea
sprockets are 15/51 (used JT ones), from wemoto.com.. bike felt slow with 16/51 (this combo i used on old engine
used already once taobao (cssbuy agent) to order items from there, the right hand switch and clutch cable.
any ideas to make my bike go atleast like stock 100-105KM/h GPS? (using aftermarket speedo calibrated with GPS btw)

HEAD HAS NO SAI HOLE