All Pit bikes carry a copy of the Honda CT110 Monkey bike engine that Honda released in the 1950s.
The Chinese took this technology and bought the patent for the engine. Basically, the 125cc is a supped up version of the Honda CT110. There, they showed the same engine casings and the engine casing that they fitted 54mm piston and extended stroke.
125cc The engines are now stable and reliable but there was a nightmare in which the first release on the market.
Some Common 125cc Problems (When First Edition)
o The clutches were not strong enough to handle the extra power 125cc had.
o Gearbox was weak and you would usually lose 2 gears. Again, the effect increases without upgrading the rest of the engine.
o Over heating the engine. The pistons used were just a garden range. The aluminum should stress at high temperatures and turn and drain the rings. It would melt and the plunger in the dish. Ouch Not good.
o The inner seals on the side of the gear and clutch tires would burst and leak the gearbox oil because the pressurizing valve would get stuck between the frame and the engine in assembly, which did not allow the engine pressure to escape.
o Crucial Engine internal parts such as piston, rings, bearings heated by inexpensive raw materials which resulted in poor quality product.
The best 125cc engine and most common and reliable on the market is the Li fan motor. A near 2nd comes Zongshen, Then You car. Jailing 125cc is the best racing engine built for the 125cc class but it is much more expensive.
Some 5 years later, the 125cc engines are now very reliable and 99.5% of all problems have been eliminated. It is only possible to show that Japanese Japanese technology was far advanced for its time.