Please note: These pages are part of my RS 125 Workshop Page on my web blog and they are not related to the manufacturer Aprilia/Piaggio. These are self-written repair instructions, hints, tips and tricks for the old Aprilia RS 125 with two-stroke engine until year 2012. This blog is operated by a private individual without commercial background and without any benefits. There is absolutely no warranty. Any liability for any kind of damage that may be related to information from this website is totally denied. Use at your own risk.
Pressing the engine start button and immediately checking how the engine responds to throttle changes on high rpm – that’s exactly how to break the engine and ensure a small lifetime. The worst mistake you can actually make is to turn up the engine rpm right after the start. Unfortunately, it is still quite common.
Warming up is extremely important to ensure a long lasting engine. If the engine is cold, the preloads of bearing arrangements, the piston clearance, tilting clearance and also the viscosity of the oil are not in proper ranges, therefore the engine wear is extremely high when the engine is cold and under high load.
After starting your engine, you should never turn the throttle on maximum. Just start to drive comfortably (try to stick to “if you drive slowly you will be seen longer”). The engine should neither be used with full power in the respective rpm nor should you drive in high rpm. You can drive with daily traffic below 7.000 rpm. Usually it takes about 3 to 4 km to warm up the engine.
You will find reports from people about warming up more than 10 km. That sounds quite generous and safe, but it is not necessary. Usually, motorcycles and cars use 4-stroke engines, where engine oil is pumped from an oil pan to various places, including many bearings, the crankshaft and the pistons. To ensure proper lubrication, the whole oil inside the whole engine block needs to reach a certain temperature. In some cases the water coolant temperature reaches its operating temperature even before the engine oil. There is no such thing on the RS 125.
The engine in the RS 125 has reached its necessary temperature as soon as the coolant water reached its operating temperature. There is no oil circuit that has to be warmed up. We are not interested in the gearbox temperature, because no hydrodynamic slide bearings are used here, the gearbox runs fine even if it is still a bit cold.
Due to the missing 4-stroke oil circuit the warm-up time is much shorter compared to a 4-stroke, but due to the longer piston and its bad lubrication by the oil and gasoline mixture, warming up is way more important.