Hi ! I’m going to do a small chronical of my bike so I can hopefully give you some info for my upcoming questions , so bear with me
I bought a second hand Dt125r 1997 model, with 38K Kilometers on it at the time of the purchase.
Since then i replaced the cylinder ( cause the old one was scored due to piston breaking at the edge ) , the piston and the small bearing. During the rebuild I noticed some rust on one side of the crankshaft flywheels ( the bike was not used for more than a year before I bought it ) , I cleaned it as best as I could . I don’t remember if I checked for big bearing play and if I did , I did it by feel and not found anything. Also I replaced the Mikuni vm26 that the bike came with due to physical damage ( previous owner mentioned the original carb got stolen and the vm26 was the replacement ) , with a Mikuni TM28ss from a donor bike I had laying around.
Front and real brake discs got changed from the donor bike as well. The exhaust system is a DEP pipe , with an arrow silencer . I also serviced both the expansion pipe , de-carboned it and repainted it ( it was covered in rust ), and silencer.
After the “rebuilt” the bike was used for one year with almost no issues , it has travelled 2300 km, mostly in city riding, including a 270km trip at 110km/h cruising speed for almost 2h ( with breaks in between so I can feel my a** again )
Now to the point of this :
At 40k + kilometers, what should I check as maintenance ?
Is there some parts in the engine and the bike overall that I definitely need to replace or check ?
What is considered a weak point for these bikes ? Meaning , what's the first thing to probably fail ?
Some issues I noticed over the year :
The carb overflows if you leave the tank valve open and park the bike , and the fueling feels to the rich side. Also if you snap the throttle from idling it bogs for a second before it revs up. For the carb , I’m going to order the needle and seat and the bowl gasket . Also probably buy an ultrasound cleaning machine and clean the carb with it.
There are some metallic ringing noises when riding , like if you leave some change in your car and they vibrate to the engine, but way more subtle.
The overall engine noise seems to take a higher frequency aggressively when the engine gets into the exhaust tuning rpm ( around 6500- 7500rpm ). You can hear the change between 5000 and 6500 clearly ( almost like a small supercharger gets activated after 6000 )
The front brake feels like it’s having two grip points as you press the lever, in low speeds the first “point” is enough to gently slow down but if you press a little more it grips suddenly harder. It’s like the breaking is not linear.
Back brake works smooth, but it has a long travel in the foot pedal till it becomes effective.
That’s all I can think of right now. Ask me freely for more details.