Q. How much monthly maintenance cost of Yamaha R15s ?

Once the free service intervals are over, its not a monthly affair anymore. But if I had to sum it up for you, I spend roughly 12,000INR easily per year in the name of maintenance for R15S which includes front and rear tyres as well, so its approx. 1000 INR/month. I have completed 4 years and 47,000Kms on my R15S, and the above figures are from my personal experience. I prefer to use brands like Motul 7100 4T 20W50 engine oil, JK Tyres, ROLON chain sprocket kits and Versae Sintered disc pads, branded chain cleaners and lubes and I like to pamper my bike so that even after putting it through rough terrains, long distances, stressful rides it still stays in mint condition and perfectly smooth. So I annually spend around 12,000 INR which is not that expensive in my opinion.

If you keep the service intervals between 2500km to 3k KM's the engine will run smooth and the service cost is minimal at around 1500rs to 2400rs