The rain doesn’t care about your spare parts.

It starts with a smell. That first proper rain after months of heat petrichor, wet tar somebody burning leaves somewhere. You pull the bike out. The RX fires on the third kick. You think perfect. Then you ride into the season and the season starts riding you back.
Kerala monsoon is not gentle. Three months sometimes four. Roads that were already rough gets worse. Water gets into places it shouldn’t and your spare parts the ones you thought were fine begin to quietly disagree.
This isn’t about panic. It’s about knowing what to expect before it happens.
What the water actually does.
Moisture is the enemy of metal. Every monsoon, humidity stays above 85% for weeks. That alone accelerates rust. It’s corrosion inside electrical contacts, it’s the slow seizing of fasteners, it’s brake cables that feel fine until they suddenly don’t
The RX series are old-school bikes. Minimal electronics simple
But simple doesn’t mean immune.
The older the bike the thinner the protective coasting the more the monsoon finds its way in.
“By the time you notice the problem, the part has been failing quietly for weeks. The rain just accelerates what was already coming”
Parts that take the worst of it
Not all parts suffer equally. Some are exposed directly. Others are affected indirectly through vibration, heat cycling and the constant wet-dry pattern of monsoon roads. Here’s where it hits hardest on your RX.
• Spark plug
Carbon builds up faster in humid conditions. Misfires start subtle. You’ll feel it on inclines first.
• Brake cable
Water enters the housing rusts the inner wire. Feels stiff then snaps without warning.
• Chain and sprocket
Constant mud splash strips lubrication. Stretch and wear happen three times faster than dry season
• Air filter
Wet air, fine mud, dust paste a clogged filter starves your engine. Check it every two weeks.
• Carburettor jet
Moisture in fuel causes gymming. Rough idle, hard starting classis monsoon carb behaviour.
• Mudguard stays
Constant vibration + rust= cracks at the mounting points. Mudguard starts wobbling before it snaps.
How fast do they actually wear?
This is the thing nobody tells you. The wear rate during monsoon isn’t linear. It’s exponential in certain parts especially anything exposed to direct water splash or road grit. These are rough estimates from real-world riding in south Kerala conditions.
Chain life-85%
Brake cable-78%
Air filter-65%
Spark plug-55%
Mudguard-40%
The parts you stock before the rains come
There’re two types of riders. The ones who stock spare in April, before the first cloud. And the ones standing outside a closed shop in July wondering why they didn’t listen.
A spare spark plugs costs almost nothing
A snapped brake cable mid-ride costs much more than money.
Stock it before the season. Not during not after.
Monsoon started kit- series
One spark plug. One brake cable, front + rear. One air filter chain lubricant carburettor cleaner+ a spare jet two mudguard mounting bolts with rubber washers. That’s it. Fits in a small bag. Costs less than a bad breakdown will.
What to do while the rain is still falling
You don’t have to stop riding. Just change the schedule. Instead of checking the bike every month, check it every two weeks during monsoon. Quick checks, not deep dives. You’re looking for three things chain tension, brake feel and the sound of the engine on start-up.
The chain should have a little movement but not sag. The brakes should bike without excessive travel. The engine should start smooth and hold idle without hunting. If any of those three changes between rides, something is wearing faster than it should.
“The monsoon doesn’t break that are looked after. It only finds the ones that were already ignored.”
Genuine vs copy parts it matters more in the wet
This one’s worth saying clearly. During dry season, a cheap aftermarket cable might last you six months and you’d never know the difference during monsoon the same cable might last six weeks. The galvanization is thinner. The housing material absorbs moisture differently. The inner wire corrodes at the joints first.
For a daily rider in heavy rain, genuine or quality OEM-spec parts is not an upgrade. It’s just the baseline. The math works out. Replace twice as often with cheap parts, or once with the right ones.
The RX100 and RX135 have been around long enough that genuine-spec parts are available if you know where to look. That’s exactly what motolab stocks parts build to the original spec, not just approximate copies.
Quick note on availability
Motolab carries monsoon critical spares for the RX100, RX135, RX-Z and RX 5 speed brake cables, air filters, spark plugs, mudguard hardware and more. All OEM-spec ships from Palakkad. Check motolab in before you need it, not when you’re already stuck.