Re: Effects of Riding in rain on hot engine

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The difference is that when you are riding in the rain, the engine is running when it gets wet. On the other hand the water on hot switched off engine is bad.

Same thing with radiators, never fill water in a hot engine which has been switched off. Fill water while the engine is running.

Same thing with cycling as well, never cycle hard and then suddenly stop to drink water. Drink water while on the move.

I do not know the physics that dictates this, but experience tells me it works

Others might be able to give a more lucid explanation!!!

Re: Effects of Riding in rain on hot engine

I think to really see the ill effects of cooling a hot engine rapidly, you will have to splash really cold water/liquid nitrogen on a real hot engine case. The engine case metal can crack immediately or become brittle over time.

The physics involved is quite simple. Consider the metal to be made up of molecules holding hands together. When the metal is hot, you have the molecules dancing around in a vibrating frenzy, eventually spreading out and expanding the metal. When the metal gradually cools down, the molecules calm down, come together and settle down together peacefully. But if you were to dunk your really hot metal into something really cold, the molecules go WTF! and instead of reaching a cohesive equilibrium, are stopped right in the middle of their dancing frenzy. It's like someone called 'statue' and they stopped dead in their current position. This causes their hand held bonds to become weak and crack if considerable outside force is applied.

However, I believe, riding in rain will not cause such conditions in real life. So it's all safe

Re: Effects of Riding in rain on hot engine

From what I can guess, when running, the external layer of the engine case is already being cooled by flowing air. When water is splashed on this condition, there is not much temperature difference between similar air-cooled amd water cooled layers. So not much ill effects when riding in sudden rain.
On the other hand, when the bike is stopped in a place, the air flow is stopped and causes the external layers to be at relatively high temperature. When this layer makes contact with water, it cools immediately due to high temperature difference. This eventually leads to cracking or weakening of engine case.
This is purely my guessing. Experts correct me if I'm wrong..

Sent from my C6903 using xBhp Connect mobile app

Re: Effects of Riding in rain on hot engine

Been riding my CPR several times in rain & from that little experience...
1. Jaipur to Bombay, almost 20% of the distance (From Jaipur to Ajmer; from Surat to Manor)
2. Madras to Pune, about 50 Km in heavy rain
3. Several times (about 10-15 times) on short 20 Km stretches to office
4. Kanchipuram to Krishnagiri like soaked cloths in Washing machine for a distance of about 155 Km
5. Mild rain around South Goa, which is almost nothing compared to the rest of this list
6. TVM to Bangalore for a distance of 25 Km under super heavy rain (read visibility affected)
7. From Walayar to Koraty for a distance of over 100+ Km under super heavy rain (read visibility affected)

Once I had a very good experience of riding my Rx during 2004 rain in Madras in T.Nagar with water level up to crankcase with exhaust completely submerged under water + several commute from office to home from drenched to soaked; there were steam, but the bike held up good. This is 2S.

So far the bike is holding up good & from my little experience, I think there's nothing to be worried about provided the bike is serviced & well maintained & taken care off to worry on effects of riding the bike in rain & the engine getting affected due to it

Re: Effects of Riding in rain on hot engine

Thanks everyone!

Re: Effects of Riding in rain on hot engine

Guys, how about you are riding the bike for say 10k or more, the engine is super hot, and from nowhere the rain starts and that too heavy rain. And you are forced to stop the bike and get somewhere to not to get drenched. The water spills on the engine. How bad is that ?

I have been/seen such situations and could see smokes coming from the engine because of the rain water spraying on to the engine. How bad it could be ?

Thanks
Peeths

Re: Effects of Riding in rain on hot engine

The engine outer layers would mostly be cooler and so not much effect can be seen. The smoke is just water vapour evaporating from the hot surface. Moreover, only if the crank case had any manufacturing defect, it would crack or deform. Every metal has a fatigue point and this scenario is just one in a million instances that's required to crack a metal by fatigue or sudden contraction. If this happens every day, even then it'd take several years to crack a well moulded engine case using sprayed water.

Sent from my C6903 using xBhp Connect mobile app

Re: Effects of Riding in rain on hot engine

Thanks mate . That make sense .. was just curious to know ..

Thanks
Peeths