its liquid cooled, right?

[Old Wild Bill]

You should let the fan run until it shuts off then shut the engine off. I don't know if the Honda fan runs with the ignition switch off, but on my GM cars the fan runs until the engine cools down.

[Easy Rider 2]

Originally Posted by maurice1

overlycautious

Now THAT'S an understatement.

Only 2 conditions when you should let the bike idle more than 10 seconds or so before turning off:
1) The fan is running
2) You rode it REALLY HARD right up to the driveway.
Even then, 30 seconds to a minute is plenty.

99% of riders turn theirs off immediately; 99.997 % of those never have a heat related failure. Don't worry about it. (Yes, I made up those numbers!)

[qwertydude]

Getting rid of the hot spots is true, it's the heat soak effect, after riding your bike hard it takes time for the hot spots to transmit their heat to the oil and cooling systems, but if you're running hard enough and shutting down abruptly enough to cause any long term damage you might want to consider running synthetic oil, the hot spots do their damage by heating the oil and breaking them down.

It's arbitrary though because the Honda Shadows are 9.0 to one compression ratio AND liquid cooled. I think this is a very low stress engine because my previous air cooled GS500F has the same compression ratio, is higher revving and air cooled only, it beats it's oil harder than the shadow and is a known durable engine that can go 100K miles if well taken care of, so I think even in this case heat soak is a non event.

I don't think you have to worry about the Shadow too much because on top of the liquid cooling system, water has a very high specific heat capacity and just the presence of the water alone will prevent hot spots from doing any real damage, and there are even cooling fins on the engine even though they're merely decorative they'll dissipate quite a bit of heat just being there. Also turbo chargers are only air cooled and do have to worry about heat soak.

[litnin]

Originally Posted by qwertydude

Also turbo chargers are only air cooled and do have to worry about heat soak.

Uh... no, turbo chargers are not only air cooled.

Turbo chargers use oil for primary cooling and some are liquid cooled.

[litnin]

Originally Posted by maurice1

i may have to change my screen name to overlycautious, but i am now a little confused. At first i thought the idea was just to make sure after a ride to let fan turn off if it was on at the time one stopped. After reading a few more posts, looks like depends on hard ride vs less hard ride will determine how long one waits to turn off bike. Did not sound like fan on or off was the determinant. A little clarity please. thanks

overlycautious

No, I think some people are trying to make it seem like I said something
is going to blow up if you don't follow my advice and are trying to make
what I said a little more exaggerated than what I actually stated.

Let's go back and read what I wrote.

Originally Posted by litnin

Although 99.9% of the people don't and won't do this, that is a good idea.

It's a good idea. Not mandatory, not your engine will blow up if you don't,
nor any other negative comments.

I explained what happens with the cooling system when you just pull up and stop.

Then I said:

Originally Posted by litnin

Generally, it won't cause any short term damage, but over a long period
of time, it can give your cooling system a little bit more time between part failure.

That means just that. You'll might get a **little** more life out
of cooling system components if you let them cool down gradually rather
than expose them to thermal spikes.

Regardless of what some other people have said that appears to try to
exaggerate what I said, it isn't that critical to do... but it is a good idea.
Just like not eating dinner one night. You're likely not going to die from
starvation, but it's a good idea to nourish yourself each day.

[maurice1]

ok litnin. It was not what others said that confused me, but rather when you lastly stated "The thing is to gauge your engine load before shutting down.
If you were out carving the canyons, then you want to let it idle for
a bit longer.
If you were puttering through your neighborhood at 10-15 mph,
then you can reduce the time.

First it was stated to judge turn off by if fan is on or off. that was simple. the above statement sounded a bit different. sometimes even when i have not been riding hard, i come to the garage, get off, open door, get back on bike and fan just kicked on. I now will just let it idle until fan shuts off before killing engine. thanks for clarifying.

maurice

[gggGary]

I would not trade an idling engine for theoretical cooling of hot spots. I do have a gravel driveway and have to go slowly up that. Enough for me. If you are really paranoid about this rewire the fan circuit so it is independent of the ignition switch. That's the way my old KZ1300s were set up from the factory. Often as not the fan would turn on AFTER I shut it off on a hot day. These engines as mentioned are well finned and really hang out they are not packed inside of a bunch of body work. My ACE 11 fan came on quite a bit when i first got it. The coolant bottle was opaque so I added some coolant and the fan comes on less often now. Or I no longer notice it. (still warm here) Still can't say for sure if it was low. There was coolant up to the neck in the cap under the gas tank.