just my gut feeling, and I really have no science to back it up but I would turn off my bike if it looked like it would be more than a few minutes. I mean what is the point of just letting that heat build up, and you just marinating in it? If it was a car and you had the AC or Heat I would be more inclined to let it run.

Here is something to think about, although totally different scenarios (iron block vs aluminum) - alot of diesel service vehicles are NEVER turned off. I have watched power trucks come out after storms to work in our neighborhood and the trucks just idled for hours, and they had been idling for days at that point working through the storms.

 

well I would think that you have already built up heat and turning it off wouldn't make it marinate any less. I prefer to let my cuts marinate over night in the fridge...

But seriously, I would think that circulating the oil would be better than letting it heat up and sit.

 

I am not a certified mechanic so take this for what it is worth but I don't see how letting a motor idle hurts it. You hope that Honda engineers are bright enough to build a motor so that idling will not hurt it cause lets face it your motor is going to idle no matter what. I feel like I do more idling on the way to and from work then I do moving (Stupid traffic). I think of it like walking and running. I get a whole lot more tired when I am in a full sprint than when I am walking. So to me it makes since that idling is good for an engine because the parts are not moving up and down so fast, less friction and all that. Now yes as the motor sits there and idles heat will build until it hits the point where the fan comes on to keep it roughly at a constant temp. I sure hope Honda built these things to withstand that temp otherwise we are all doomed. Just my

 

Do you turn your bike off when you get done riding and put it in storage for the night? Your engine isnt going to be magically unlubricated from waiting on a train for 5 mins.

 

I kill the bike even at long red lights. Mostly so i can just rest in 1st gear without holding a the brake. Also helps not roast my crotch on hot days from the fan being off.

The theory that you use more fuel on startup is with CARBED bikes and cars, and who the hell has them anymore lol (i kid, i kid). With Fuel Injection, save some gas, some heat and your fans by turning it off its its gonna be a fews minutes. If your running it your just wasting precious, and expensive gasoline. I use my gas to go forward, not to sit.

 

That wasn't really my point. I'm saying that whether you turn it off or leave it idle I don't think it makes much of a difference. Additionally, the bike will continue to heat up slightly after you turn it off because the coolant has stopped flowing. I just don't think it matters. CBRforum members have 150,000 plus miles on their motors, I doubt idling for more than 5 minutes would have changed that.

 

Heat transfers from hot to cold. Logic would tell you that when you turn off the engine, seizing all work, that it is going to cool down. No its probably not going to cooldown 10 degrees in 5 mins or even a degree at all. The only thing you benefit from turning your bike off at a standstill is savings in gas.

 

If you cut a bike off as it is heating up - ie, you are coming to a stop light and you come to a stop and turn it off then the heat will briefly BUILD, as the cooling capability of the engine via cooling antifreeze and cycling it through the engine is not available because you killed the bike. SO - heat will briefly build and then begin to cool off, and these aluminum blocks will dissapate heat very quickly.

Letting one of these bikes run for 5 or 10 minutes would burn almost NO fuel so that isn't a concern.

Just do whatever makes you happy because it isn't going to matter either way.

 

I'm not quite sure where you guys are getting this idea that when you turn your bike off its going to get hotter. Yes the cooling system turns off but so does the engine. There's no more friction, detonation, or work period. How does something get hotter when you arent adding any elements of heat? When you take a steak of the grill it doesnt magically get hotter than it was on the grill. It continues to cook because its still hot, not because its getting hotter.

 

Good stuff everyone...everyone has valid points...to the guy asking about 20 minute trains...midwest yes Illinois, suburbs of chicago! Now I live in AZ...which is just great for the heat aspect we speak of

Anyway..I feel that when you do a brief shut down of the bike/motor at lets say a long light etc..the motor's internal components become INITIALLY immediately very hot...this is due to what a previous poster stated that there is no coolant flowing and the pistons etc have just siezed from moving! Yes theres oil in there...HOT oil...and it is cooling the internals somewhat along with the coolant, but this sudden stop of movement of parts causes an INITIAL (keyword) buildup of heat....now should you start right back up in 5 minutes, that engine is HOT and mt "theory" is that degradation would occur here rather than letting her idle and "flow" through the heat/cooling cycles of the fan/coolant temps...Anytime you stop moving parts when they are quite hot, you are taking away the necessary cooling the parts had when running...that initial heat buildup can cause stress on components once forced to move again in such conditions...

A half-a$$ example would be when my old trans am GTA L98 motor would get hot (220ish) and I would shut her down, sometimes the starter and other components would get so hot that they would not work until the car sat for 2 hours! The heat killed shi^! Now given this is not a great example but you get the point. Oh ya...that motor ended up throwing a rod! And I didnt even go nuts on it for most its life!

my vote is keep the motor idleing when in short stop conditions and make sure your fans and cooling system are doing their job..From what I read 250 is overheating and you should never see past 230 as the fan is on around 223ish? My vote is to shut er down if your going to be sitting for more than 15min