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Aircooled Engines Overheat at Long Idle?

P

Pspice

Just got it firing!
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Hello forum,

Generally, do air cooled engines need to be turned off when idling for prolonged periods at stop? Especially cylinders inline with frame (essentially 90% of the other v-twin placement configurations)?

What about the Moto Guzzi V7i-ii (stock) or other larger Guzzi motors (Griso, Cali, Audace, etc)? Im sure ambient air temps matter but I really have no idea since the bike does not have an engine temp gauge (i know, no coolant).

I've contemplated if I need to shut my engine down when stopped at a red light.

Appreciate some wisdom and education!

Happy St Patty's Day weekend
 
I don't think there is any need to be concerned about overheating unless it is in heavy traffic stops of more than traffic light times. One reason to use the 10/60, it sheds heat.
If you are worried about the temp, they sell screw in temp gauges for dipstick.
 
A mag. (Mcn i think) Did an article years ago proving that at each firing of the cylinder the heat radiates out through the cylinder fins. When you shut it off the piston and cylinder cool at different speeds causing mini seizures of the piston. So don't shut it down unless it's going to be a long wait like for a train.
 
You do not need to shut off your engine at stop lights under normal circumstances. High heat days while sitting in traffic may cause overheating, where the motor will run poorly. Best to shut them off in that situation. The worst thing people do is to start and let them idle for extended times sitting still. Modern engine designs are best to start, and once the oil has begun circulating (for all of about 5 seconds), go.
Those oil sump temp gauges Steve talks about above will scare you. Don’t do it. ;)
That and most of the steel rod designs snap off and drop into the motor. I’m not a fan for both of those reasons.
 
Thank you Todd. As a matter of fact, you installed one on my motorcycle not too long back.

I agree that the larger oil capacity and integrated fins help keep fluid temps from getting out of control and prolong oil change intervals.

No leaks! You and your staff's workmanship is great!
 
Great question I've been wondering about this too.
Since we have no coolant to boil off, I wonder what are the symptoms of overheating? Todd mentions running poorly. Is that lack of power? And everything returns to normal after cooling off? At what point do we worry about permanent damage or is the cooling design so good that, unless sealed in a box, the engine can cool itself enough to prevent damage?
 
avlis said:
Great question I've been wondering about this too.
Since we have no coolant to boil off, I wonder what are the symptoms of overheating? Todd mentions running poorly. Is that lack of power? And everything returns to normal after cooling off? At what point do we worry about permanent damage or is the cooling design so good that, unless sealed in a box, the engine can cool itself enough to prevent damage?
Click to expand...


You guys worry too much. In NH it isn't hot enough for cooling to be much of an issue. Basically don't sit still any longer than necessary. If you are where you are stuck in traffic and will be for a long time just shut the bike off.
 
I have historically had more issues with water cooled bikes overheating than air cooled bikes. I did have an air cooled bike that actually had an electric cooling fan (it was a Buell). But for most it isn't required.
 
Right! My GF has a water cooled SV650. Our first long-ish ride with my then new V7III last summer landed us in some traffic at our destination a couple hundred miles from home. Her bike's temp light came on and so did some amount of panic. We pulled out of traffic to let her bike cool. The fan wasn't running which I thought strange. I looked it up later and seems the light comes on well before the fan and that comes on well before it overheats. Which got me wondering about the heat susceptibility of my V7III.
 
On all my trips, across the USA, I met Harley owners, in Gas Stations, having to wait for the rear cylinder to cool down !
My Breva 750 never , ever ,had an overheating problem!
In the queues to cross the bridge from Canada to the USA etc.
One year, while visiting the National Prairie Grassland ( Oklahoma ? ) we were over 130 deg, We did a quick run around & took some photos, then got back on the road, to get some air movement.
It bothered us, more than it did the Guzzi !
 
How are air cooled ducati's, HD's, and Yamaha Bolts keeping the rear cylinders cool? Is it typical for manufacturers to make the aft cylinder and head not equal in design to the fwd cylinder for improved thermal capacity or cooling?
 
Pspice said:
How are air cooled ducati's, HD's, and Yamaha Bolts keeping the rear cylinders cool? Is it typical for manufacturers to make the aft cylinder and head not equal in design to the fwd cylinder for improved thermal capacity or cooling?
Click to expand...
Ducatis don't seem to have as big an issue, but it was not uncommon to have the rear cylinder jetted richer than the front. Carbed HDs share the carb, so they could not jet the rear richer than the front. But fuel injected HDs and Buells like I had could run richer at the rear cylinder.
Also, some Buells would run a cooling fan for the rear head. It was a little fan that looked like it came out of a PC. It was on a temp switch, turning it on when it got too hot (like sitting in traffic).
 
avlis said:
What are the symptoms of a overheated Harley rear cylinder?
Click to expand...

Not having had a Harley, I do not know, perhaps they have some sort of temp guage ?
It is obviously a known problem.
All I know is, during my multiple crossings of the USA, each year, from 2006 on the Honda CX 500, then from 2007 til 2018 on the Breva 750, we have met harley riders on several occasions , where they had pulled in, due to overheating.
I never thought to ask, how they knew ?
 
GuzziMoto said:
Ducatis don't seem to have as big an issue, but it was not uncommon to have the rear cylinder jetted richer than the front. Carbed HDs share the carb, so they could not jet the rear richer than the front. But fuel injected HDs and Buells like I had could run richer at the rear cylinder.
Also, some Buells would run a cooling fan for the rear head. It was a little fan that looked like it came out of a PC. It was on a temp switch, turning it on when it got too hot (like sitting in traffic).
Click to expand...

The reason for Ducatis not having the problem, is because the Ducati's engine, leans foreward a lot more, with the lower cylinder almost paralell to the road

Yet, this one seems to be fine ? bikeexif.com/vincati
 
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