Engine Heat

[ken]

On the day I rode my Nomad from home (Hamburg, Germany area) to Frankfurt it was a unusually warm when I noticed what I considered excessive heat radiating from the left side of my rear cylinder. Given the ambient heat of the day, i didn't think too much about, but noticed that the heat continued on latter short rides. As I was due for an 18,000 KM service, I mentioned it to the mechanic when I took it into the garage. When I picked up the bike a few days later, he indicated that they measured the heat all around the engine and it was within acceptable limits. I’ve experienced no problem with the bike at all….runs good, no heat light, all fluids OK. Hummmmm

Then I thought…I have one of these extra loud horns (Strebel?) mounted on the left side under the upper part of the highway bar. I also mounted driving lights on the highway bars about halfway down and on the inside of the bars.

Question – does anyone think it’s possible that the light and the horn on the left side are hindering the airflow and as a result, doesn’t allow sufficient cooling air to reach the rear cylinder? Thoughts please. ???

[Top Cat]

It is a liquid cooled engine. I don't think air flow would make a noticeable difference.
I get a lot of heat when the fan kicks on. I think you are fine, nothing to worry about.
Of course I'm no mechanic either ;)

[cactusjack]

It's an internal combustion engine. It generates heat. It is also liquid cooled. I wouldn't worry about it.

[trosco]

Ken, actually we have air/water cooled motorcycles and the fins on our cylinders are very much functional air cooling fins. Most of our water jacketing and hence water cooling is in the cylinder head area.
I have a 07 Nad, and I removed all of the stock intake system on left side of bike and the crossover between cylinders. Put a Hyper-Charger on right side. I experienced a dramatic increase in air flow left to right between the cylinders. The Charger creates a low pressure area behind itself and the air from the higher pressure flow on left side of bike moves between the two cylinders to occupy the lower pressure area on the RH side. As it moves across the left side and then between the cylinders and then out across the rear cylinder and the rear cylinder exhaust it gets very very hot. I experience this heat on the Hamstring area of my right leg and my right buttock while my left side is unaffected by heat. Very uncomfortable!
I am in the process of modifying the Hypercharge cover to reduce this effect and I am looking at installing a horn & chrome cover in the area that used to be occupied by the left side air cleaner. I am hoping that I can cause the flow to go behind the charger, between the two cylinders right to left and out on the left side behind the horn. Thus creating a move even distribution of heat.
You could have easily created a similar effect with your horn additions.

[ringadingh]

The Stebel and lights you added are probably blocking some air flow, and making it feel warmer on your leg. But its not enough to make it run hot, just enough to make you notice a difference between sides of the bike.

[jamiep24]

I can't answer that but come January and February, I'll be huddled-up around that hot motor as close as I can get.

[jonsamson]

I thought maybe you weren't driving fast enough, faster you drive more airflow less heat.

[macmac]

Originally Posted by trosco

Ken, actually we have air/water cooled motorcycles and the fins on our cylinders are very much functional air cooling fins. Most of our water jacketing and hence water cooling is in the cylinder head area.
I have a 07 Nad, and I removed all of the stock intake system on left side of bike and the crossover between cylinders. Put a Hyper-Charger on right side. I experienced a dramatic increase in air flow left to right between the cylinders. The Charger creates a low pressure area behind itself and the air from the higher pressure flow on left side of bike moves between the two cylinders to occupy the lower pressure area on the RH side. As it moves across the left side and then between the cylinders and then out across the rear cylinder and the rear cylinder exhaust it gets very very hot. I experience this heat on the Hamstring area of my right leg and my right buttock while my left side is unaffected by heat. Very uncomfortable!
I am in the process of modifying the Hypercharge cover to reduce this effect and I am looking at installing a horn & chrome cover in the area that used to be occupied by the left side air cleaner. I am hoping that I can cause the flow to go behind the charger, between the two cylinders right to left and out on the left side behind the horn. Thus creating a move even distribution of heat.
You could have easily created a similar effect with your horn additions.

Now that's interesting as all heck. I agree 2.5 quarts of coolant isn'rt the ALL if cooling these bikes. it keeps things closer to a sort of constant, which assists in tighter tolerances over all engine wise.

A stock bike with a goat belly will toast you on a hot day on both sides..

Get rid of the damnned thing, and it can be cooler around the legs..

The fact a hyper charger is a wing only sideways never occured to me, but there are days where my naked left side is far cooler than my Caddman right. hmmmmm

[AlabamaNomadRider]

I only feel the heat while stopped. When running down the highway I usually don't feel much heat.

When the fan kicks on you feel the heat, it blows right on you almost. These are big engines, they're going to generate some heat. Some people say synthetic oil cools them down some, just a thought.

[bobhamlin]

I just did a complete air mod and Stebel install. The fan is not coming on as often, but I'm definitely feeling more heat on my legs -- and not just when the fan comes on.

When I had an old VW bus, I remember that, after working on the engine, it was very important to replace the nondescript, little pieces of metal that directed the air around the cylinder fins. If the air flow was interrupted, the engine could melt.

Of course, the VWs were not water-cooled like our Nomads.

The cylinders' cooling fins are there for a purpose. They bring heat from the engine, with the intent that surrounding air will whisk it away. I doubt that the stock air tunnel served any cooling purpose because of the thickness of the plastic, however, the aerodynamics had to have changed with its removeal.

Anyone have a spare wind tunnel that would allow us to blow smoke and watch the air currents around the engine?

[dhomoney]

Ken,

I don't think you are causing any problems with your bike from what you have described.

[trevwales]

Engine Ice? http://www.engineice.cc/street_main.html

[dogdoc]

Its a 105+ every day here now, YES, you bet I feel some heat. :-)

[paulo]

I ride with lowers ( hd knock-offs from 'Premeux') all the time---and have not noticed a heat increase----when on the move---my fan does not come on. It does come on when stopped at Lights or in traffic on very hot days----thats normal.