Someone made a good point the other day about kuryakyn engine chrome trapping in heat on the air cool engine.

My question is for guys with fairings (gauges) and engine chrome (inner primary cover, rocker box covers, etc - all that kuryakyn stuff).... Can you really see a difference? Does that stuff trap heat in? I kinda want an inner primary cover... Maybe some of the other stuff too.

 

Yeah everything Ive read indicates chrome doesn't dissipate heat real well. I put a black oil filter in but in the grand scheme I doubt that does much. But whatcha ya gonna do, its a motorcycle and most are loaded with chrome.

 

The inner primary can be changed easily, and I would do that over a cover. The price is a bit more, but it's money well spent. I did the chrome inner on my Spftail, and it's a big difference in appearance.

As for heat, I think it's all relative. With a 2012 and the oil cooler, you're in decent shape. The amount of heat added by chrome, if any, is probably far less than what you removed by adding your pipes and a good tune.

 

A chrome primary cover isn't going to trap a whole bunch of engine heat. If you are asking for feedback from those with oil temp gauges its really not relevant because the engine, primary, and trans are all independent lubrication system, not much cross-mojonation going on. As long as you aren't chroming the cylinders and heads there should not be a significant heat consideration, bling it up.

 

I'd always thought the matte black/denim was the real problem with heat build-up and retention?

 

There is no simple explanation to air cooling:
- When we move, air is constantly refreshed and all surfaces are cooled by conduction (color is less important).
- At standstill there is less conduction and we rely more on reflexion (dark is preferable).

Cooling of chromed surfaces is not very efficient at standstill but convection will occur (by conduction) and help thermal exchange. Thickness, surface texture and nature of materials also play their individual roles.

The only efficient way to accumulate heat is to remove air (vacuum).
The risk with a large chromed surface is to touch it when its hot because it sends a partial thermal 'signal', like an iron (for ironing textiles) as opposed to a dark surface where we feel heat emission.

Finally, chromed and black air cooled engines become even when they get dirty

 

Absolutely agree there is no simple answer when we're talking thermal dynamics. However, the OP asked a rather focused question. You are obviously well versed on the subject, so do you think a chrome cover over the inner primary case is going to retain or increase engine or oil temperature to a noticeable or even measurable level that will be cause for concern, clean or dirty?

 

I replied using the word 'thickness' and nature of materials

You have aluminum alloy, gasket paper, a quart of oil and a fixed volume of enclosed air sandwiched together.

The engine is far away from the primary cover and its 'heat transfer path' to the primary cover is distant.
It needs to pass:
- through the crankcase oil gasket to reach the primary,
- through the inside/rear mass of the primary housing,
- through the gasket of the cover,
- to finally warm up the cover before it can diffuse in air.

With a clean engine:
You will have a very small influence of engine temperature buildup due to low emissivity of the (shining) cover because of all the thermal obstacles along the thermal path.
With a dirty engine:
Mud or cow dung don't allow exposed surfaces to cool efficiently so temperature will rise slowly while riding and faster at standstill.

The only combination that must be avoided by all means when cooling is required is a warm surface standing behind a polished cover like our exhaust heat shields. Exhaust gases must be kept at a high temperature to assure complete combustion, engine oil not.

 

I think you are right on. I thought about putting some chrome pieces on my motor, but they HAVE to trap heat in/make it harder to dissipate...very bad idea with an air cooled engine. They also say air is a good insulator, so you put a piece of metal on your motor in a bunch of places and trap a layer of air in between. Then the heat has to go through your motor, the air, then the added metal to escape...seems like a real bad idea, just for looks and saves a bunch of dough not doing it. I don't mind seeing some nuts and bolts, etc., on a bike...it's a machine, machine use nuts and bolts to hold stuff together, reality! Ride safe and cool.

 

The "Does chrome make your engine stuff hotter" issue has been around since the 70s at least. The general consensus was that it can increase temps on certain parts and to some degree, but whether or not it becomes harmful has to do with how much chrome and where it's placed as Expat explained in tech terms.