Hey,
I'm thinking about powder-coating the cylinder and cylinder head as well as the side covers from my 75' DT250.
I have found a company that uses high temperature powder for engines.
Are the cylinder and cylinder head originally painted or powder coated? Can there be problems with heat dissipation?

I already asked it in another thread, so I hope its okay that i start another thread just for this question. I thought the question would reach more readers here


 

Hi, in 1970ies, there was no powder coating.
Heat transfer with powder coated parts is lower becaus of thicker layer, so i wouldn´t coat Cylinder and Head (even if Harley does so)
Right side covers coating im matte Black looks nice and is no problem.
But left side is too risky, parts are made from Magnesium. Dont ask, how i know...

Hey, what do you mean by left or right sides?
The DT250B has a completly black gloss engine. Both covers are black. Under the left side is the ignition and drive sprocket.
All covers are made from Magnesium, its written on the covers :-) Do you cant powdercoat magnesium alloy or whats the problem?

So maybe it would be better to paint the cylinder and head with 2K paint and to powdercoat the covers.
Powdercoated head and cylinder would look much nicer, but i dont want thermal problems as well... But another tought i had: I drive 90% on asphalt roads. I guess the motor is thermally designed for offroad use with low speed at high RPM.
For me its a oldtimer i wouldnt torture with bare offroad. Maybe some forest paths but mostly asphalt. So there will be more heat dissipation.

If you keep asking, eventually someone might come along that tells you what you want to hear.  

What is the coating thickness and how hot will your guy get the parts get during baking?  Warping and damage could occur, especially to the cylinder made of iron surrounded by aluminum.  (I've heard of baking temps of 400C or about 750F...  which is much hotter than cylinder would ever get...  would that cause the sleeve to warp or separate from the aluminum?)

The point about magnesium is a good one.  Magnesium is volatile and can be difficult to even paint.  (I would NOT strip the original paint)

Good luck with whatever you decide!

 

Maybe look into ceramic coating as this is designed to help heat transfer.
I've no experience with it myself.
Like other far more experienced members of this forum have said I wouldn't powder coat.

ceramics help PREVENT heat transfer
think before you speak

Just have it vapor blasted & leave it Au Naturel.

Hey, thank you for all your messages. I decided to sandblast and then powdercoat the engine covers and carburator and paint the cylinder and head. Both in gloss black.
But now i read that powdercoating magnesium alloy is also problematic. I will talk to my sandblast/powdercoat guy about this later. When he said it wont be possible, i will talk to a paint shop about this.

I think i will find a solution for a new looking black engine :-)

Power coating of Magnesium parts, in my case , went wrong. Air bubbles went out of the surface and create holes in the coating. And material reacts looks like puff-paste.
When I wrote " left side" it's ignition cover and sprocket cover. Right side is clutch cover and oil pump cover. Some right side covers are Magnesium,  some Aluminum. Better not coat Magnesium. 
And:
Hight temp powder coating is very brittle and not really the right black colour.  Let them show you a sample. Had it on my Harley muffler-never again.

So i talked to the workshop and he confirm what you all said, its not easy to coat Mg-alloy.
Sandblasting could create holes in the material and powdercoating could leave some holes and air bubbles in the coating.
I tried to contact some paint shops, but until now i only got bad reactions.

Its nice to know that some of the covers are Mg-alloy, some not! I thought all of them will be Mg-alloy.
But i think it doesnt look good, to paint/powder just some of the covers.

When i dont get any positive reactions from the paint shops, i will just coat the cylinder and head with normal heat resistant paint from the can and leave the covers with its original paint... Like some of you already told.
But at least the Mikuni Carb gets a new powdercoating. I hope its just normal Al?

Dont tought it would be so difficult to paint some covers :-D