PC head kz900

what problems am I gonna have powder coating the head? Valve seats fall out? Warp? I am going to put old springs back in and leave the new valves in. remove the guide seals, and bake. what have I not thought of?

Valve guides moving around would be more of a concern to me,I don't see the seats being a problem.
Cylinder heads generate a lot of heat from combustion chamber,powder coating it could cause over heating issues with motor is my biggest concern.

shadow44 wrote: what problems am I gonna have powder coating the head? Valve seats fall out? Warp? I am going to put old springs back in and leave the new valves in. remove the guide seals, and bake. what have I not thought of?

If not already done, before proceeding, would first inquire of a professional powder-coater as to whether the powder coat finish will stand up to heat generated by the engine head.

Bettin' my nickel on not being a good idea to powder-coat the head. :lol:
(But I lose lots of nickels.)

Good Fortune!

Powdercoating engines is common and the heat won't make it fall off.
Got a motor here that's coated all over.
Strip the head bare and mask off the areas not to be coated, don't leave in any valves etc.
The guides shouldn't move as the pc bakes at only 180 deg and you would have to take a drift to the guides to shift them.
As mentioned earlier heat dissapation problems is possible especially on air cooled motors and i personally don't like engines done which is why i'm stripping the pc off the one i have.

180 deg? This stuff cures at 400 deg. :blink:

Zed is in England so it may be that 180 is in Celcius and your 400 in Farenheit....good to check either way

A lot of pc Harley' motors and heads out there.

This place claims no heat issues.

figurefinishing.com/?page_id=1262

Q: I saw powder coated finned (air-cooled) motorcycle cylinders and heads in your portfolio. Does powder coating affect cooling? A: No. Powder coating is a poor thermal insulator, so the engine temperature is not affected. If you have an oil temperature gauge, you won’t see the needle move. If it runs at 205*F in traffic on a hot day prior to coating, it’ll run at the same temp after coating. I’ve even seen an HD rider claim his black powder coated engine runs 4*F cooler than it did bare. I would probably attribute that number to either variation error in measuring temperature or to slightly different external conditions, since I doubt this was a controlled test. Also, most engines – air-cooled or liquid – are powder coated from the factory, including Harley Davidson motors, which are powder coated to look like a rough aluminum casting (i.e. like they weren’t coated at all). The color is called “Harley Davidson Bead Blast,” which we stock along with the similar but darker “HD Warlock Grey.”

Q: How does powder coating hold up on finned (air-cooled) motorcycle cylinders and heads? Can it handle the heat? A: Powder holds up great on motors. Most powders are baked at 400*F, and most engines shut down at 250*F, Harley Davidsons included. Also, powder technology has been progressing aggressively, and most powders have an excellent overbake stability, easily exceeding 450*F operating temperatures without failure.

I don't know if that's really a fair comparison considering the the Harley heads are separate with exposure to 360 degrees of cooling for the most part,where as the kz cylinders are siamesed with no real source of cooling between individual cylinders
Maybe off topic,but what the hell aint aroun d here right?
Anyway I remember being told in my much younger years by somebody much smarter than that gm did some sort of test in 60s/70s comparing heat dissipation with various colors of engine paint.
According to my source back them gm discovered the dull black worked best for heat dissipation,thats why the gm high performance crate motors you buy through the dealers were and still are painted black from the factory.

bluezbike wrote: Zed is in England so it may be that 180 is in Celcius and your 400 in Farenheit....good to check either way

Yes! 180 deg C.

Thanks for the input folks, I appreciate all of it. This bike is special to me, not just for what it is, but the whole history behind it. I am getting ready to head to the garage, and powder coat this head. given all the input from everyone I think PC is the way to go. This is not a race bike, so heat should not be too much of an issue. So wish me luck, I will try to post some pics tonight of the finished product.

here we are! now back to the machine shop as soon as my new guide seals get here. :whistle:

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