TOPIC:

I really like to the look of black engines with the chrome or polished covers. Very much like the Z1900 at the top of the KZRider home page. Are there any draw backs to having a black air cooled engine. I was thinking about going this route when I rebuild my engine.

If I'm correct i don't think many black air cooled engines were made, so i was wondering if the was a specific reason for this such as over heating issues.

tw

I can't wait to hear the answer. I have a black engine. It is a 1980 Mk II.

I am going to need to repaint it soon, so I will piggyback on your question and ask if anyone can recommend a good engine paint.

I had a black engine on my water-cooled triumph TBS and rarely ever heard the fan come on. I have read that a low-sheen, black-colored engine is actually better for cooling than the standard aluminum or polished look.

I believe I read this in the book: Motorcycle Maintenance.

Mandrake

High Temp engine paint does OK if it is cured. In other words, it works OK on a cylinder or cylinder head but not so well on side covers and engine cases which don't get as warm. I know this from personal experience. I like to use aluminum Hi-Temp on my blocks and cylinder heads in general after clean up. Spiffs them up. The block and side covers on the other hand would probably do well to be bake-cured I would guess.

I am currently getting some bits on my project KZ1000E1 ST (shaft) powdercoated using semi-gloss wrinkle finish (mild wrinkle). I had the cases, block and cylinder head done. I have already had the valve cover done flat black. I decided to clean up the side covers and do a bit of trim paint in black... like the center of the points cover and the edge of the clutch cover. The nice thing about powder coat is that you can effectively grind a bit on the fin edges and then wire brush them with a dremmel tool to polish.

I know there are folks that say a painted or powder coated engine doesn't shed heat as well as a bare metal engine. I have not had that experience... have had both and not seen much difference.

I used aluminum hi-temp paint on one of my KZ's engine cases awhile back and that was a mistake... stains and splotches almost immediately... same with engine covers. I also had some powder coat done in aluminum on engine covers and had bad luck with it because the powder coat shop wasn't very good. Get a good shop if you use powdercoat. The stuff MUST bake/cure properly and the cheapo shops don't get the work hot enough for long enough.

Oh yeah, the ST engine was originally painted the same as the MK II and both of mine are nasty and the black is flaky and gray and has some corrosion. I doubt I wanted to spend the time and effort to shoot them with rattle can hi-temp... not sure what the original finish was... paint or powder? Hmmmm I think due to the age, probably heat cured paint.

Post edited by: wiredgeorge, at: 2006/09/15 14:52

low gloss black paint disapates heat really well,theres a reason most bigblock chevy crate motors came painted black from gm:evil:damn picture wont fit!

Post edited by: wireman, at: 2006/09/15 15:41:S

Post edited by: wireman, at: 2006/09/15 15:42

The black on the 1979-80 KZ1000s was definately more than just paint. Not sure what it was, but it was hard as a rock, unlike paint. The 73 Z1 had the black engine that was paint.

Put your fingers in your ears for 60 seconds...Honda had many black engined bikes from NightHawks to CX650 Turbos. Granted the CX were water cooled but the NightHawks wern't. Yammie had a few too. Can't think of a black Suzie tho! Hardley had a lot of them right up to todays NightTrain. Just get you some of that Stove Black for cast Iron Wood Stoves. Just make sure you don't touch it. (JK) Bugsie Teutell and son EgoBoy of Orange Blossome Motorcycles have made a few lawn ornaments with color engines haven't they? OK remove your fingers!!!

The 83-85 GPZ's came with black motors, and agreed, that stuff is tough.

My late 80's GS650L had black cases.

I use high temp motor paint found at the parts store, but at a recent ride, saw a harley that had the motor painted pink, and it was holding up well. Not impressed with the color, but was very impressed that what looked to be a daily air cooled runner without a whole lot of TLC running esentially "regular" paint on the jugs and such. And it looked to be holding up: wasn't this years paint job, for sure.

I agree with wired's findings, the part about usually using different paint for different motor parts. Gonna try the brush on ceramic from JC Whitney on the pipes one day, see how it holds up.

The "tough" paint that the manufacturers use on the engines is probably a high-temp epoxy of some sort. The coatings are two-component mixes (resin and hardener) and once cured perform very well. Difficult to do at home unless you are familiar with spray application and have the right equipment.

Some may use a powder coat system as well. Anything you buy off the shelf in a can will never match the durability and toughness of an epoxy.

Mandrake

I went for the black cases/polished covers look too on the 650 engine I´m rebuilding, using PJ1 wrinkle paint.

I took the engine completely apart and thoroughly cleaned everything before I glass bead blasted it - contrary to popular belief bead blasting won´t remove grease and dirt, parts need to be clean first. And don´t even think about blasting without disassembling, the media goes everywhere - even though I blocked all passages and bolt holes before blasting I had to remove the worst media residues with compressed air, then wash the parts twice with soapy water and twice with a pressure washer, drying them with compressed air between each wash before I was satisfied there was no residue left.

Before painting I set the engine up as an empty shell (painted the oil pan seperately), heated it thouroughly with an electric fan heater, sprayed it down with paint thinner for a final degrease (don´t touch it anymore at this point), painted it twice with PJ1 wrinkle paint (paint gun, not rattle can), let it sit for a day, then baked it in the oven (not the one I cook in) at app. 200F for a good hour to cure the paint.

Can´t say much about heat dissipation or durability as it´s not assembled yet (pics are just the empty shells set up for a photo), but the finish seems very hard, took quite a bit of filing/sanding work to remove the paint from the head fin edges. Doesn´t look too bad either if I may say so myself:

Another:

And how it looked when I started - as you can see the engine (79 SR) was already black, not sure if it was stock paint but it wasn´t easy to remove: