Painting Engine Cooling Fins

Ok, so I have read tons of articles browsing the internet about how to make that XJ650 Maxim engine shine like new. I've seen YouTube videos where the 82 Maxim engine looks like brand new. The general advise is to "just take a scotch brite pad and some SimpleGreen and get to cleaning and it will look just like new". I've done that for hours and my engine just looks a little better. I have also noticed that when the 1982 Yamaha XJ650 was new the lower half of the engine cooling fins were actually painted black. I didn't notice that until I had scrubbed for hours trying to get what I thought was old remnants of grease off the lower half of my engine. Now that I have the lower half cleaned my question finally is..........What type and color of paint did they originally paint the engine cooling fins (top half)? I noticed that while scrubbing the living daylights outta the top half, there is a grey or silver colored paint on it. Some of the XJ650 restored pics I have seen on YouTube or whereever, the engines had to have been repainted using this paint. There is no way they cleaned them that good. I have used a dremel buffer, chrome cleaner, simple green with scotch brite pads, 300 grit sand paper then electric buffer with polish.....it dont look like new at all. Any help would be appreciated.

 

Great topic. My 650 sat outside for years with the previous owner and has that 'oxidized' look to it. I tried the scotch pads and Tide. Then applied Nevr-dull. What I got was a shiny, less-oxidized look, but certainly not like new. Let's see what the experts have to say.

 

I will recommend PJ1 Case Black, it works well and is a beautiful match for the stock color.

 

Thanks Robert. Where would a guy get that particular paint and also how about the grey or silver paint that is on the upper half cooling fins. At first I thought it was just the silver of the aluminum but after cleaning and wire brushing (not recommended I might add) it turns out to be some silver colored paint which I am sure is a high heat paint from the factory. Thanks again Robert!

 

What model and year bike do you have? Not ALL XJs had painted heads (early ones did) but they almost all had painted cylinder blocks, either silver or black. You've discovered something not a lot of people notice; in fact, the UPPER crankcase halves on the "natural" engined bikes are painted silver too, only the lower CC is truly "natural."

The only way to get the raw aluminum castings really clean to their pores is soda blasting.

Robert's recommendation is good for the lower cases that were originally black; I use Duplicolor high-temp (500* not VHT header paint) Low-Gloss black for the jugs and valve cover. Haven't repainted a head yet; my Seca 650 head was originally black but it's SO flaked off I may just blast it nekkid and leave it.

Check with chacal (XJ4Ever) on the silver for the cases/jugs I know he and I discussed it I don't know what he found. The original stuff is so tough most people don't know it's paint.

 

I have a 1982 Yamaha XJ650 Maxim. I am quite certain that the cylinder blocks were painted black even though when I bought the bike you could not really tell if they were painted or not. This is the first time I have owned a Yamaha so at the time I had no clue that this particular bike had the lower half of the engine or cylinder heads painted black while the upper part had been painted silver (factory silver). I will try to include pics of the right and left side. The left side I have cleaned and right side needs more work. I have heard of this soda blasting of the engine or bead blasting of these parts. I have also learned that you cannot paint the heat resistant paint over the existing factory paint as the engine might overheat. They also say if you paint the lower half black to make sure you sand the paint off the very edges of the fins so they will cool properly. I've been doing alot of research about this painting the engine thing but can't find any information about this silver paint that will match or come close to the factory silver they were painted with..I really appreciate the replies. Here are the pics as links;
* Notice on the 2nd and 4th pictures- You can see the remnants of the black factory paint on the lower fins that I mistakingly thought was just grease or grime.
http://i148.photobucket.com/albums/s40/ ... CF0094.jpg
http://i148.photobucket.com/albums/s40/ ... CF0095.jpg
http://i148.photobucket.com/albums/s40/ ... CF0114.jpg
http://i148.photobucket.com/albums/s40/ ... CF0097.jpg

 

Hb, a 1982 XJ650 Maxim would have used a black valvecover, silver painted heads, jugs, and engine cases (engine componets, besides the valvecover, are all silver).

HIGH-HEAT PAINT PRODUCTS: Engine Cases, Covers, Final Drive, and Brakes:


How Hot is Hot?:

The following information was measured on a stock, un-modified XJ650 YICS engine, with the air temperature between 60- to 70-F. Modified engines, engine tune conditions, different air temperatures and humidity levels, etc. will affect these readings up or down.

Using our HCP9959 Digital Infrared Heat Thermometer, we verify that the cylinders and the valve cover are the hottest part of the engine, with the front of the cylinder jugs (exhaust port side) reaching almost 390-F during and immediately after spirited riding, while the intake side of the cylinders were consistently 50-degrees cooler (350-F). Cylinder heads, surprisingly, remain much cooler, just barely breaking the 280-F mark.

Engine upper case and engine side covers vary in their readings depending on which cover and where on the engine case the reading is taken, but in all cases are substantially cooler than the cylinder head, valvecover, or jugs.

Brake rotors were measured at 300-F or more after 10 consecutive maximum-force braking events from 50mph. Calipers were approximately 50-F cooler.

Rear final drive units are like refrigerators, and were never measured at over 140-F.




Upper and Lower Main Engine Cases:

Most XJ engines feature unpainted, bare natural aluminum finish on the lower (bottom) engine case, and a satin silver metallic painted upper engine case----yes, your upper engine case was painted (we've seen a few exceptions to this situation on some original models, and don't know why, but we'll say that 99% of all original engines are painted). Although most painted engine parts were not originally clear-coated, but we will recommend that you do apply a thin coat of clear to help protect the paint against fuel, oil, and chemical spills.

Other models, such as the XJ650 and XJ750 Midnight Maxims, XJ650RJ Seca and XJ650 Turbo models, 1986 XJ700 air-cooled models, all XJ700-X models, 1983 XJ750 Seca, and the XJ900RK models have gloss-black painted upper and lower engine cases and engine side covers, again without any clear coat originally (but recommended for restoration purposes).

On all models, the engine oil pan ("sump") was always left un-painted, and we recommend that you do the same.


Typical Coverage: an upper engine case will require a minimum of 2-3 spray cans, while the addition of the lower engine case will require another 1-2 cans. Coverage may vary depending on the size and condition of the parts being painted, as well as application techniques.




Engine Side Covers:

Most models have highly machine-polished engine side covers (generator cover, shifter and clutch case covers, small round crankshaft end covers) which were then clear-coated from the factory.

For these models, you can use one of our metal-parts paint strippers to strip away the clear coat, progressively sand with 600-, 800-, 1200-, 1600-, and then 2000-grit finishing papers, and then machine-buff to restore their original mirror-like, almost-chromed appearance (yes, it requires as much effort as it sounds!). Of course, you will then want to clear-coat them again with one of our high-heat clear coat products.

Other models feature the Code 58 Intense Gloss Black painted side covers, which can be stripped and then repainted with the regular high-heat engine paint. Once again, although not originally clear-coated from the factory, we recommend the use of a thin coat of clear for protective purposes.

The XJ650 Turbo and all Midnight Maxim models feature a thin, gold-painted relief ring or Y A M A H A lettering on some of the side covers. We offer a small vial of "touch-up" paint in the original Code 8L Nebular Gold color to allow you to easily refinish those features.


Typical Coverage: the smaller engine side covers (crankshaft end covers and generator covers) can all be painted with one spray can; the larger covers (shifter and clutch covers) will require 1 spray can per cover. Coverage may vary depending on the size and condition of the parts being painted, as well as application techniques.




Cylinder Heads and Cylinder Jugs:

On the top end of the engine, most XJ engines feature the Code 162 Satin Silver Metallic flat metallic painted cylinder jugs and cylinder heads, with Code 98 LGB low-gloss black or Code 33 Competition Yamaha Black semi-gloss black cylinder head valve covers, while all 1981 XJ550 models, and the 1981 and 1983 (but not the 1982 model!) XJ750 Seca models featured un-painted, machine-polished and clear-coated valvecovers.

Other models are equipped with Code 58 Intense Gloss Black painted cylinder heads, cylinder jugs, or both. On models with black-painted heads or jugs, the edges of the fins may or may not be painted black also; if not, they have a natural cast aluminum look to them.

Some later model (1983-later) model engines may have come with un-painted heads and jugs.

Once again, although not originally used, we strongly recommend a high-temp clear-coat be used over all painted surfaces for protection.


NOTE: we also offer both a Code 98 LGB low-gloss black and Code R4 Flat Black engine paint for those people who wish to "soften" the appearance, or to tone-down the high-gloss black with an under- or top-coat of one of the lower-gloss black finishes. Some people find the visual contrast between the high-gloss and lower-gloss black finishes between adjoining components (such as painting the head and the engine case gloss black, but with a satin-blacked finish on the cylinder jugs) to be more visually striking.

 

I really appreciate all the information you have just listed.......That is more info than I could find while browsing for days. And it is specifically for the Yamaha XJ. So you can sand down the clutch cover and other covers that look like chrome and keep using higher and higher grit to get it to look like new.....They almost look like chrome when they were new from the old 1982 Yamaha XJ650 Maxim Advertisement pics I found. Now I'm wanting to take this whole bike apart. I was just gonna use the method of masking off all the other engine parts and spraying it while still on the bike (which I have seen people do from sites I've visited). Looks like it would take longer to tape and mask then to just take the engine out....lol. Thank you very much chacal

 

If all you're worried about are the cooling fins on the sides of the cylinders, you can certainly overspray them with high-heat paint (I used Duplicolor as I mentioned.) That's all I did here:



Then filed/sanded the edges back to silver, like original.

 

When you say overspray, do you mean clean & rough them up a bit then mask everthing else off? Also I would like to ask chacal what is the name of the company that sells the paint he has recommended? Oh and by the way Beautiful job on your Seca bigfitz52. That is a beauty!

 

That's what I did on the cylinders. Used a stiff nylon brush and lacquer thinner to remove as much of the old, flaking paint as could be removed (most of it.) then I masked it off and resprayed it with the Duplicolor.

I'm pretty sure you'll find that chacal sells the paint he is recommending.

Thank you. It was a lot of work but worth every minute of it. (And it's not quite 100% finished yet.)