xs650 Engine Painting Questions

[B Burdine97]

I have my engine all torn apart and I plan on soda blasting and painting parts of it and I have a few questions about the topic. I plan to paint everything black but the cylinder jugs. If I soda blast the jugs and do not paint them, should I hit them with some sort of clear coat to keep them from rusting? Is there even a high temp clear coat available? Next I plan on painting the lower case, both side covers, and the head black, do I need to use high temp paint on these parts of the engine? Finally, do I need to put a clear coat over the parts of the engine that I do paint with high temp paint?
Thanks!

 

[littlebill31]

The engine is aluminum, so it won't rust. It can oxidize though. A clear will work or just keep it clean.
I use high temp on my engine parts and they do make a high temp clear. I use high temp on any engine part.
One thing to remember is surface prep. Don't get lazy with it. Even after it is blasted, clean it thoroughly and use a pre-paint cleaner to insure all the metal is clean of oil, grease, ect. If you don't, you will regret it.

 

[Paul Sutton]

Do these high temperature paints require high temperature to cure as is the case with the exhaust pipe paints?

Thank you.

 

[littlebill31]

I used VHT high temp engine spray paint. No problems with it. I built up the layers though. The paint can run and settle in the fins. Looks like shit if it does and a pain to fix.
Didnt need to cure it, however, I did do it on a nice warm sunny day.

 

[Paul Sutton]

Thank you, so VHT is a tried and tested brand. I used a 500 Degree C tolerant exhaust paint to touch up some rust spots on the muffers and it stayed soft until the bike had a really good run and even then some parts are still soft. I guess I should have bought muffler paint!! My rocker cover needs to be resprayed sometime so it will be a VHT black treatment, the original paint has faded on one side. I will remember your advice regarding thorough cleaning and pre-paint.

 

[Paul Sutton]

I have just been looking at VHT paint curing temperatures. Generally header pipe and manifold temperatures will be sufficient, but if you want to coat colder surfaces then often oven curing is necessary: Examples:

VHT Flameproof (Silica-Cermic Coating):

• Paint must be completely dry before curing
• Heat to 250°F (121°C) for 30 minutes
• Cool for 30 minutes
• Heat to 400°F (204°C) for 30 minutes
• Cool for 30 minutes
• Heat to 650°F (343°C ) for 30 minutes

VHT Engine Metallic and VHT Engine Enamel- looks interesting as the cure temperature is lower:

• Bake at 200°F (93°C) for 20 minutes.
• The inherent heat of engine operation will also accomplish curing.

Hycote VHT Coatings (UK):

At 160 °C Curing Time = 100 minutes
At 190 °C Curing Time = 50 minutes
At 205 °C Curing Time = 30 minutes
At 220 °C Curing Time = 20 minutes
At 230 °C Curing Time = 8 minutes

Hycote could be an issue on the engine casings because they do not get hot enough.
Halfords VHT in the UK is not suited for mufflers so certainly will be a problem on engine casings, barrels and rocker covers may also be an issue???

I conclude that you need to choose a VHT paint that has a suitable cure temperature for the application you need. A few months back I recall someone on this forum measured engine temperatures and this data could be useful in choosing paints but I cannot find the thread. Based on a wet finger I know the head gets above 100 Celcius, but I do not think the engine casings and rocker cover get up to 100 Celsius. The barrels are probably close to 100 Celcius or sligthly over. I am sure the data is out there.

Edit: I meant to say that if the engine is completely striped down then those components coated with VHT paints with the 93 Degree Celcius cure temperatures could be baked in a domestic oven.

 

[Exploding Coffin Emporium]

Tons of high temp engine paints to choose, easy on that one, just good prep required. I'm always a bit suspect with soda blasting, too many little openings and crevices for it to impregnate itself into but that might just be my OCD acting up, plus it's shit on oil stains and rust. I'd clear the jugs, makes sense to give it a little protection.

 

[littlebill31]

The hardtail in my profile media folder has VHT paint. Worked really good.
Im debating my current build engine as I want a little contrast and am not excited about polishing it. I like either polished or painted (correctly), but no dull and dirty, which is the current state of my engine. So much time to remove the shit ass spray paint hack job that I cant even think anout polish right now.

 

[cra-z1]

Take a look at PJ1 engine paint. It does a nice job and ver resilient. I have used it on my Z1900 73 which came black from the factory. It does need to be cured with heat which can be the heat produced only from the engine or you can start thr curing process in an old oven. On the cylinders you can help keep the finish bright by beadblasting clean with a sharper edged material then bead blasting with a larger spec round bead at a lower pressure which will peen the surface and close the pores up.

 

[cra-z1]

You might consider having the cases vapor blasted by a shop who specailizes in the process. The cases should be as clean as they can be. Paint can be a pain if it gets damaged and you may like the look of the clean bare engine. I would not clear the jugs. That 650 you see is going on 7 years since completion and has been riden in the rain several times. True it does not see many miles but it does get ride every year. I just wipe it down(the engine) with a cotton cloth and maybe a little wax when I can

 

[Paul Sutton]

Craz-1, amazing finishes!! Those barrels look so perfect and the XS is exhibition standard. The PJ1 engine paint (500F I am guessing) is a lower temperature paint which is good , and it is available in the UK which is excellent! Now on the XS, what have to sprayed on the barrels, head and rocker cover? Is it the PJ1 Epoxy clear coat? I plan to strip my engine down this Summer so I am getting the planning done now.

Thank you.

 

[B Burdine97]

Thanks for the help guys, craz-1 your engine finishes are spectacular, great work.

 

[B Burdine97]

Craz-1, what is the best way to get jugs to look like the one in your first pic? How do you make everything black but the fins?

 

[Paul Sutton]

Years ago I painted a set of barrels black on an RD250B, I then used fine sandpaper on a foam pad to remove the paint from the fin edges. The bike originally had a sanded pattern on the edges. This sanded appearance is also on my XS650SH.

 

[B Burdine97]

Good to know thanks! Didnt know if someone could use a flappy wheel or like a roloc disk to grind off the paint on the fins, i suppose a sanding block might work best, that way only the paint on the edges of the fins will be removed. Thanks!

 

[cra-z1]

There is nothing on the Xs cases and barrel, that is the bare metal. All covers were polished by me. Like I said check out Vapor blasting. Or someone who is good at dry blasting, then peening the surface with a round bead at lower pressure. I used a dermal to sand the edges.