Author Topic: Painting engine questions  (Read 4199 times)

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Offline SKOL

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Painting engine questions
« on: April 27, 2016, 04:18:57 AM »
I have a few questions when it comes to painting my engine. I'm going to leave the covers polished, just re-paint the motor a nice silver. The engine is complete torn apart at the momemnt. Should I repaint piece by piece, i.e., tape off the bottom case and paint it, tape off the top and paint it, etc. or just clean everything, soda blast it, and wait until it is all assembled and just tape off the covers? What do you guys think? Anyone had good success either way? Also I've heard mixed reviews about VHT, anyone have any other tried and tested engine paint they use religiously? Thanks

Offline Stev-o

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Re: Painting engine questions
« Reply #1 on: April 27, 2016, 04:50:30 AM »
I've used VHT with good results.  Recently painted my fully assembled K3 motor, and would suggest that to prevent paint damage during assembly, but can do either way.
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Offline 70CB750

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Re: Painting engine questions
« Reply #2 on: April 27, 2016, 04:52:10 AM »
It was done both ways, I prefer to paint it a piece at a time - you can bake the part to harden the paint.
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Offline NobleHops

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Re: Painting engine questions
« Reply #3 on: April 27, 2016, 07:03:30 AM »
It was done both ways, I prefer to paint it a piece at a time - you can bake the part to harden the paint.

Agree with all - I've had great success with VHT, but you MUST bake it for durability. If however you don't want to worry about it, send it to me and I'll vapor blast it :-)
Nils Menten * Tucson, Arizona, USA

I have a motorcycle problem.

My build thread: NobleHops makes a 400F pretty for his wife: http://forums.sohc4.net/index.php?topic=131210.0

Offline NobleHops

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Re: Painting engine questions
« Reply #4 on: April 27, 2016, 07:05:06 AM »
Here's an excellent how-to on the engine painting process:

http://www.cbxclub.com/forum/viewforum.php?f=27
Nils Menten * Tucson, Arizona, USA

I have a motorcycle problem.

My build thread: NobleHops makes a 400F pretty for his wife: http://forums.sohc4.net/index.php?topic=131210.0

Offline flybox1

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Re: Painting engine questions
« Reply #5 on: April 27, 2016, 07:11:22 AM »
It was done both ways, I prefer to paint it a piece at a time - you can bake the part to harden the paint.
+1
Paint and bake individually.
Its all in the prep, for rattle can paint to last.  blast, pressure wash, acetone wipe down.
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

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Offline NobleHops

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Re: Painting engine questions
« Reply #6 on: April 27, 2016, 09:34:27 AM »
It was done both ways, I prefer to paint it a piece at a time - you can bake the part to harden the paint.
+1
Paint and bake individually.
Its all in the prep, for rattle can paint to last.  blast, pressure wash, acetone wipe down.

I've done this set of steps, worked great, but some kind of phosphoric acid etch (alodine, alumaprep) is a skosh better yet. Wear gloves while cleaning, keep your grubby fingerprints off of the parts. :-)
Nils Menten * Tucson, Arizona, USA

I have a motorcycle problem.

My build thread: NobleHops makes a 400F pretty for his wife: http://forums.sohc4.net/index.php?topic=131210.0

Offline przjohn

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Re: Painting engine questions
« Reply #7 on: April 27, 2016, 10:07:03 AM »
Another vote for painting by pieces and baking. I have had great luck with VHT paint color "Universal Aluminum" Baking is a very important step and should not be omitted.
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Offline SKOL

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Re: Painting engine questions
« Reply #8 on: April 27, 2016, 10:19:37 AM »
It was done both ways, I prefer to paint it a piece at a time - you can bake the part to harden the paint.
+1
Paint and bake individually.
Its all in the prep, for rattle can paint to last.  blast, pressure wash, acetone wipe down.

I've done this set of steps, worked great, but some kind of phosphoric acid etch (alodine, alumaprep) is a skosh better yet. Wear gloves while cleaning, keep your grubby fingerprints off of the parts. :-)


After blasting, pressure washing, and acetone wipe down. When it comes to getting to cases ready for primer, should I use a soft scotchbrite pad with alodine or alumaprep to etch the cases slightly, or just rub it on? I know I want to make the surface slightly rough for the primer to adhere to nicely.
« Last Edit: April 27, 2016, 10:21:09 AM by nalexandrou »

Offline gtmdriver

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Re: Painting engine questions
« Reply #9 on: April 27, 2016, 11:10:08 AM »
I used POR15 engine enamel on my Moto Guzzi cases.

I painted it almost fully assembled.



Brushing the paint left streaks so I thinned it with White Spirit and sprayed it. No baking needed.

It has been on for 8 years now and is definitely petrol proof.

Offline Ilja

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Re: Painting engine questions
« Reply #10 on: April 27, 2016, 11:15:17 AM »
Just be carefull baking the cylinders. Did it once and all the sleeves came out under the weight of the cylinders during baking. Thats a hone job after reinstalling.
You can also bake it by driving... but I think the paint will be slightly less though.
« Last Edit: April 27, 2016, 11:16:54 AM by Ilja »

Offline flybox1

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Re: Painting engine questions
« Reply #11 on: April 27, 2016, 11:19:31 AM »
It was done both ways, I prefer to paint it a piece at a time - you can bake the part to harden the paint.
+1
Paint and bake individually.
Its all in the prep, for rattle can paint to last.  blast, pressure wash, acetone wipe down.

I've done this set of steps, worked great, but some kind of phosphoric acid etch (alodine, alumaprep) is a skosh better yet. Wear gloves while cleaning, keep your grubby fingerprints off of the parts. :-)


After blasting, pressure washing, and acetone wipe down. When it comes to getting to cases ready for primer, should I use a soft scotchbrite pad with alodine or alumaprep to etch the cases slightly, or just rub it on? I know I want to make the surface slightly rough for the primer to adhere to nicely.
your blasting will give the surface enough texture to hold paint.  I skipped etching and priming..
I used about a dozen rags and 2 qts of acetone to do my whole engine. 
Wiped till all surfaces came clean, then went right to paint.  Baked 30 min @ 250
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
77/78 cool 2 member #3
"Knowledge without mileage equals bullsh!t" - Henry Rollins

"This is my CB. There are many like it, but this one is mine…"

Offline Rocky2010

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Re: Painting engine questions
« Reply #12 on: April 27, 2016, 07:00:21 PM »
Im at the stage of stripping my engine I think I will get it Hydroblasted and leave it with that finish rather than paint the engine with silver paint.
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Offline NobleHops

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Re: Painting engine questions
« Reply #13 on: April 27, 2016, 08:39:32 PM »
Im at the stage of stripping my engine I think I will get it Hydroblasted and leave it with that finish rather than paint the engine with silver paint.

Send you a PM, but in Australia, (Sydney) you should consider Dave Mac - he is excellent at this work and just a great guy.

vapourblasting@yahoo.com.au
« Last Edit: April 27, 2016, 08:42:00 PM by NobleHops »
Nils Menten * Tucson, Arizona, USA

I have a motorcycle problem.

My build thread: NobleHops makes a 400F pretty for his wife: http://forums.sohc4.net/index.php?topic=131210.0

Offline koendd

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Re: Painting engine questions
« Reply #14 on: April 28, 2016, 07:22:51 AM »
Just be carefull baking the cylinders. Did it once and all the sleeves came out under the weight of the cylinders during baking. Thats a hone job after reinstalling.
You can also bake it by driving... but I think the paint will be slightly less though.

you can, but I've had a carb leaking (just forgot to thighten a drain screw on my K2) and dripped overnight on my newly painted engine...

I could peal the paint of.  >:(

Luckily you can repaint it and you won't notice it afterwards. Blends in perfect with allready painted area's...
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Offline NobleHops

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Re: Painting engine questions
« Reply #15 on: April 28, 2016, 09:51:47 AM »
Did you bake this engine? I've spilled gas on mine and no problem.
Nils Menten * Tucson, Arizona, USA

I have a motorcycle problem.

My build thread: NobleHops makes a 400F pretty for his wife: http://forums.sohc4.net/index.php?topic=131210.0

Offline koendd

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Re: Painting engine questions
« Reply #16 on: April 28, 2016, 01:30:22 PM »
nope,

engine ran perfect, just didn't look good...
Couldn't tear it apart just to paint it.

It'll bake while riding, just have to be carefull not to spill gas etc before you can ride a for a while..
1972 cb750K2 brat
1976 cb360
1984 GPZ900R

Offline adamrdiamond

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Re: Painting engine questions
« Reply #17 on: May 11, 2016, 11:06:30 PM »
Did you cover all the screws and bolts before painting or pull them all of?

Offline rocs

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Re: Painting engine questions
« Reply #18 on: May 12, 2016, 04:01:00 AM »
Did you cover all the screws and bolts before painting or pull them all of?

I think i may leave my screws on and paint. Once cured i may take them off and polish them.
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Offline koendd

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Re: Painting engine questions
« Reply #19 on: May 12, 2016, 01:48:19 PM »
yep, don't take them off till after paint.
Just remove and replace/polisch them one by one after the engine is dry ;)
1972 cb750K2 brat
1976 cb360
1984 GPZ900R