SILVER PAINT ON ENGINE & TRANS CASES (2005)

Status
Not open for further replies.
Joined
Jun 14, 2003
Messages
747
Does anyone have information regarding paint on Norton engine and transmission cases?

It appears that later year engine and transmission cases were painted silver by the Norton factory. Have these components always been painted? If not, when did Norton begin painting them? When rebuilding an engine, do any forum members paint their engine cases silver?

Thanks,

Jason
 

ILLF8ED

VIP MEMBER
Joined
Dec 30, 2003
Messages
3,434
Country flag
painted engine cases

Hi Jason,

None of my 750s had painted cases including a late '73. My '74 JPN 850 did have the cases painted, so it's likely Norton did this on the 850s. Someone mentioned a trick for cleaning up cases by spray painting aluminum color then wiping off the excess. I did this a couple of years ago on the JPN and it works very well.
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
18,670
Country flag
Jason,
I know you have asked this question already and haven't had an answer but this is the first I have heard about Norton painting the cases.

I have an 850 MkIII, the date stamp on the headstock gives its date of manufacture as 7/75, the crankcases aren't original but the gearbox casing is, and there's no evidence of any silver paint having been applied to it.
Perhaps others here know more?
Where did you get this information?
 
Joined
Apr 15, 2004
Messages
1,616
Country flag
Mine are bare metal and that's how they're going to stay. Seems like the Amal drip would quickly ruin the paint on the top of the crankcase. Then what do you do?

If you have a Mikuni perhaps that's not as much of an issue, provided you're VERY careful when draining the carbs.

Debby
 
Joined
Sep 4, 2005
Messages
8
silver paint

I bought a '74 850 new. The cases were painted with some kind of silver paint, which became obvious when I took it to the carwash and sprayed degreaser on it. This removed most of the paint.
 
Joined
Oct 9, 2004
Messages
198
I'm not too keen on the raw cases, from an aesthetic standpoint anyway. Good paint's an easier surface to clean oil from too.

SILVER PAINT ON ENGINE & TRANS CASES (2005)


I painted my case-halves with PJ1 Yahama Silver. They'd already been tanked and bead-blasted - so it was only a matter of blasting them with a little carb cleaner, shooting them with a couple of light coats then curing them in the oven - 250deg F for an hour. I did the same with my gearbox.

FWIW, my 1973 case halves were clearly painted silver when they came into my posession. Whether that was done at the factory or later - I can't say.
 
Joined
Dec 5, 2005
Messages
90
Painted cases

Hello all, my 2/74 850 is now stripped, and this bike is a very original 14,000 mile bike, I estimate this is the first time the engine has left the frame. And yes there is some silver paint evident on the gearbox and engine casings, but not the back primary case.
I would expect silver or any other paint applied straight over alloy to not stay on without some form of etch priming.
Unless anyone knows of a self etching silver, it would probably easier to remove what silver is left and stay in the buff, so to speak!
However if a self etch is available, let me know please.

Regards Richard
 
Joined
May 22, 2005
Messages
33
My 850 mk 3 has never had the engine or gearbox removed from the frame ( i have all it's history) when i removed the starter motor this weekend i found silver paint on the crank case beneath it, and looking closely i can now see other patches of silver paint on various parts of the crank cases.
I believe this must have been done at the factory, after all who would remove the starter to paint underneath it?
hope this helps.
 

WMW

VIP MEMBER
Joined
Dec 25, 2004
Messages
40
Country flag
Case/Tranny paint

From Old Britts website: (http://www.oldbritts.com/ob_start.html)



Painting the Crank Cases


Summary:

This article covers the procedure we use to paint the Commando crank cases. The Commando crank cases came painted from the factory, and when you rebuild your engine it is nice to make the crank cases look as original as possible.

We have found a close a match to the original paint in the PJ1 Yamaha Metallic Silver Case Paint, (our part # 78-600001, $8.20) This is a 500ºF paint and is so close match that you have a hard time seeing where you have painted and not painted on a walnut blasted case.




Preparations for Painting:

After splitting the cases and removing the crank bearings (See Crank Case Bearing Removal for a simple way to remove the crank case bearings), thoroughly clean the case halves using a strong solvent like PJ1 Contact Cleaner (part number 78-300001, $6.50) After cleaning the cases, it is recommended to have the cases bead blasted with walnut shells to remove all the old paint. If bead blasting is not an option, try a stiff scrub brush or a wire brush to rough up the surfaces to be painted making sure you avoid any mating surface like where the two halves fit together.

Make sure that all dry fittings of the cam and crank have been completed and the crank bearings are installed in the cases before painting the cases. Just prior to taping off the cases clean the cases again with PJ1.




Using a couple of case bolts, bolt the two halves together.
In this picture an old aluminum base gasket was tape off with masking tape to make a blanking plate and placed over the top opening. You can use a base gasket as a pattern and cut out of cardboard a blanking plate. Use three of the cylinder studs to position the blanking plate. Tape the studs to prevent them from being painted and they will also serve as good places to pick up the newly painted cases.
Using about three of the timing cover screws, fasten the timing cover to the case and tape it off.
Tape off the drive side, primary case mating surface.
Place the tach drive housing in the case and tape it off.
Tape off the mating surface where the oil junction block fastens to the case.
Tape off the breather pipe.
insert the drain plug and/or the sump plug and tape them off.
Tape off any other openings or things that you do not want to get painted.

Follow the instructions on the paint can and apply a couple of light coats of paint. We find that placing the cases with the top down and painting the bottom first works for us. After the bottom second coat is fairly dry, turn the cases over and finish painting the top.

The paint should be applied at temperatures above 70ºF and in a well ventilated place. If you are doing this in the winter and do not want to paint in your shop, we found that as long as the temperature is not below 40ºF you can get the cases good and warm in your shop, take them outside to a previously prepared painting area, quickly paint the cases and take them back into the shop to dry between each coat.




This is a picture of the cases after painting


Painting the Crank Cases
Any price mentioned in this article is current as of 12/08/05.

Summary:

This article covers the procedure we use to paint the Commando crank cases. The Commando crank cases came painted from the factory, and when you rebuild your engine it is nice to make the crank cases look as original as possible.

We have found a close a match to the original paint in the PJ1 Yamaha Metallic Silver Case Paint, (our part # 78-600001, $8.20) This is a 500ºF paint and is so close match that you have a hard time seeing where you have painted and not painted on a walnut blasted case.




Preparations for Painting:

After splitting the cases and removing the crank bearings (See Crank Case Bearing Removal for a simple way to remove the crank case bearings), thoroughly clean the case halves using a strong solvent like PJ1 Contact Cleaner (part number 78-300001, $6.50) After cleaning the cases, it is recommended to have the cases bead blasted with walnut shells to remove all the old paint. If bead blasting is not an option, try a stiff scrub brush or a wire brush to rough up the surfaces to be painted making sure you avoid any mating surface like where the two halves fit together.

Make sure that all dry fittings of the cam and crank have been completed and the crank bearings are installed in the cases before painting the cases. Just prior to taping off the cases clean the cases again with PJ1.




Using a couple of case bolts, bolt the two halves together.
In this picture an old aluminum base gasket was tape off with masking tape to make a blanking plate and placed over the top opening. You can use a base gasket as a pattern and cut out of cardboard a blanking plate. Use three of the cylinder studs to position the blanking plate. Tape the studs to prevent them from being painted and they will also serve as good places to pick up the newly painted cases.
Using about three of the timing cover screws, fasten the timing cover to the case and tape it off.
Tape off the drive side, primary case mating surface.
Place the tach drive housing in the case and tape it off.
Tape off the mating surface where the oil junction block fastens to the case.
Tape off the breather pipe.
insert the drain plug and/or the sump plug and tape them off.
Tape off any other openings or things that you do not want to get painted.

Follow the instructions on the paint can and apply a couple of light coats of paint. We find that placing the cases with the top down and painting the bottom first works for us. After the bottom second coat is fairly dry, turn the cases over and finish painting the top.

The paint should be applied at temperatures above 70ºF and in a well ventilated place. If you are doing this in the winter and do not want to paint in your shop, we found that as long as the temperature is not below 40ºF you can get the cases good and warm in your shop, take them outside to a previously prepared painting area, quickly paint the cases and take them back into the shop to dry between each coat.




This is a picture of the cases after painting
 
Joined
Jun 14, 2003
Messages
747
Thanks to all who responded to my silver paint question. So, Norton did indeed paint their engine and transmission cases. Perhaps they were copying the Japanese; weren’t the early 750 Honda engine cases painted silver?

Jason
 

L.A.B.

Moderator
VIP MEMBER
Joined
Nov 20, 2004
Messages
18,670
Country flag
The postings here prompted me to have another look at my own bike, but this time with an inspection lamp instead of just daylight, and, looking around the area of the sump strainer I found-SILVER PAINT!! Yes there's definitely traces of a thin layer there on that part of engine cases (which aren't original) although I still didn't see any on the gearbox casing.[Edit: There are traces of silver paint on the underside of the gearbox as well)

Strange it has never been mentioned (as far as I know) in any book-like Roy Bacon's 'Norton Twin Restoration' etc.

My apologies for doubting you Jason!
 
Joined
Jun 14, 2003
Messages
747
No apologies necessary L.A.B.!

New Norton discoveries are fun and I’m happy we got to the bottom of this somewhat controversial issue.

Jason
 
Joined
Dec 5, 2005
Messages
64
Silver paint on Nortons

Did the painting of the engine cases by the Norton factoy also extend to painting the cylinder head silver?
 

concours

VIP MEMBER
Joined
Dec 29, 2011
Messages
6,045
Country flag
Ancient thread, has anyone found better/different/more original paint methods? My '74 is painted, 1/2 of it is gone.
 

Brooking 850

VIP MEMBER
Joined
Oct 3, 2011
Messages
1,595
Country flag
Vapour blasting the cases gives the same effect as painting and doesnt mark as easy or become patchy using cleaners and solvents
I have just had mine done
Regards Mike
 
Last edited:
Joined
Oct 15, 2006
Messages
33
At the risk of becoming Johnny One Note regarding coatings, the best coating for non-decorative surfaces like engine/gearbox cases is Gun Kote (or similar Duracote, or Cericote) thin film system spray/cure system. Regarding engine/trans it only applies to complete disassembly since it requires blasting prep and heat curing.

Any non-coated approach for aluminum will ultimately absorb oil and dirt into the metal pores. Paint systems are (ultimately) affected by solvents and they are easily scratched. Powder coatings are problematic wherever you have joints because of the coating thickness. And both paints and powder coating are insulators and do not transfer heat well.

Gun Kote type thin film coatings are generally very thin (<= .001", can be increased with additional coats before curing) and teflon/moly based. They transfer heat well and produce a slippery surface that sheds dirt and is (after 300 degree cure) unaffected by solvents. It has excellent salt spray corrosion test performance and produces a very hard coating (>9H pencil hardness test for coatings - highest level). Because it is so thin it is unaffected at attachment points. It is available in a number of colors. Obviously, the primary use is aftermarket & high end firearms, but also m/c, auto and industrial. Here are some firearm related videos on durability ,

Dry film coatings require a sandblasted surface (120 grit, NOT bead blasted which peens rather than cuts the metal surface. I have also sanded aluminum sheet to create a brush finish in lieu of sandblasting) and 300 degree oven cure for 1 hr. Prior to cure they can be removed with solvent. After cure coating must be sandblasted to remove. I now use a HF blast gun with a powder hopper (had a small HF cabinet but sold). Blast into plastic garbage bag in drive to collect most of the powder. Wear goggles and mask. Blasting process is pretty quick with smaller parts.

Areas I have used Gun Kote (see photos):

Engine crankcase
Engine cylinders
Cylinder head
Gearbox housing
Engine/trans subframe
ISO housings
Primary drive (non polished surfaces inside & out)
Fork yokes
Oil tank
Main & Side Stands
Rear brushed aluminum bulkhead
3 pt rod arm ISO locating system brackets
Various other brackets

All of these components were coated over 10 years ago.
https://1drv.ms/f/s!Ajp0LHBjgmfvqgzPqT5UV-VCxq-7

The stuff just works. Well. https://www.kgcoatings.com/
Dave Winship
 
Last edited by a moderator:

batrider

VIP MEMBER
Joined
Aug 9, 2008
Messages
2,294
Country flag
Spraying it on makes too heavy a coat and just looks wrong. Spray a shop rag then wipe it on. It should be a very thin coat.
 
Joined
May 28, 2003
Messages
2,591
Country flag
I'll give it a go. Thank you.
Hey Bob
To bad I didn't hear about this earlier. I could have shown you my combat bottom end on the engine stand 2 feet behind you during our web cam profiling exercise. In the middle of the shop I have Bill Barbour and Wayne McDonald's head that I walnut blasted prep for my silver/aluminum wash (paint). Hard to tell it is painted. Been painting them since the late 80's.It's easier to do... than convince people that it was done at the factory originally.
 
Status
Not open for further replies.
Top