RRussellTx - 1974 Commando 850 Project

Vapor blasting is a very effective cleanup and leaves an attractive finished appearance. The Amals were Vpr. blasted then the manifolds, bowls and caps went out for powder coating along with a lot of other parts...much like your project appears.
Once I got a look at the finished results of vapor blasting I ended up taking lot of parts to my local shop. I found the cost very forgiving from the perspective of time spent on cleanup and the need for clean fitting/sealing surfaces.
The guys in the shop would come out to the truck and help me haul boxes inside, we were on a first name basis quickly.

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Keep the peace in the house. An outdoor gas grille works well to heat case to remove bearings. With a light tap they should drop right out on their own if case is upside down. Put the new ones in the freezer before hand and install while the case is hot.
 
I like worst nightmares. I bought Molnar barrels with a stock 750 bore and stock diameter MAP Cycle 750 pistons and long rods, measured the ring gap and tossed the pistons in. Engine would have blown up by now if they didn't work. I never bothered to measure the pistons or bores. Well maybe I did, but didn't write it down anywhere. Living on the edge
 
GP, no problem. I always do what you do, have the machinist estimate what it will take to clean things up. Then I get the pistons and have them measure and bore and hone to tolerance I want. I always used .0045 with the Tiawan JCC type pistons. Even if the bore and hone has been done the pistons and bores can still be requested to be measured. If the tolerance is too tight some additional honing should correct it. If too loose will probably have to live with it. A little bit bigger shouldn't be a problem on a street bike that gets typical vintage bike mileage. I'd be mainly concerned about them being too tight.
 
grandpaul said:
Unless I missed something, I would never bore cylinders without the pistons and rings on hand to measure first.

Trying to find set of pistons within a few thousands DIFFERENCE from a different brand, could/should prove to be your worst nightmare...
Click to expand...
Understood, both sets will be matched to pistons when they are done.
 
htown16 said:
Keep the peace in the house. An outdoor gas grille works well to heat case to remove bearings. With a light tap they should drop right out on their own if case is upside down. Put the new ones in the freezer before hand and install while the case is hot.
Click to expand...
I have my little powder coating oven in my detached garage that will do the trick. I only used the house oven once…
 
One useful tip that I don't think anyone has mentioned so far is the "Tools you have made" thread. Some very useful stuff there, including some good suggestions on removing the carb manifold Allen screws.
 
More devil's advocate gibberish from me:

If the crank, rods, and cam aren't back in the cases yet, there is still time to burn more money on the engine than you ever wanted too. The long rods and light weight pistons usually result in a better performing and smoother running engine. Only reason they would not is if an assembly or aftermarket machining error was made. Of those that have done it, I doubt they wish they had not. The JSM valve train parts are nice as well. A JS1 cam might be a good addition. I like the JS2 and consider it to be a good street cam, but it might be a little more than most have any use for. I don't know how somebody with a Cobra wouldn't appreciate some more lift though. :) If working with a JS Motorsports cam and valve train parts you can save a couple of dollars and a substantial chunk of installation time if you have your stock tappets radiused.
 
Big D cycles called and I can pick up the heads and cylinders on Tuesday.

Also, I received the Gearbox bits from Greg so I just needed to get things cleaned up.

I finished the Vapor Blaster setup and started cleaning parts.
Pretty happy so far but I feel like I need to do something to seal the aluminum.

Do you guys ever seal the aluminum with anything?
I'm thinking about using Sharkhide to seal it up...

Vapor Blaster.jpeg

Vapor Blaster.jpeg

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sharkhide.jpeg

sharkhide.jpeg

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Gear Box.jpeg

Gear Box.jpeg

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Gear Box 3.jpeg

Gear Box 3.jpeg

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Gear Box 2.jpeg

Gear Box 2.jpeg

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Never heard of sharkhide protectant, thanks for the tip, another reason I love this forum so much :) I did have some shark skin boots before, but that doesn't really count, does it :) Good pair of boots but salt stains were troublesome.
 
cjandme said:
Never heard of sharkhide protectant, thanks for the tip, another reason I love this forum so much :) I did have some shark skin boots before, but that doesn't really count, does it :) Good pair of boots but salt stains were troublesome.
Click to expand...
I have tried a variety of clear coats over the years on different metals.
Never Shark Skin though.
Sooner or later damn near every coating applied yellowed or strayed away from clear. Cracking or migrating from heat or micro bubbling or some other shift from original. Heat or sunlight or simple oxidation from age seem to be the cause.

The one coating that did hold up, and its been 9 years, was a clear powder coat. The aluminum manifold below was coated before assembly began. After 10 years and a whole lot of heat cycles it is still "clear" as in no discoloration.
It also helps smooth out the textured surface of the aluminum for easier wipe off/cleanup if that is something you adhere to.

RRussellTx - 1974 Commando 850 Project
RRussellTx - 1974 Commando 850 Project
 
I use a product called Shine Seal - formerly called Zoop . Ceramic sealant that you simply wipe on for matte finishes ( cases, etc . )
And wipe on/ buff out with included polish for shiny stuff - polished covers , etc . Expensive but foolproof easy application.
I am the world’s biggest skeptic when it comes to snake oil remedies but this stuff works .
RRussellTx - 1974 Commando 850 Project

My ES 2 done with Shine Seal 13+ years ago and I live at the seashore in the northeast- the corrosion capital of the universe.
 
Apparently, there is another uncle and another Norton...

It was pretty cool hanging out with these guys growing up 50-ish years ago.
I'm the little twerp up front - we were camping out and riding dirt bikes all weekend.
I was the coolest kid in elementary school when they picked me up with a truck full of dirt bikes towing a camper.

Another Norton.jpeg

Another Norton.jpeg

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Another Norton2.jpeg

Another Norton2.jpeg

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FlyingP.jpg

FlyingP.jpg

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I have the gearbox apart and almost everything is cleaned up and ready to go back together.
Are the layshaft 3rd, and mainshaft 2nd supposed to be a sliding fit?

Mine are not.

I have tried several things to try to loosen them up but no love.

Any suggestions?
 
As I recall those are both a sliding fit on the shaft and in the gear. Are they new replacement bushings? I replaced the bronze bushings in one rebuild with new and they were tight, so I gently relieved them with some fine grit emery paper. A better option might be to have them reamed at least the inner clearance.
 

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