Yamaha YA-1 Resurrection

[Yamanatic]

Gasket time! I am sure many here probably already do it this way, but just in case it has never come up...
Smaller gaskets are easy; make a tracing and get out the Exacto knife and hole punch, and go to it. But if a big gasket (like a clutch cover) is needed, it can be a real pain to get right. OTC gasket material comes in a roll, which makes no sense because gaskets are flat. Here's a method that usually works first try:

To start, the gasket material is flattened (sort of) using a hot-water soak then laid out on a piece of board with the side-cover on top. Next, several drywall-type screws are ran into the board through the cover's bolt-holes, and tightened down to hold the gasket material firmly sandwiched between the cover and board. Then using a box cutter (my preference), cut around the OD giving the exact shape that looks pro on the edge that will show after installation. 
      
For screw holes (which can be quite deep), a long 6mm drill bit is used, with the angle on the cutting ramps reduced to about 10-degrees to stop he bit from grabbing and tearing the gasket; this minimal angle on the bit is also used for drilling screw holes in plexiglass windscreens without causing stress-cracks or spidering. There was only one hole in the YA-1 gasket, but that's rare. The cover is now un-screwed from the board (by now the gasket has mostly flattened) and the ID is cut. 

A pencil-compass (like those is used to draw drafting circles) is set to the width of the gasket face, and ran around the entire OD to mark the inner margin and give a point of reference. For screw bosses the 'dirty-finger' method works well; with the cover pointing up and the gasket blank held in position with the case screws, press very firmly around the inside curves of the boss edges and your fingers will leave a 'dirt' mark to trace around with the knife. To cut the ID, the box-knife was used except for the Exacto knife for tight curves - curved drafting protractors make excellent cutting guides. And that's it!

Next, the cover gets a trip to the wet-slurry blaster to erase the battery-acid etched cover (wet leaves a very original finish), and the kicker and shifter get re-plated. The pure (99.44%) zinc anodes arrive in a few days for the home electroplating process on the levers. Nickel is too 'gold,' and does not look like the bright cadmium used in the day - zinc is almost cad-white when polished.



Warren

[Yamanatic]

The zinc electroplating worked fine using the new (home-brew) salts mix and pure zinc anodes on the kick-start and shift levers; I had a Caswell Copy-Cad kit before but used their 'secret' Caswell zinc alloy anode (used it up) instead of pure Zn.

The chemistry was nothing exotic being a mix of vinegar, Epsom salt, corn-syrup as a brightener to get that cadmium/white look, powdered zinc-sulphate, and distilled water.
I have a low-voltage plating transformer, but it only goes down to 2V - the surface area of the levers calculated to 1.5V so I used the primary windings from a Yamaha coil as a 0.5V resistor; otherwise the zinc plating goes on too fast and leaves a 'sandy' surface that does not polish out well.
Turning the work every 10 minutes, it took a total of 30 minutes per lever. Polishing was done with 000 steel-wool. Engine electrics are next.


 
Warren

[Simmons1]

That's pretty awesome

[Yamanatic]

Thanks for that!
Had to refresh 3 times to get the above 3 pics to show. Hope I have it now...
Warren

[SoCal250]

Very nice Warren. You're a mechanic and a chemist!

[Twill864]

Care to share the homebrew formula and setup? I really need to get a power supply and go to town. Did you put the levers in a vibrator with sand media before hand?

[Yamanatic]

Hi Tw,
Here's the ingredients for about a gallon of Zinc electroplating 'Salts,' done in Metric (easiest for me):
 
1 - 3 Liters Distilled Water 
2 - 0.2 Liters White (cheap) Vinegar
3 - 0.12 Liters Karo Syrup (or about 120 Grams pure cane sugar) as a whitener/brightener 
4 - 300 Grams Epsom Salt
5 - 100 Grams Zinc Sulfate Monohydrate (powder); super cheap. ZnSO4 provides the zinc ions in solution to facilitate the transfer of the Zinc Anode to the Work.
6 - Pure Zinc Anode strips or sheet; again cheap, just be sure it's 99%+ pure.

Worry not if measurements are not 100% perfect; a Ratio-Rite and Food Scale are plenty close. Give the mixture about 24 hours for everything to completely dissolve before using. I mixed mine up in a 1-Gallon capped jug, shook it every few hours, and used it the next day - it doesn't pressurize if you leave the cap on.  

Zinc Sulfate Monohydrate Powder - 35.5% Zn - 2 Pounds | eBay

12 Pcs Pure Zinc Anode Sheet (99.995% Pure) for Plating and Zinc... | eBay

7 - Power Supply:
No need for a plating transformer for smalls like the YA-1 levers; dry-cell 1.5V batteries - AA/C/D work. I used a parallel type flashlight battery holder with 4 AA's before buying a used electroplating transformer - 2V~10V at 3 amps was needed for bigger pieces like rims and handlebars. Anodes go to the + side, Work to the - side. I use 2 Anodes (one on either side of the work), or you can turn the work around at 5 or 10 minute intervals to get an even plate - just  be sure to expose all surfaces to the Anode(s).  There is a formula for how much voltage to use for a given surface area but I go seat-of-the-pants. Too much voltage and the plating will come out grainy, thick, and gray, and not enough voltage gives a thin, 'rainbowish' colored finish that takes forever. When you get it right it takes about 30 minutes, and leaves a nice, smooth, bright finish; expect bubbles to form on the work after a few minutes, and a light foam (sometimes) on the surface of the bath around the work. No bubbles usually means more voltage is needed, and too much bubbling (white opaque foam) means reduction. 1.5V to 2V does most everything M/C. Rinse thoroughly in tap water when done. I usually polish the part with 0/00 Steel Wool for more shine. 

I used Fine Glass Beads in a blaster to prep the levers; rock/vibratory tumblers work great too. Wipe the work down with 99% alcohol and let it dry before plating - if not, you may leave fingerprints or bare spots in the Zinc. The hangar wire will leave a bare spot where against or too close to the Work too.  

Another addition to the restoration progress, rebuilding the YA-1 Advance Mechanism; it was stuck retarded (I can sympathize), had corrosion, and both advance-springs were missing. Being careful not to over-restore an engine part (good excuse, huh?), I took it apart and spent maybe 15 minutes at the wire-wheel (bench mount with extra-soft bristles) to eliminate the corrosion and rust, a once over with medium steel wool to get the crevasses, then washed and rinsed everything in distilled water. The pieces were staggered along a piece of safety wire hanger and plated all at once using the same setup exactly as for the levers - a piece of masking tape was wound around the pivot shafts on the flyweights to prevent plating. 

The big trick was the springs; all newer Yamaha (and several other's) advance springs were way too large. The YA-1 springs were sandwiched in a space that measured 4mm wide; Back to China =( for a bulk 1 foot length of 3.5mm OD Expansion Spring to make new ones. Luckily Yamaha used the 'down and dirty' method to make the springs and both end loops were just a coil of the spring bent straight out. Hardest part was keeping 4 spring ends hooked up and screwing the tension plate down at the same time. Works fine now!

Warren