Yamaha YDS3 Review: Reader Resto

Date 28.10.2012

Presented by
  • Motorcycle Trader

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This restoration was inspired by the memory of the sound of my friend Mike’s Yamaha YDS3, a memory that has stayed with me vividly for 43 years. Back in the day it was music to my ears to hear his howling Yamaha from a couple of miles away as he headed toward our family farm in Christchurch, NZ. Finally, one night, the memory prompted me to search the internet for a YDS3 of my own – amazingly there was one on eBay, in Kalgoorlie, WA.

Because restoring a basket-case classic can be a real challenge, a successful result is immensely satisfying. That was certainly the case for me with this 1964 Yamaha YDS3. Buying a trailer-load of parts, particularly sight unseen as I did, is not advisable unless you are very patient and prepared to do an incredible amount of work. Of course, you could send out all the work, but I chose to do as much as possible myself.

THE WEB IS MY FRIEND

At least one part of the project was a bit easier than I expected – doing this restoration, my first in 12 years, showed me that the internet now makes obtaining information and parts simpler.

Restoring a complete bike would have been fairly straightforward compared to what arrived at my place. It appeared to be enough parts to build about one-and-a-half YDS3s. Fortunately a factory parts manual was included. It’s an almost essential item for procuring the correct parts and then knowing where to put them. Also included were letters dated 1994 where a previous owner who intended on restoring the Yamaha had written to NZ and the USA looking for items like sidepanels and badges. They were hard to find in ’94 but as in said earlier, the internet makes life a lot easier. I have managed to find everything, with parts sourced from NZ, USA, Canada, UK and Holland. Most parts were NOS (new old stock) but where they weren’t available I opted for second-hand parts.

Overall I have found most suppliers to be very good although some reproduction rubber parts are not brilliant, so take care in sourcing those.

DOING THE JOB

Buying a bike in many pieces it’s difficult to know exactly where to start. My first move was to separate the major parts and then get on with the cleaning, inspection, repair or replacement processes. My trusty old Myford lathe (the same as Burt Munro’s) was invaluable in making many special tools for dismantlimg parts without inflicting further damage. Often the same tools were used for assembly. Overhauling the rear shocks for example, was much easier after I made some specific tools.

Once I stripped down the engine I was greeted by a depressing sight. The Autolube oil pump had some of the smallest parts in the whole bike. Little springs and plungers were hard to find when they ended up on the floor many times. The pressed-together crank assembly and barrels went to engine rebuilder Graeme Williams at Motorcycle Engineering, Somerville, Victoria. Sure enough, it needed crank pins, bearings, con-rods and pistons. Crank pins and rods were very hard to find but were eventually sourced from the US and Canada. The centre rubber oil seal between the cylinders was replaced with a labyrinth seal which was a later improvement. The modification bulletin showed an O-ring around the labyrinth seal but all I could see was a roughly formed hollow. I calculated a suitable Viton O-ring size and machined a groove to suit. I repaired one broken cast cylinder fin by cutting an old broken cylinder then heating the lot in a pottery kiln before bronzing it in place. The welded cylinder was cooled slowly overnight in the kiln, then the cylinders were bored to suit oversized pistons. The barrels were sprayed with high-temp paint and baked in the kitchen oven. During winter, while watching the MotoGP on TV and polishing alloy parts, baffles and exhaust pipes were stuck in the wood burner to remove oil residue and carbon build-up prior to chrome plating.

On inspection the five-speed gearbox only contained nine gears – obviously someone had been there before me. With some gears and shafts being badly damaged, I sourced a used gearbox from US and found it was in excellent condition. After fabricating some damaged alloy engine case parts and jigs they were welded and the engine started to go together. I machined four stand-off feet utilising 6mm threads and was then able to securely support one crankcase half at a time. This made assembling the gearbox, crankshaft assembly and second crankcase half relatively easy. The con-rod openings in the crankcases are very tight, so special care is needed. Clutch components and operation were carefully studied in detail as clutches on this model were notoriously bad. The clutch assembly was then shimmed and aftermarket Barnett clutch plates fitted.

The frame had a footrest mount and plate torn off so this was turned, threaded and finished by hand to match an original. Once it was welded, ground and painted the result was pleasing. I machined new swingarm bushes and also machined tapered rubber bushes for the rear suspension – not an easy job. I cleaned and repaired all tinware as necessary using elbow grease, electrolytic cleaning (good for insides of steel tanks), garnet or glass-bead blasting. Then I was able to move on to dent removal or other repairs. I sprayed the frame black and the coloured paintwork was professionally done from supplied photos and a small sample of original paintwork.

DEVIL IN THE DETAIL

Chromed components, especially corroded parts, are a real nightmare. I removed some chrome myself (it’s easily done electrolytically) but the underlying nickel and copper layer is more difficult. Apparently some Japanese bikes of this era have different compounds of nickel, which can be relatively thick by today’s standards and consequently difficult to remove. I gave this work to Vince at A A Vinney’s in Dandenong, Victoria, who did a very good job. He also did bright-zinc plating of various parts like fasteners and springs.

I used some stainless steel fasteners where appropriate but always ground and polished them before fitting. All alloy parts were cleaned of major defects then laboriously sanded and finally polished.

The original rims were chromed then wheels were rebuilt using NOS spokes. Scott at Pablo’s Motorcycle Tyres recommended and fitted Pirelli tyres that look fairly authentic, but more importantly they feel secure on the road as well as during laps of the Broadford Circuit last Easter.

All electrics were checked for correct resistance – not having a megger tester, I used a 240V series lamp to test insulation. I made a shadow clipboard and copied the original wiring harness using new cable, terminals, plastic sleeving and self-amalgamating tape to replicate the original.

After I obtained special dampening fluid the speedo and tachometer were overhauled. New mileage decals were fitted. Then I calibrated them on my lathe after doing the calculations and making a holding jig.

I fabricated some control cables and sourced others as NOS. The YDS had three different-style handlebars so inevitably some cables were incorrect length – I modified them to suit my flat ‘bars. I reckon some cables were made six times before I was satisfied that the carbies and oil pump worked in unison and the cable run was neat.

The carbies were much corroded so I boiled them in acid, soaked them in solvents and then cleaned them ultrasonically. Brass emulsion tubes, jets and screws were carefully removed and cleaned using an ammonia-based solution in an old rotating jewellers cleaning machine. It took hours before all the small holes were clear of corrosion. I shimmed then bench tested the oil pump as the pump’s stroke is critical, particularly at idle speed. Once it was fitted to the engine I primed the pump and ensured oil was getting to each inlet port. I machined a spark-plug adapter for a dial-test indicator and set the ignition timing. The engine was fitted to the frame without barrels and pistons simply because they had not yet been machined. The reduced weight made it simple to fit the engine on my own, unlike the challenge of fitting a heavy Honda CB750 K1 engine 12 years ago.

THE MOMENT OF TRUTH

With a small temporary petrol tank fitted, allowing better access to the carbs, it was time to fuel it up and give it a second life. After several minutes of kicking it finally fired. Blue smoke wafted up the neighbour’s hill for ages afterwards as the engine cleared itself of the surplus oil that had obviously accumulated in the crankcase during the rebuild. Once the bike was completed I ran additional oil in the fuel for the first 500 miles, slowly reducing it while trying to vary the rev range without labouring or stressing the engine. The contact-breaker points soon closed up due to initial wear of the cam follower, which then affected timing and made the bike sluggish. After resetting the points the timing was checked and found to be exactly on specification. I now began to increase the rev range and the bike started to feel quite strong and ran well.

AT THE END OF THE DAY

Overall the bike feels quite solid. Weighing in at only 142kg and being physically small, it’s fun to ride and it handles surprisingly well. The engine feels quite strong for such a small motorcycle from so long ago. There’s adequate torque on tap as long as you keep the engine humming along. Thankfully the clutch feels very compliant and even under heavy loads it doesn’t falter. The brakes, although hailed as excellent in 1964, are not impressive today but they’re still quite adequate.

Having done 1700 miles on the little Yamaha YDS3 in three months of weekend rides as well as the Honda Broadford Bonanza, I’ve found it to be very reliable and a joy to ride. Mike, whose YDS3 inspired me, now lives in Brisbane. He came to Melbourne and we both enjoyed a classic ride through the Reefton and Black Spurs prior to the Honda Broadford Bonanza. Whether riding the Yamaha YDS3 or just following it, the sound of a YDS3 is still music to my ears.