Triumph Silver Jubilee Surprise | Vintage Motorcycle Tales

Triumph Silver Jubilee Surprise | Vintage Motorcycle Tales
The Silver Jubilee is a sleek, beautiful machine that is light, quick and nimble.

Triumph Silver Jubilee

Back a couple of years ago, I did an article about a friend’s 1964 Triumph bobber for a magazine in the U.K.

When I brought him a copy of the magazine for his scrapbook, he asked me if I was interested in seeing another old Triumph, right across the street from his place. As we were walking over to see it, he mentioned it was a kind of odd silver color and had a blue seat.

More than a little surprised at that, I said, “Are you sure about that seat color? There’s only one Triumph I know of that came with a blue seat and this can’t be one of those. I remember reading about a bike they called the Silver Jubilee years ago that had a blue seat. But I doubt this bike could be one of those.”

My surprise was complete when his neighbor opened his yard barn and there sat a pristine 1977 Triumph 750 Bonneville Silver Jubilee! The bike was being stored in Wisconsin for the owner who lived in Utah.

A quick phone call got me permission to road test the bike and after spending the day riding the bike, I enquired as to whether the bike was for sale — and to my surprise it was!

The reason I was so surprised to see a Silver Jubilee sitting in a yard barn in Wisconsin is that Triumph built only 1,000 of them for export to the United States, a fact underscored by the graphic on the side cover that says “One of a thousand.”

Another 1,000 were built for domestic sale in the U.K. and 400 were built for export to the Commonwealth nations. Those say “International Edition” on the side cover.

The Silver Jubilee Bonnevilles were built to commemorate the Silver Jubilee of Queen Elizabeth II’s 25 years on the throne.

Mechanically, the Silver Jubilee Bonnevilles were not substantially different than the other Bonnevilles of that year. But in bikes that are collector’s items the moment they roll off the assembly line, it is the details that matter.

The SJ models have a “J” in their frame and engine numbers to signify their authenticity, being designated T140J instead of the standard T140V.

Much more chrome is used on the bike on the timing cover, crankcase side cover and other details. A special medallion is affixed to the top of the tank. Red, white and blue hand-painted pin striping adorns the tank, chain guard and rims.

Special silver and blue paint treatment was the only color option and, of course there was that distinctive blue saddle that has red piping and “Silver Jubilee” imprinted on the aft surface.

The bike has its original equipment twin Amal carburetors, disc brakes front and rear, five speed transmission and no electric starter—a feature referred to by period Triumph sales literature as a “traditional manual starter” as though the kick starter is being thrown in at no extra charge.

Somewhere along the way, Thruxton-style mufflers and Boyer Bransden electronic ignition were added. Both are welcome addition, since the Thruxton mufflers give the 750 mill a muscular bark that is not matched by the OEM mufflers and the Boyer ignition eliminates filing and setting contact breaker points and improves cold starting.

This was proven on the very first attempt to fire the bike up. Its caretaker said it had been many months since it had last been started prior to me looking at it. He could not even attempt to start it due to a knee injury.

He did have the battery on a battery tender, so it was fully charged. We put the battery in, “tickled” the Amals and much to my surprise, it started on the third kick!

Riding the Bonneville around the curvy, hilly country roads, I was amazed at the hard acceleration on tap, particularly in third gear, which is aided by the bike’s 390-pound weight.

Handling is quick and nimble and the Triumph Lockheed disc brakes haul the bike down from highway speed quickly and in a straight line. After spending the day with the bike, I made an offer on it and we closed the deal.

The performance comes from the 750cc parallel OHV twin with full circle crank producing a claimed 49 hp at 6,200 RPM. Engine vibration is minimal at normal operating speeds, but becomes noticeable above 6,000 RPM.

In the time I’ve owned the bike, I bled the rear brake system, which turned out to be much more of a project than it needed to be because the bleeder on the rear caliper is on the bottom of the caliper body, which prevents air from being able to be expelled.

Taking the caliper off to rotate the bleeder to the top position didn’t even help. I wound up having to reverse bleed the system from bottom to top to get things working.

When the left cylinder spark plug started miss firing when the bike was up to temperature and new plugs didn’t help, I replaced both ignition coils; the originals said “Made in West Germany,” which has not existed since 1990. I figure those coils didn’t owe anybody a penny at that age. A few other minor electrical system repairs and de-corrosion steps were taken on the original Lucas electric system and a new battery was installed.

At this point, the bike has under 6,300 original miles on the Smith’s instruments odometer. Both instruments are original and work fine. While the Jubilee is not a daily rider for me, I do get it out for some back road riding occasionally and wherever I stop with it, a conversation starts.

Mostly, among those vintage motorcycle enthusiasts who have seen it, there is a common reaction: surprise.


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