TRI, TRI, TRI AGAIN
If at first you don’t succeed… wait forty years and then enlist the aid of an expert. After an initial series of upgrades in the 1970s weren’t entirely successful, the owner of this 750 Triumph triple tried again. Rowena Hoseason reports
This bike attracts attention. Since its most recent rebuild was completed last year, owner Greg has ridden around a thousand miles while the much-modded motorcycle settles down in its current incarnation. The T150 turns heads everywhere Greg takes it. ‘I’ve had comments that the Trident looks great – and of course I agree,’ comments the proud owner. Sometimes that attention can feel a little uncomfortable, mind. ‘It was even ogled by a highway patrol officer who drove beside me for a kilometre or two!’ Greg escaped the scrutiny of the law without being booked or even pulled over – but his fivespeed Trident most definitely draws a crowd.
The triple was an unusual machine in New South Wales, even when Greg bought it new back in the mid-1970s. ‘I realised from the beginning that the right-side gear shift was becoming a thing of the past but I wanted a traditional English motorcycle, so pretty much had to have a Trident. Another contender at the time was a Norton 850 Commando Interstate, but by 1976 they were the Mk3 models with a left-foot gear shift.’
Greg’s T150 was built in October 1974 and features the petrol tank and paint scheme of the 1974 UK machines, although technically it’s a 1975 model. Some of its cycle parts are common with its electric start successor: ‘ The kick-starter is a T160’s and the clutch outer is partially machined for the T160’s electric start ring gear, but this was never fitted.’
Back then, the Australian licencing regulations allowed learners to ride any capacity machine without a pillion – so the British superbike was Greg’s first motorcycle! ‘ There were definitely lessons learned… to the detriment of the Trident, including a number of crashes.’
However, as Greg’s skills developed he soon discovered the benefits of riding a sure-footed Britbike compared to the multicylindered opposition from the Orient. ‘I did enjoy riding the motorcycle. Friends with whom I rode commented that the lines the Trident took through corners were more gradual than the Japanese motorcycles of the day, and they weren’t able to follow them. The Trident was able to be hustled through the corners quickly.’
There were other benefits to sticking with an air-cooled pushrod engine. ‘Whilst it wasn’t totally reliable, I was always able to get home after roadside repairs and fiddling. The relatively simple nature of the mechanical components and electrics helped.’ The Triumph’s straightforward engine design also encouraged a spot of homegrown tuning, with rather mixed results. ‘High compression pistons of standard capacity were fitted but these stretched the barrel base studs, and high octane fuel was hard to find.
‘ Then in 1978 I had the motor and gearbox blueprinted with the capacity increased to 830cc using 650 Bonneville pistons and the barrels sleeved. At the time the motor had done about 12,000 miles and the main bearings were found to be down to the copper! There was little metal left at the base of the barrels, where it developed an oil leak.’ That issue should have required some attention – but fate had other plans…
‘ That September I high-sided the motorcycle. The left-side footrest arm rotated downward while I was leaning well over into a left-hand corner and this lifted the rear wheel from the road. The resulting crash left the motorcycle economically unrepairable. It had only covered 13,126 miles.’
That’s what happens to so many motorcycles: thrashed, crashed and (in this case) stashed…
During the 1980s, the Trident’s engine was borrowed by a friend of a friend to be used for a while in a speedway sidecar outfit. Over the years the bike was stored with varying degrees of weather protection and good intentions to have it restored. Three decades later work would finally begin in 2010, when Greg set about locating the components he would need and someone suitable to do the spannering. With triples, he says, ‘the work must be done by someone who has a proven track record with Trident and Rocket 3 engine rebuilds.’
That someone turned out to be Roy Kilgour, who we see riding the machine in the photos. Roy was working full time so the Trident project took shape on weekends – but that’s OK because, over the four years the project took to complete, the brief developed as Greg came up with new ideas and discovered different components. Roy was up for the challenge: ‘Greg wanted this to be his dream bike with a big bore kit, twin front discs with AP racing calipers and alloy wheel rims. As the build went on, he came up with new ideas and new bits that he had bought, and we worked together to change and improve things as we went along.’
You’ll find a list of the key components in the tech spec, but the heart of the machine is an all-new, Triples Rule 855cc big bore kit, which has proved to be much more successful than the 1970s attempt. ‘It looks original and the bike performs much better,’ says Greg. As it should: there’s a lot of thought and no small level of engineering skill gone into developing a successful method of increasing the Trident’s capacity while side-stepping the problems which Greg encountered back in the day.
The original 753cc (67mm x 70mm) engine used a die cast aluminium cylinder block which had relatively thin walls between the bores. Even at the standard size, the bores would tend to distort when running hot for long periods which is why Tridents have such an appetite for oil. The old-fashioned way of big-boring the standard cylinder block to house bigger sleeves and pistons just exacerbated this situation and frequently led to fractures around the base flange (which might’ve been why Greg’s T150 was leaking lube before its crash in 1978).
These days, there’s enough cash in the economy to pay for a different approach.
Triples Rule sand-cast their big bore cylinder block with thicker walls around each bore to resist distortion and ensure clearances are kept stable. They use A356 aluminium which provides greater tensile strength, and have gone to some trouble to make sure that the cylinder head is robustly secured with beefed-up screw threads for the pillar bolts.
On the road, the company reckon this translates to an engine which will ‘pull authoritatively from lower rpms, handle twoup riding without straining and have long legs: accelerating smoothly from low speeds to cruising speeds without a lot of banging on the gearchange lever.’
This is probably more important to an owner of a T150V than someone who rides an original four-speed triple. Tested in 1975, the five-speeder noticeably ran out of puff at the ton or around 7000rpm, and laboured its way up to 118mph. By contrast ‘the older machines hit 9000rpm like lightning and were eager for more.’
These days, top end speed is almost academic for road riders – but easily accessible mid-range grunt is worth paying for. How much? You may ask. Triples Rule charge $2349 plus shipping for the basic big bore block kit; and the winner of the 2011 Manx GP Formula Classic plainly thought it was worth every penny…
Greg’s motor’s new-century specification also incorporates forged, CNC-machined pistons; alloy, matched weight conrods from R&R Racing, and a high capacity oil pump from Les Whiston of Rob North Triples. It retains the T150’s standard cams ‘but correctly set rather than retarded as it was originally supplied for US emission purposes.’
Greg opted for an hydraulic clutch conversion from LP Williams, carefully integrated by Roy into the ancillaries to look like it had always been there. ‘I went to a lot of trouble to construct a mirror image Lockheed master cylinder,’ explains Roy, ‘so that the front brake and clutch master cylinders appeared as a pair.’ Likewise, the braided clutch pipe looked slightly out of place so ‘we changed the clutch hydraulic hose from the supplied bare metal to black to look more like the standard cable.’
Up front, the suspension has been upgraded with Progressive fork springs, but improving the ride at the rear end was a little more tricky. Greg and Roy went for Hagon’s 2810 (28mm, 10 damping options) gas adjustable shocks, which are 20mm longer than the standard Trident items. ‘As supplied, these should be mounted upside down,’ says Greg. ‘ This was ignored because if installed as directed, with the Hagon branding oriented correctly, the rear brake rod passes through the spring coil.’ A swap to Öhlins rear shocks and fork internals is on the list of ‘future plans’, in any case.