K&DMCC trip to Triumph
The accompanying photograph is of a motorcycle outing from my once-local town, to the Triumph Works, Priory Street, Coventry. In the photo, members of the Kettering & District Motor Cycle Club have gathered outside Bosworth’s Motor Cycle Shop for the 30 mile ride to visit the Triumph factory. Also attached is an artist’s publicity impression of the Priory Street site from about the same period.
Of the motorcycle shop owning family, grandfather Bosworth invented the pneumatic tyre, only for only Dunlop to patent. It went to the high court in London and grandfather Bosworth lost, of course. Later Mr Dunlop acknowledged the invention and offered a royalty, but was refused.
Jeff Waller, email, Spain.
By 1907, Triumph had outgrown their Much Park Street, Coventry factory and with no room for sizeable expansion available, they moved works, to Priory Street, Coventry. After some alterations, the new site suited and later allowed room for further expansion for their booming motorcycle trade, leading them to extend outwards and upwards.
The Much Park Street factory was retained by Triumph for cycle manufacture.
While their volume of production seems minuscule compared to that of today’s large motorcycle makers, when Triumph built 3000 machines in 1909 these were huge numbers, and to supply over 30,000 550cc Model Hs to the British and Allied forces during the First World War was the most by any maker worldwide. Only Douglas of Bristol was, volume wise, in the same league, supplying approximately 20,000 2¾hp twins and over 5000 4hp models, mostly outfits, during the conflict.
On the night of November 14/15, 1940, an enemy bombing raid, comprising over 400 aircraft, destroyed much of Coventry’s city centre with loss of life and many seriously injured. The city’s cathedral was gutted and a few hundred yards away, so, also, was Triumph’s Priory Street works, while a new pre-production batch of 50 3TWs for the military were lost as well.
Triumph temporarily relocated to Warwick, housed in buildings which looked more like a village hall than motorcycle factory – but with equipment salvaged from Priory Street, in true spirit they made do and got on with the jobs in hand. With Government help, work started on Triumph’s new works at Meriden in Summer 1941 and by March 1942 the first equipment was installed.
When trying to adjust the valve clearances for my 1964 Triumph 5T, how can I get two spanners and a feeler gauge strip into the small opening once the inspection cap is removed? Can you also confirm clearances, please, as different figures are given for the 350 and 500cc unit models.
Dan Hanson, email.
Different people have differing approaches. I remove sparking plugs, select top gear and turn the engine over using the motorcycle’s rear wheel, with the sparking plugs removed. Some prefer to ignore the above and use the kick-starter with plugs out. All Triumph’s twins have their valve clearances set when the engine is cold.
Taking an example inlet valve, or exhaust valve, turn the engine until the subject valve’s rocker moves down to open the valve, continue until it again rises and again continue until it has totally released the valve, the rocker is stationary and its mating inlet or exhaust valve is opening/open. This valve clearance can then be adjusted.
Figures and method: 3TA and 5TA (349 and 490cc unit twin)
Inlet valves (back of engine): 0.010 (10 thou) or 0.25mm.
Loosen lock nut using Triumph key (or appropriate thin spanner) while holding tappet adjuster square end with another key/ spanner. If using a spanner here it needs to be a tight fit as it’s easy to round the adjuster screw flats – which is very annoying to deal with! Adjust until there is no clearance
(no play in either plane but not starting to compress valve spring). Back off adjuster by ¼ (90 degrees) of a turn. Due to thread pitch, this equates to 0.010inch clearance. Secure adjuster with key/spanner and tighten lock nut.
Turn engine with rear wheel until the newly adjusted inlet valve is compressing its valve spring. At this point, the other cylinder’s inlet valve will be fully shut and its rocker stationary. Adjust valve clearance as above.
3TA and 5TA
Exhaust valves (front of engine): 0.010in or 0.25mm
Proceed as per inlet valves.
The sporting Tiger 90 and Tiger 100/ T100SS have tighter valve clearances, but basic procedure is as above.
Tiger 90 and Tiger 100SS (349 and 490cc unit twin)
Inlet valve clearance: 0.002in (0.05mm) Adjust until slight up and down movement of rocker is felt, or lift rocker fully and then tap with finger to give a just audible click. Lock off.
Exhaust valve clearance: 0.004in or 0.10mm.
Adjust until there is no clearance but absolutely no compression of valve spring is occurring. Turn back adjust by ⅛turn which will give desired 0.004 inch clearance. Lock off.
The above is culled from Triumph factory workshop manuals. Some will still wish to check their work with feeler gauge strips, which can, by bending strips, be done, but, from my experience, the factory developed method works well.
Inspection cap washers are often reusable, but always check for damage or seating before refitting and replace if appropriate.