May 1963, Cycle World's glowing review of the new Johnson Motors T120C TT Special. The road test would have been conducted during March 1963 at the very latest in order for the magazine to go to press towards the end of April 1963. The images show a man tilling fields and are largely taken in fields prepared ready for sowing, which takes place in California principally between March and May. [Correction received from Eric, August 2017, the owner of a '67 JoMo TT (another from the December 1966 batch of JoMo ones with the '65 frame)]:

"The machine (a grader with scraper / teeth) is prepping a race track , see the grand stands in the background. Likely the drag strip was on the same property as the dirt oval being prepped. Giving the photographer a nice backdrop for pics." Sounds right to me - I was clearly mistaken!]

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It's likely therefore that the test was conducted in March 1963, using either one of the first batch of TT Specials (built December 1962) or the second batch (end January - early February 1963). There is no mention of 12:1 pistons in the factory records for the second batch, though the first batch ones have the following entry in the engine assembly record: "ET ignition E3613 pistons (eg 12/1 comp ratio) USA". 

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[The road test could conceivably have been completed in early April 1963 in time to go to press at the last minute, but in all probability it was March or earlier. We can only guess whether the lack of an entry for high comp pistons was just an omission, or whether the second batch of TTs had standard 8.5:1 pistons.]

 

The 2nd batch of TT Specials was shipped to JoMo between 13 - 21 February 1963 and would not have arrived until sometime in April 1963, after the road test would have been conducted. The bike in the test does not have the appearance of being fresh out of the crate (different exhaust system fitted, for example) and would (one would hope!) have some miles on it, given the "unmerciful flogging" meted out to it by the Cycle World hacks. It seems likely therefore that it was one of the first batch of 66 TT Specials built between 6 - 10 December 1962. 

 

JoMo had been requesting stripped-down 650 twins from Triumph for several years, and eventually received them (the TT and single-carb Trophy Specials) with the introduction of the unit-constuction 650s in February 1963 (the first batch left the factory bound for California 12 - 19 December 1962 - before the "Big Freeze", which would have no doubt delayed shipments). The bike used in the test would have been in use for around 6 weeks in all probability, had some low mileage on it but run been in. To achieve 123.5 mph from what was in essence a stock Bonneville with high compression pistons, bigger carbs and megaphone silencers was more than simply an achievement - it was a bloody miracle! Anyone who knows anything about 650 Bonneville's will tell you the maximum top speed on one would be 110 mph - on a good day. Yes, I know they were named the "T120" because they were supposed to do 120 mph - and the T140 was supposed to do 140 mph - but in reality the only way a standard one would make these kind of speeds would be with a tuned speedo! I don't believe it.

 

I have received what I believe to be reliable information that this TT was specially prepared by the JoMo service department (as were many, to customer order), and these were the specs:

 

• Ported head 

• Oversize intake valves

• Jomo 15 Cams with R tappets

• Jomo springs, collers and keepers

• Jomo pushrods

• Bendix points plate

• Reoriented pressure relief

• T120R pipes with T100R megaphones

 

With these enhancements, I believe the test bike could have achieved the claimed speeds. I can't be certain of the truth behined this story, but I have received it from a reliable source who claims to have been given the information by two JoMo personnel who were there at the time. Maybe true, maybe not - but it sounds plausible.

 

At the time of the test the TT Special was a purely "West Coast T120C" - though TriCor had already placed an order for an initial sample of 11 which left the factory in early April 1963 (ironically from 1964 onwards, TriCor - by far the bigger distibutor in terms of sales volumes - received more "West Coast T120Cs" every year than JoMo)  As Cycle World mention, TT racing took place "all over the country" so it's not surprising that the East Coast too wanted a piece of the action when a purpose-built TT racing machine was announced.