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Where are they now? – Geoff Sim | Columns | Gassit Garage

Geoff Sim thought of himself as a ‘big bike’ racer until he hopped on a 125

He rides every day, walks 5km daily, and ideally would fly every day as well. He’s Geoff Sim, Australian 125cc champion in 1975 and ’76, and a motorcycle dealer in Wollongong for four decades.

Sim, 68, owned Centrestand Motorcycles and now has City Coast Motorcycles, managed by his son Tim. He has a hanger at Lake Keepit Airport in north west NSW, where he glides and flies in his kit-built Lancair 320. He’s logged 6500 hours, including a flight to New Zealand, and it returns a fuel consumption figure many car owners would envy.

Sim grew up in Sydney’s Como West and attended Jannali Boys High. His brother Chris pens articles on motorcycle racing history.

Geoff covered 64,000 miles in two years on a Honda CB72, including Clubman rallies with top open-road riders such as the late Paul Giles (Shawn’s father). He started racing the CB72 after watching a friend compete at Oran Park Raceway. Though not a student, he was a keen member of the University of NSW Motorcycle Club. 

“The CB72 was a great education,” he says. “It didn’t have the power to slide the rear wheel, so you learned to push the front tyre on dirt. Later streetbikes included a Yamaha 350 and Kawasaki H2 750, with engine mods and exhausts made by Gary Treadwell. He’s ridden all over Australia, as well as in Bhutan, Nepal and from Peru to Brazil. 

Sim competed in the 1971 Castrol Six Hour production race with John Francis, finishing fourth in the Unlimited class on a Honda CB750. In 1974 he was second in the 500cc class with Peter Stronach on a Kawasaki.

The move to 125 racing
came by chance.

Former international Kevin Cass had invited Sim into the motorcycle business and had bought a Yamaha TA125, which he offered to Sim.

“I’m a big-bike rider,” Sim blithely told Cass, and suggested he let Dave Burgess ride it. Cass convinced Sim to test the bike and he discovered it was great fun. “But I had to break the news to Burgo.”   

The combination of Cass’s two-stroke knowledge and Sim’s riding came to the fore in 1975, when Geoff won the national 125 championship.

In the summer of 1975-76 he raced in New Zealand. His 125 opposition included a Californian teenager named Randy Mamola. The highlight for Sim was winning at Timaru.

“What a great track for a 125, with spiral corners that opened out or tightened up. Randy’s manager, Jim Doyle, thought they’d clean up in NZ, but that didn’t happen.”

In 1976 Sim retained the Australian title, winning at Symmons Plains, Mt Gambier and Perth’s Wanneroo Park, and famously dead-heating for first with Burgess at Bathurst. Both were riding Cass-prepared machines, with Burgess on a Kawasaki-based rotary-disc-valve single.

“Kevin had my bike on methanol and it was a rocket during practice, clocked at 200km/h,” Sim said.

“To save the engine, I would only do half a dozen hard laps and then a plug chop. The cylinder heads were easy to lift on a TA. The pistons were damp around the edges and dry in the centre – so the mixture looked perfect.

“But practice ends Friday afternoon and the race is Sunday morning. Second time down Conrod Straight, the bike was only running on one cylinder. I’d almost pulled into the pits when it chimed back on two. Eventually, I realised the engine was loading up coming down the hill and it would run on two cylinders if I wound the throttle on slowly out of Forrests Elbow.

“On the last lap, I caught Dave down the straight and we had a braking duel into Murrays Corner, followed by a side-by-side sprint to the line.”

In 1977, Sim rode two championship meetings on Clem Daniel’s 125 and then, save for some production rides with Roy Denison, he stopped racing.

“Clem’s bike was no longer competitive and he didn’t want to do any more work on it. He remained a great friend and when the 500 GP live telecasts started on SBS I would got to Clem’s house, even at 2am, to watch the races with him.”

As mementos, Sim has his restored ex-Ron Toombs Yamaha TD1-C 250 racer, his TA125 and his Kawasaki H2. One thing he doesn’t have is lasting injuries. If he travels to the Australian GP, he flies to the Island, takes the bus to accommodation in Cowes and walks to the circuit each day.

On telling that to former 125 rival Barry Smith, he was met with the surprise response: “You’re an ex-motorcycle racer and you can still walk!?”

By Don Cox