Triumph Pre-Unit Racer

Pre-unit Triumphs are a bit thin on the ground these days, let alone one that pushes out 90 horsepower and pulls just over 90 mph over the 1/8 mile at the drags.

THIS MODIFIED pre-unit Triumph is the result of 20 years of back-shed tinkering by a man who loves racing and doing things that other people say you can’t do. Donny Coveney is self-taught bike mechanic who fell in love with Triumphs when he was a 15-year-old teenager.

He bought a ’67 T-bird while working at Morgan & Wackers in Brisbane.

“I didn’t actually buy it from them,” said Donny, “but from the guy who did their heads. It had been a delivery bike with a sidecar on it. Since then I’ve had about 85 bikes but I’ve mainly stuck with the early Triumphs.”

Donny started road-racing in the early ’80s with a 650 that would rev to 10 grand and pull about 140 mph. After a few blow-ups he went to a pre-unit 880 that ran Sonny Routt cases and cylinders.

“I built the engine after I saw an article in a magazine about DT Howard in Pennsylvania in the good old US of A, said Donny. “He was known for his nitro-burning Triumphs.”

The head was built by the famous Don West who has done, and still does, some of the heads on the fastest bikes in the world. He set up the two-stage Hillbourn injection on it, among other modifications, and got it ready to race.

“The first time I showed up to race it at the old Amaroo track in Sydney, I was told the injection wasn’t legal for the era (Classic Race Pre-’63) of the bike. Luckily, I had anticipated this problem and had all the right paperwork from Hilborn and Routt to prove the injection system had been around since 1945. They let me run and I stared at the back of a pack of 40 bikes because I didn’t have a grid position, but then I overtook 36 of them on the first lap but only run fourth.”

Donny said he ran the engine like that until he had a set of titanium rods made and then fitted them to a Norish crank after he had cut 2.3 kg off with a drop-saw and balanced it to 68 percent. This engine was to see out his road-racing career that finished up when the first of his four sons came along.

“Drag racing now seemed the way to go so that was the direction I headed in.”

What he needed was a purpose-built frame and at the time he was working for Darryl Mclean at RT Racing building top fuel Harley frames.

“It was decided to base the frame on a Norton Featherbed/Triumph-cross,” said Donny. “A jig was built and the frame made out 1.5-inch tube with a cut-down Datsun tail-shaft as its spine. Total cost was about $30.”

Donny managed to keep the cost of his new drag-bike under control by using a $50 Jap 250 front-end from a swap-meet and a pair of RG 250 wheels; the fuel tank cost $2; and the guards, which is a FLH front guard reversed on the rear and a Softy front on the front, were virtually a gift from Bomba at King Pin Choppers.

With Routt cases becoming thin on the ground (only three know sets in Oz) and several other Triumph projects on the back burner, Donny realised it was time to start producing his own parts so he got together with his machinist mate Ghillie.

“We put our heads together and started to produce the billet crankcases that are fitted to this bike.”

Using all the above mentioned engine mods, Donny now added Ross forged pistons, stainless steel hard-chromed valves, elephant foot tappet adjusters, lightened rockers, and a set of cams designed by Ray Hudson and Donny and built at Ray’s business, Crow Cams.

The ignition system is a total lost system via an ignition amplifier that fires twin plugs via Dyna twin outlet coils.

The exhaust was built by Pommy Pete.

The gearbox is five-speed Triumph and is connected to the engine via 900 Sporty belt-drive that Donny modified himself because he needed something better to handle the power.

“The clutch runs Barnett plates which were given to me by my good mate, Mal Crompton,” said Donny. “They originally came out of Mac The Brush’s award winning Sporty that Mal had bought years ago to race.

There are a lot of other handmade parts, like the forward controls, but there are far too many to mention because it is virtually the whole bike. What Donny does want to say is that now all the bugs are ironed out of the cases, he has a few sets to sell. If you’re interested give Donny ring on 0400-017-138 have chat to see if these will fit the bill.

“I now want to move on to my next projects which are billet three-valve heads and getting John Clife’s world-record-braking drag-bike which is in the corner of my shed back on the track. It ran an 8.37 at 170 mph on nitro at Santa Pod raceway in 1975.”

Donny finally said that he thinks he has mentioned most people who have been involved with his bikes and the development of his engines over the year but if he has missed some, thanks a lot, but special thanks go to Mal and Ghillie.

words & pics by Keith Cole

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