Filling up the quad with increasingly costly unleaded petrol is frustrating, especially when there’s a tank full of red diesel costing one-third the price in the yard. Is diesel power a realistic option?

Lack of refinement, excessive weight and sluggish performance are among the factors that have deterred many ATV makers from considering adding diesel options to their unleaded ATV line-ups.

And given that ATV developments are driven by the American market where petrol is still relatively cheap compared to UK prices, the logic is clear to see.

But against that trend, two manufacturers are extolling the virtues of oil-burning quads, namely Anglesey-based Diesel Quads with its Diablo 850 and Roush Special Vehicles with its diesel-power conversion of an Arctic Cat.

The Roush machine is expected to enter full commercial production early next year, running off Arctic Cat’s production line in the USA and being sold through Arctic Cat’s existing dealer network.

It’s expected that the Massey Ferguson’s dealer network will distribute the bikes in the UK.

In contrast, the Diablo has been rolling out of Diesel Quads’ workshop since the beginning of this year.

The 6495 Diablo is said to be up to 80% cheaper to run than competitors’ petrol-engined models thanks to its use of a 21.5hp Yanmar three-cylinder water-cooled diesel engine that can be fuelled on red diesel.

Torque produced by the three-cylinder diesel is said to be close to 50Nm, enough to handle the ATV’s one-tonne towing capacity, plus 50kg front rack capacity and 60kg rear rack load, according to the Welsh manufacturer.

The use of shaft drives puts traction to all four wheels, with two-wheel drive being selectable.

The Diablo’s variable transmission offers high and low ranges and the ability to run at up to 60kph.

Bringing it all to a halt are hydraulically operated disc brakes.

Diesel Quads’ Diablo

• Engine: 21.5hp Yanmar 3-cyl, 854cc
  
• Transmission: Belt driven variator 0-60kph
  
• Front rack capacity: 50kg
  
• Rear rack capacity: 60kg
  
• Towing capacity: 1000kg
  
• Brakes: Hydraulic disc brakes
  
• price: £ 6495

“You know it’s a diesel-engined ATV, but it is smoother and more refined than any previous model produced,” says the maker’s Gifford Langley.

“And with water-cooling, the engine is as quiet as a petrol version.

“We’ve sold about 17 so far this year and the feedback we’ve had is encouraging,” says Mr Langley.

“The only drawback is that at 380kg, the ATV is a bit heavy, which can take some man-handling if you ever get stuck.

“But the weight does help with traction and with fuel use of about 1-litre/hour, running costs are low.”

Roush’s diesel quad has one less cylinder, using a Lombardini two-cylinder diesel rated at 18hp and delivering 39Nm of torque.

Based on an Arctic Cat chassis that offers 330mm of ground clearance it boasts an adjustable suspension system, enabling the rider to select optimum comfort settings to suit the conditions or load.

The water-cooled diesel engine is naturally aspirated and puts its power to the wheels through an automatic gearbox, with high and low ranges. Roush says it is an installation that provides responsive acceleration and engine braking.

The diesel quad can handle towed gross trailer loads of up to 500kg, with load carrying capacity extending to 45kg on the front rack and 90kg on the rear rack.

Roush Diesel ATV

• Engine: 18hp Lombardini 2-cyl, 686 cc
  
• Transmission: Automatic with high and low ranges
  
• Front rack capacity: 45kg
  
• Rear rack capacity: 90kg  
  
• Towing capacity: 500kg
  
• Brakes: Hydraulic disc brakes
  
• Price: £ 7500. Apporximate forecast price for launch early 2006

diesel development

Martyn Heard, from UK Bombardier importer Jets Marivent believes that despite getting many requests from customers, Bombardier will probably not introduce a diesel option.

“The total US market is estimated at over 1m ATV’s each year, which compared to the UK’s 20,000-or so for leisure and utility use, negates the development of diesel power,” he says.

Given the firm’s progress in petrol engine technology, there’s greater efficiency still to come from using unleaded petrol, according to Mr Heard.

“With an 800cc direct injection petrol engine, our latest Outlander is proving to be more efficient than our 500cc machine using carburettors,” he says.

“And we’ve also carried out several LPG conversions with success too.”

fwmachinery@rbi.co.uk