OLD 2-stroke bikers like me have our own Axis of Evil. We glare when we hear "United States Environmental Protection Agency", "EU Emission Regulations" and "Kyoto Protocol". Regulations flowing from this wicked trio have killed the manufacture of most 2-stroke road and trail bikes. Search if you will, you won't find a 2-stroke commuter motorcycle, mid-ranger, dual-purpose machine, performance road model or road racer.
This is sad and wrong-headed. Compared to the same-sized 4-stroke, a 2-stroke motor is more powerful, has vastly fewer components and consumes fewer of the world's precious resources. Two-strokes can also be designed to run cleanly and fuel-efficiently, if there is a will to do so.
True, in recent years Yamaha has led a 2-stroke renaissance in motocross. But it takes more than a YZ125cc and a YZ250cc to make a summer: aside from these bikes and a few boutique KTM, Husqvarna and TM models, the curtain has fallen.
Actually, those nasty regulators can't take all the credit/infamy. Had trend-setting Honda, Suzuki, Yamaha and Kawasaki designers pressed on with research and development to devise cleaner 2-stroke engines (perhaps fuel-injected ones) we enthusiasts would be smiling.
Yamaha's wily manufacturing strategy should be acknowledged, although it's confined to the motocross track, where emission regulations are somewhat less stringent.
Yamaha once led the move to 4-stroke motocross technology. About a decade ago, it took advantage of AMA race rules which decreed 4-strokes of up to 450cc could compete against 250cc 2-strokes; 4-strokes of up to 250cc could compete with 125cc 2-strokes, and so on.
The Triple Tuning Forks company released the first competitive 400cc and 250cc 4-stroke motocross bikes for many a long year. They were heavier, less reliable and more expensive to buy and maintain, but 4-stokes could once again win motocross races, and on a scale not seen for more than 40 years.
Four-stroke motocrossers became flavour of the month and soon the big manufacturers were all making them. In the past decade the technology has vastly improved, with the bikes now lighter and more reliable. For a while it was a fashion statement to trade in your old 2-stroke motocrosser for a new 4-stroke.
Cunning Yamaha has continued manufacture of both 4- and 2-stroke motocrossers, preserving customer choice. Other big manufacturers have consigned their 2-stroke motocross designs to the bin, but Yamaha has kept re-badging its YZ 250cc every year since 2006.
Even this rather niggardly effort at championing the 2-stroke cause has paid off handsomely for Yamaha. Youngsters are rediscovering the advantages of riding 2-strokes - a huge power-hit, plus relatively low costs when things go wrong with the motor.
Yamaha's 2-stroke sales are booming.
Online motocross forums are full of pro 2-stroke comments, with many riders saying that while 2-strokes remain eminently competitive, they're also lighter and much cheaper to maintain and rebuild.
There's an unexpected environmental backlash against 4-stroke motocrossers. The 2-stroke's scream does not carry as far or annoy half as much as the thunderous roar of a pack of 4-strokes, so noise levels from motocross tracks worldwide have increased, with some forced to close.
Compared to the same-sized 4-stroke, a 2-stroke motor is more powerful, has vastly fewer components and consumes fewer of the world's precious resources.
Two-strokes can also be designed to run cleanly and fuel-efficiently, if there is a will to do so.thunderous roar of a pack of 4-strokes, so noise levels from motocross tracks worldwide have increased, with some forced to close.
In New Zealand, the icing on the cake has been that motocross icon Darryll King has taken out the national MX2 250cc title (250cc 2- or 4-stroke division) for the past two years on a YZ 250. King could probably win riding any competitive machine, but the fact is that he's winning on a 2-stroke and I can't resist gloating.
New Zealand is also one of a few countries still running a sole championship class for 2-stroke 125cc machines. This doubles as the under-21 championship for up-and-coming racers, having been won by established riders, including Damien King, youngest of the King brothers.
It's interesting to note that in 1996 Shayne King (the middle brother) rode a KTM 360, the last 2-stroke to win the World Motocross Open Title.
So 2-strokes are hot on the motocross track once again. And for caving in to the regulators - instead of going back to their drawing boards - Honda, Suzuki and Kawasaki will just have to watch the 2-stroke party from the sidelines.By Paul Charman