Trials Bike Test
Observed trials has had a tumultuous relationship with four-strokes since Sammy Miller’s Bultaco won the 1965 Scottish Six Days Trial, breaking a 30-year stranglehold on the sport by four-strokes.
In the aftermath, Honda was the primary torchbearer for thumping trials bikes, occasionally winning world championships against two-strokes, which remained the standard bearer for the local riders.
The James Dabill-piloted, Honda-powered, high-tech fuel-injected Montesa Cota 4RT brought four-strokes back to the Scottish winner’s circle in 2007 after a drought of more than 30 years.
And while Honda (via Montesa) has dominated modern-era four-stroke observed trials, that hasn’t stopped French Scorpa (Yamaha-powered, now bankrupt), Spanish Sherco and Italian Beta from offering their own thumper alternatives.
However, only the Montesa Cota 4RT has been a consistent winner and seller, with world championships from Spain’s Toni Bou (2007-10) and Japan’s Takahisa “Fujigas” Fujinami (2004).
Betamotor has not been a major player in world observed trials as of late, though Beta has seven world championships to its credit, thanks to Dougie Lampkin (1997-99) and Jordi Tarrés (1987, 1989-91).
Instead, the Italian factory that has been producing wheeled vehicles since 1904 in the Florence area, has focused on clubman-friendly mounts that combine performance with a substantial reputation for reliability and high-quality finish.
The 2010 Beta Evo 250 4T is an outstanding example of the company’s dedication to the local rider who has a handle on his capabilities as a competitor. While the natural inclination of many is to select whatever model the most highly skilled performers win on, in many cases a more docile motorcycle can be a superior choice for a rider with less prodigious talents.
Like any Italian motorcycle, the Beta Evo 250 4T is something of a work of art. The single-spar aluminum frame is unique and sleek, while the Beta-developed SOHC four-valve motor has a purposeful look that blends well with the serpentine exhaust system (a titanium version is available as an option).
The frame doubles as a fuel tank, reducing visual clutter, as well as weight. Many optional bits are available from the Beta factory to improve the Evo both visually and from a performance standpoint.
The 250cc motor has a compression ration of 11.5:1, yet it requires only an extraordinarily light kick to get started. And, although it lacks the electronic trickery of fuel injection, the 33mm Mikuni SE BSR carb seems to work magic on the thumper. There is a switch that gives you a choice of two ignition mappings, but the difference is minimal–we stuck with the “aggressive” setting rather than the “soft” alternative.
While the carburetor has knobs for both choking and hot-start conditions, neither seems to be necessary. Riding in a variety of conditions, the Evo 4T was a one- or two-kick starter requiring either no throttle or just the slightest crack.
Once started, the Beta motor immediately settles into a secure (and virtually silent) idle, even when completely cold and the choke left untouched. Some may have had negative experiences with CV carbs on other motorcycles, but the combination of this Mikuni and the Beta motor is uncanny. Any riders who gravitated to the Montesa Cota 4RT due to its EFI can consider the perfectly carbureted Evo as an alternative.
Beta offers a 300cc version of the Evo, with this 250cc model designed to satisfy the less-than-expert riders. Certainly, the Evo 250 4T is soft off the bottom, as intended. The compression ratio is not excessive, and the short stroke (77mm bore and 53.6mm stroke) design is more rewarding of revs than pure off-idle grunt. Again, this is a good thing for an Intermediate (or below) rider, as smoothness is almost always going to be superior to brute force.
In some ways, the powerplant of the Evo 250 4T reminds one of a 200cc two-stroke trials bike motor. It’s smooth off idle, then delivers decent mid-range before signing off. The 250 revs out nicely, and power is on tap when riding the loop or tackling long hillclimbs.
On hills–both on the loop and in sections–the 250 is happy to pick its way up, or run up the revs and fly. Either way, the four-stroke motor finds traction and delivers the power to the ground. 250 or larger two-strokes on many of the same hills will fishtail and spin the rear wheel. On the 250 4T, the tubeless radial Michelin X11 rear tire never hunts in vain for traction.
The hydraulic clutch pull on the Evo 250 4T is fairly hard for a trials bike, where you are working the clutch almost continuously, even on a four-stroke. There are time-intensive fixes–lots of filing, basically–but it would be nice to have a lighter touch out of the crate.
Beta had gone through a period with non-linkage rear shocks on the the Rev 3 series, but the company has returned to a linkage system on its trials bikes. This adds a bit of unsprung weight, but it is fairly centralized. Also, linkage means more service. However, Beta clearly decided that a variable damping shock is not an adequate replacement for a rising rate mechanical link.
On-ground action of the suspension is good and it tracks through uneven rocks uneventfully. However, the Evo’s rear shockseems to suffer from hydraulic lock upon landing the 159-pound machine (claimed, “in running order [dry]”) when it is launched off of rocks. It definitely can cause unsettling of the chassis when the rear suspension’s intransigence makes itself known.
The 38mm Paioli forks are nice and lively, a plus for trials riding. While the spring rate is soft, the relative lack of rebound damping allows the front end to resist packing on repetative bumps. This also facilitates moving the front end around, either by hopping or executing a floating turn. The absorption rate is smooth, and deflections in turns are minimal.
Beta trials bikes are know for their turning manners and the Evo 250 4T is no exception. The front end is pulled in tightly, so you can carve corners with welcome accuracy. There’s no pushing at all, but you must be aware of a tendency to tuck in turns, especially when dropping off a rock.
The more extreme the bike’s position, the worse it feels. Being aware of the handling quirk is half the battle, so it’s just a matter of being prepared for a tendency to tuck when pulling off that sort of turn. Even though it turns tightly and sharply, the 4T is not twitchy at speed on the loop.
Most American trials riders buy more motor than they need. The 2010 Beta Evo 250 4T is an excellent testament to the hoary cliché: “Less is more.” However, in this case, the cliché becomes sage advice.
Experienced trials riders who can get by with 250cc four-stroke performance will be fully satisfied by the Evo, and riders who are looking at a trials bike for its cross-training capabilities will find this friendly mount to be a highly desirable choice.
2010 Beta Evo 250 4T | Motorcycle Specs
Vehicle weight in running order (dry)…159 pounds
Seat height (no seat)…26.0″
Front tire…Michelin, 2.75 x 21″
Rear tire…Michelin X11 tubeless radial, 4.00 x 18″
Fuel tank…2.6 quarts
Radiator capacity…20.3 ounces
Engine oil…15W50, 0.95 quarts
Front suspension…38mm Paioli forks, with rebound and spring preload adjustment
Rear suspension…Linkage single shock, with rebound and spring preload adjustment
Brakes f&r…Hydraulic discs
Type…single cylinder, 4-stroke, 4 valve head, SOHC
Bore x stroke…77×53.6 mm
Ignition…Digital electronic ignition with magneto flywheel alternator and variable advance
Spark plug…NGK CR7EB
Carburetor…Mikuni SE BSR 33-79
Fuel: Unleaded premium
Warranty: 6 month, limited
Motorcycle Riding Apparel
Helmet: Nau Zona Z400
Jersey…Axo Sport Retro
Gloves…Axo Series 19
Pants…Axo Nickel Retro