Bultaco 360 Frontera
BULTACO 360 FRONTERA
Cycle World Road Test
The Pursang Gets Lights And A Lust For Medals Made Of Gold.
■ BULTACO HAS, like most manufacturers, made two different motorcycles for motocross and enduros. Pursangs for MX and Matadors for enduros. It seemed the logical thing to do. In those days, everyone was clamoring for high-horsepower racers that did not lend themselves at all to plugging along through a thicket of trees or muddy streams. For enduros, the Matadors had many of the better features of the best off-roaders and they handled better than just about any other enduro machine.
Recently, Bultaco has reversed its high-horsepower philosophy regarding MXers and has produced what amounts to the torquiest Pursangs ever. Particularly the 360. The bikes are no longer horsepower kings, but the tractable grunt they produce makes them slingshots out of corners and very acceptable play bikes.
The Matadors have remained sluggish because of their weight. And high-speed handling suffers, as well. But Pursangs have no lights and therefore are not enduro legal. Also, their close-ratio transmissions would not work well in the wide-open spaces. So Bultaco took on the task of incorporating the best features of the Matador with the strongest features of the Pursang. At first glance, it appears as though all they’ve done is installed lights on the MXer, but lights are not the only thing that make the Pursang and the new 350 Frontera different.
The new bike sports a set of wider ratios in the transmission, as well as some additional silencing that includes a built-in spark arrester. Other changes include a larger fuel tank, different type carburetor and a speedometer. The pointless Motoplat ignition has been replaced with a conventional magneto/coil system because it is easier to operate a lighting system off the latter. But the important parts of the motorcycle, the frame, suspension components and the engine’s power, remain unchanged from the Pursang. The Matador still lives; but for something that gets on with the gettin’ on, the Frontera does it best.
The Frontera is one of the few machines that can get away with having its engine unchanged. The stock motor pulls strongly from the word go. Port area is abundant, but not radically timed. Compression ratio is 10.5:1 (uncorrected), which allows the mill to deliver good power without the high heat buildup caused by smaller squish volumes.
If there was a shortcoming in the old Pursang engine, it had to be carburetion. Once running, the Amal carb would work well, but getting the engine to fire was a chore at times. To alleviate the possibility of the occasional difficult start—since the machine was designed for two-day trials where points are deducted for failure to start within a given time period—a new Amal carburetor has been put to use on the Frontera. The carb has some very M.ikuni-like features and characteristics. There is an enrichening lever to eliminate the need to tickle the carb until gas flows all over your hand. With the enrichener deployed, the engine springs to life after just a few prods on the kickstarter. And you can ride off immediately, with the choke depressed if necessary, to avoid penalty points in a qualifier. Carburetion on our test bike proved to us that the switch to the new Amal was worth it. Only once was the machine hard to start, and then all it took was a few extra kicks.
Operation of and gear spacing in the transmission were ideal. The left side shifter, which snakes from the shift shaft under the lower edge of the drive chain and then out along the side case, was well positioned. It was out of the way when you didn't need it but always just a flick of the toe away when you did.
Handlebars, seating comfort and position, and the great footpegs are the same as on all Pursangs. The machine does sit tall, but the feeling disappears once underway. Long rides are no problem. Everything fits comfortably. Even the new fuel tank.
Decked out in red with yellow striping, the tank, carrying 3.0 gal. of pre-mix, is the highlight area of the bike’s styling scheme. The depository has a new shape that gives it increased volume. The rear of the tank is slim, considering how much fuel can be carried, since most of the petrol is located in the forward portion where the bulbous shape does not interfere with rider mobility. Behind the tank cap there is a small pouch that can be filled with spare tools. It is very sleek and far from the groin-endangering leather lunchbox found on our MZ 250 test bike (CW April ‘75). If a rider feels that he needs to carry more than will fit into the pouch, there are sufficient places on the machine to which he can strap spare shifters, vice grips, etc., although they would probably never be necessary.
The majority of good enduro bikes have up-pipes. It is this fact that made us leery of the Frontera’s low-slung chamber, even though it had a small bash plate attached to the frame as protection. But the pipe's undersides came through the test unscathed. Muffling at the tip is via a reverse-flow silencer. It is very quiet for a big-bore two-stroke. The exhaust system incorporates a Spanish-built spark arrester, but the unit is not stamped approved by the U.S. Forestry Department.
The Frontera’s hubs are made from Dural, a lightweight alloy. Rims are ridgeless Akronts with Pirelli tires mounted. Both front and rear units are very light and the brakes work fantastically well w'hen dry. The rear brake never needed adjustment during our test, but the front brake needed quite a bit of attention. The progressive power of the binders was a tremendous aid on some of the steeper downhills where traction was sometimes questionable.
We had the opportunity to test the Frontera in its natural element, the two-day trial. While this type of event would subject it to an even more grueling test than we would normally be able to give such a machine, it did point out a few areas where the Bui could use a bit more work.
The bike was ridden by a CYCLE WORLD staffer in the California City ISDT Qualifier. While all of the Fronteras entered in the event were relatively new, our test machine finished well enough to earn a silver medal.
Right off the bat, it wouldn’t start. But stubborn as we are, we just kept kicking away and after a few more tromps it lit. We warmed it up for a few seconds and then rode out of the starting area. Two miles down the road, with the engine still not up to full operating temperature, it seized mildly. Fronteras come from the factory with very tight piston clearances. An owner would do well to ride easily for 100-200 miles, then take the top end off his bike and check it before he goes racing for the first time. The seizure never really got a chance to grab tightly because the clutch was immediately whipped in, and after coasting 50 yards or so, the engine bump started without complaint. After that point, anytime the going got so rough that it would put a heavy strain on the engine, the rider simply reached down and closed the choke. This is one feature of the new Amal of which we really approve. On a Mikuni carburetor, using the choke lever on a warm engine would cause it to either die or sputter so badly as to make the machine nearly unridable. The choke lever on the Amal allows the engine to run almost as though it weren’t on, yet the richer mixture helps prevent overheating and resulting seizures.
On the first day of the qualifier, the bike handled very well. It had a tendency to shake its head at high speed through sand, but the front end is very light and with power on would skim the ground for hundreds of yards at a time. This alleviated the insecurity of direction. The suspension behaved perfectly. The long-travel (8.25-in.) front forks delivered an extremely controlled ride, as did the forward-mounted Telesco shocks, which, in their current position, yield better than six inches of travel at the rear axle.
Day two had the on-time Bultaco starting right away and smoking off into the early morning desert. But as the second day wore on, the suspension components began to lose their damping. The rear shocks and front forks still had the original factory oil in them. Those riders who had changed to Bel-Ray oil before the weekend event found much less damping fade taking place. Fresh oil in the forks and the shocks, which are rebuildable, returned everything back to normal except for the fork springs. The standard Bultaco springs sack out sooner than one might hope, necessitating replacement. Bultaco rep Mike Hannon recommends using S&W springs, which are sold and distributed by Webco.
The only other problems we noticed on Fronteras during the two-day (apart from an occasional mechanical problem), were on machines other than the one ridden by the staff. The standard fiberglass fenders crack easily, even without crashing. The vibration gets to them at the flex points and eats away. The front rim on one bike had a minor ding on it. Those Frontera riders who did not use a double nut and Loctite on the rear of their exhaust pipes found that they will work loose and the rear cone possibly fall off.
The test that this Frontera underwent, and will continue to undergo as TEAM CYCLE WORLD contests all of the ISDT qualifiers, will be the most rugged any motorcycle has ever endured while in the hands of a magazine staff. It will be thrashed by very fast riders, in the roughest of terrain, and we expect, judging from our first outing, that its DNF record will be nonexistent.
Bultaco’s Frontera is not a perfect machine. Heaven knows we’d all be out of jobs if perfect machines rolled off the ends of assembly lines. But it doesn’t need any major work to do its intended job. All an owner need do is make sure that he maintains the machine to factory specs, keep an eye out for the occasional loose bolt or spoke and replace the fenders with something less brittle. In stock form the Frontera is fast, torquey, it handles, is comfortable, slides like any good Bultaco should, can be thrown around like a 125 because of its weight, suffers less carburetion hassles than ever before, is comfortable and enduro-legal to boot. You can also motocross it successfully if you have a hankerin’ to.
A great philosopher once said, “Fire-breathing motocrosser does not a good enduro bike make.” It is obvious to everyone here that the great philosopher never rode a Frontera. [Ö]
BULTACO 360 FRONTERA
$1595
