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Retrospective: Yamaha YM2C Big Bear 305 Scrambler: 1967

Yamaha YM2C Big Bear 305 Scrambler

Year/model: 1967 Yamaha YM2C Big Bear 305. Owner: Jeff Williams, Los Osos, California.

Photo Credit: Clement Salvadori

Clement Salvadori
November 9, 2011
Filed under Retro + Vintage Motorcycle Reviews

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In the early ’60s the Big Bear race was a pretty serious event, running across California’s Mojave Desert and up to Big Bear Lake in the San Bernardino Mountains. The idea that this beautiful, highly chromed street-scrambler had any possibility of winning against high-strung Euro-bikes like Maico, DKW, Jawa, etc., was a pipe dream. However, Yamaha decided to appropriate the prestige of the name in 1965, without ever having won the race, by calling its YD 250 street-scrambler a Big Bear.

For the ’67 model year it confused the issue even further by also giving its new YM2 305 street-scrambler the same name. This turned out to be a one-year-only model, sold only in the United States, some 6,000 units passing through the dealers.

The parallel-twin, port-timed two-stroke came with a compression ratio of 7.2 to 1, and the factory was claiming an output of over 30 horsepower at 7,000 rpm. The cylinders were bored to 60mm, stroked to 54mm, and fed by a pair of 24mm Mikunis. In turn, these were sucking in a mixture arranged by Yamaha’s Autolube oil injection system, with the oil being introduced into the intake ports, rather than injected into the crankcase. Yamaha was the first two-stroke manufacturer to simplify life for the rider with the Autolube system—Suzuki and Kawasaki were quick to follow. Since the amount of oil injected varied according to engine speed, at full throttle the mixture was maybe 20:1, at idle, 200:1.

On this model Yamaha had made a major change in the drivetrain—previous YD 250s and YM1 305s had the clutch mounted on the left end of the crankshaft, but on the YM2 it had been moved back to the transmission shaft. Crankshaft clutches have several dubious qualities. First, it makes the engine wide, which might not be helpful when coping with fast corners. Two, it is harder to balance the whole engine with that heavy weight on one end. Though on the YD at the other end a rather bulbous cover housed the less weighty alternator and ignition points, giving whomever was fiddling with the ignition easy access. Third, such a design—with the clutch running at engine speed rather than re­duced as it would be on the transmission shaft—makes the clutch grabbier since there is little possibility of putting any cushioning in there. It is now accepted wisdom that it is better to have the clutch at the transmission end of the primary case.

The gearbox had five ratios, and since the input was on the left side, the output to the rear wheel on the right, it made for better balancing. The kickstarter was on the left side, but fortunately that was infrequently used, thanks to the electric starter.

A bit of history. When Frank Cooper took on the job of distributing Yamaha motorcycles in the United States in 1960, he knew that some changes would have to be made —especially in the naming. When the Japanese company first began selling its own motorcycles in Japan in 1955, the YA1 was the focus. It was a nice little 125cc two-stroke single, but the alpha­numerics were a bit of a yawn-maker. Then came the 175cc YC1 in 1956, followed by the YD1 250 a year later. While the home-market was happy with this identifying process, Cooper knew that Americans wanted a little more drama.

When he put a half-page ad for his 250 line in the August 1960 Cycle magazine, he called one the Grand Prix Sports, the off-road/lightless model the Grand Prix Scrambler, and the one with electric starter the De Luxe Twin. Then the Japanese suits took over and reverted to the old system of identification, promoting the YD3, with electric starting, and YDS2, the sporting version. But it was the introduction of the TD1 (no idea where the T came from) 250 roadracer which actually put the company on the racing map, but that is another story. Yamaha was soon thinking about upping the engine size to 305 to meet its main competitor, Honda, which had been very successful with the 305 Super Hawk.

The 250 YDS3C Big Bear came on the scene in 1965, but it was a scrambler in name only. A little bit of dirt-roading, perhaps, but that would be the limit of its scrambling ability. Street-scramblers were one of the motorcycling styling vogues in the mid-’60s, and nobody had any illusions about their intentions—paved roads.

Move forward 18 months and the YM2C 305cc Big Bear was introduced, and soon arrived at the dealers. Who had a hard time keeping them in stock, not because the buyers thought they could win the Big Bear race, but because the bike looked so darned cool. There was chrome everywhere, on the gas tank, the fenders and the two big upswept exhaust systems. Along with open chromed springs on the fork and shocks—the shocks here are not original, but are similar ones from Redwing. And, of course, a bit of bright blue—or red or black, the other colors available.

Yamaha YM2C Big Bear 305 Scrambler: 1967

Year/model: 1967 Yamaha YM2C Big Bear 305. Owner: Jeff Williams, Los Osos, California.

The engine was bolted into a full-cradle frame, with preload-adjustable shocks at the back, a standard hydraulic fork up front. A hydraulic steering damper was mounted on the fork, an indication of the bike’s intentions—off-road riders like friction dampers, not the hydraulic type. Eighteen-inch wheels used a 3.00 Dunlop Universal tire and single-leading-shoe brake at the front, 3.50 and another single-leading-shoe at the back.

This was no lightweight. With four gallons of regular in the gas tank and four pints of oil in the Autolube tank the Big Bear 305 weighed in at over 360 pounds, with the wheelbase a tidy 51 inches. Top speed was in the 80s, but riders weren’t very interested in that—too fast to be admired. Big Bear types preferred idling around town, or the campus, and let the onlookers be envious. In truth it was a perfectly adequate street bike, with those never-used off-road pretensions. And it only cost $700.

Then, several changes came in the Yamaha line-up. First, the apparent successor to the 305 Big Bear was the 350cc YR2C Grand Prix Scrambler, introduced in December of 1967 with an extra hundred bucks on the price tag and an extra 5 horsepower at the crankshaft. Second, the brilliant new DT1 250cc single-cylinder enduro machine was intro- ­duced, offering genuine off-roadability and forever changing the notion of dual-purpose motorcycle.

[This Retrospective: Yamaha YM2C Big Bear 305 Scrambler: 1967 was originally published in the October 2011 issue of Rider magazine]

Comments

10 Responses to “Retrospective: Yamaha YM2C Big Bear 305 Scrambler: 1967”

  1. HARLEY JACOBS on May 18th, 2012 6:25 am

    In the spring of 1967, I traded in by Twin Jet 100 to C L Young Appliance (washers, dryers,fridges) and bought a new blue 305 Big Bear. I was 16 and was I on top of the world. What a time. I remembered loving everthing about the bike. Especially how you could unscrew the exhaust tips and remove the baffles. what a sound, especially if you didn’t screw the tips back on. I was Paul Newman/James Garner with the Formula One sound. I’d have old men hear me coming a mile away and be in the middle of the street to stop me. When I got close, time to down shift and goose it.
    Clement, I love your knowledge, research and writing. Hope to meet you some day. I keep looking for a Big Bear to ride and park next to my Dream 305.

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  2. rob on May 27th, 2012 9:20 pm

    i own a1966 red and white yamaha 250 yds3c big bear it took me 46 years to get cne i had a black and white cne in 1974 they sound great with the popping and crackling of the bear pipes also the hollow sound when under load i would like to know how many 1966 big bears were made and how many came to north america i live in toronto canada i remember thesummer cf 1966 you couldnt go 1 block without hearing one i was 14 rob 647 237 6602 or email eatherley@rogers.com

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  3. Derk on July 30th, 2012 9:52 am

    Wow Jeff you lucky dog, that is a twin to the the one I owned at 15 and had thru out my high school years. I have looked all over and have not found one, as I want to buy one. Brings back a lot of memories!

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  4. Ed on August 6th, 2012 10:04 pm

    I am presently restoring a 1967 Yamaha Ym2c. Found one about a year ago, all complete but rusty. Driving me to the poor house in rechroming bills. But it is looking good! Another 3 to 4 months, and I will be able to park it next to my 1967 Red Honda 305 Scrambler.

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  5. dave uglem on August 12th, 2012 5:24 pm

    Had one in 1968 black. Fast for the day (I was 17 and 140 Lbs. 30hp! Zoom.

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  6. L Cranston on August 17th, 2012 1:45 pm

    Mine was blue. At 18 I was on top of the world with my 305! Drove Ft Lauderdale to Atlanta many times. It didn’t handle N Ga roads well with single cam brakes and universal tires but youthful enthusiasm overcame those issues. At 70mph it turned over 6,000 rpm. Made it to 36k miles before it was used up. Traded it in on a new XS 650.

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  7. Robert Pollock on September 7th, 2012 4:20 pm

    At 15, I bought one for $300.00 Had to push it home because it wouldn’t start, but that was just contact points adjustment. Pushing it home, going down a hill, I jumped on and rode through a stop sign. There wasn’t any other traffic except a cop, about two blocks away. My first ticket.

    I loved the bike to, but I couldn’t keep a set of plugs for more than 100 miles. Too rich, they fouled and too lean, they evaporated. I used beat Bonnevilles off the line like they were using pedals. Up to about 65 mph and then the speed wobble. The engines torque under hard acceleration would pull the rear wheel out of alignment. I kept a 7/8″ or what ever it was box end wrench under the seat to loosen the axle nut, re-align the wheel and cinch it down again.

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    paul Reply:

    I have an old ym1 bought in1966 for 500dollars. I solved the plug fouling problem. I replaced the stock coils with 6 volt automotive coils and the condensers with Delco condensers , also Champion platinum tip spark plugs. I did this in 1967 and haven’t changed a plug since.

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  8. KC Primm on January 16th, 2013 9:32 pm

    My Big Bear 305 was my first bike. I remember leaving a lot of bikes in the dust, especially all the four strokes.

    The torque was tremendous off the line and the acceleration was very exciting. It had a front “Sand Tire” with knobbies along the side edge only.

    Great first bike!

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  9. SC Dapson on December 12th, 2013 4:37 pm

    I still have my 1967 YM2C with the tank exchanged for a DS6C (green) tank and an R3 seat. I plan to return it to original look and sell it since I can’t ride it anymore. A drunk driver took off my left leg so I can’t shift on the left anymore.

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