Vintage Motocross Racing

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John Stein (983) fights for position with former AMA star Scott Burnworth (8).
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Airborne: A stock 1974 Yamaha MX125’s suspension is most suitable for play riding, but properly motivated it can still get up and fly.
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Stein makes camp at Marty Tripes’ inaugural Carlsbad Reunion at The Ranch, a 700-acre offroad motorsports park in Anza, Calif.
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Shapely and powerful Ossa Stiletto TT is also buzzy; it shed both tank badges at Sonoma. Race Tech fork mods and Works Performance shocks were huge improvements.
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Shapely and powerful Ossa Stiletto TT is also buzzy; it shed both tank badges at Sonoma. Race Tech fork mods and Works Performance shocks were huge improvements.
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Shapely and powerful Ossa Stiletto TT is also buzzy; it shed both tank badges at Sonoma. Race Tech fork mods and Works Performance shocks were huge improvements.
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Experience and expert advice helped Stein turn Yamaha’s proletariat 125 motocrosser into a formidable vintage weapon. Suspension and power improvements were critical.
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Experience and expert advice helped Stein turn Yamaha’s proletariat 125 motocrosser into a formidable vintage weapon. Suspension and power improvements were critical.
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Experience and expert advice helped Stein turn Yamaha’s proletariat 125 motocrosser into a formidable vintage weapon. Suspension and power improvements were critical.
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The author and the Yamaha MX/YZ125 after a muddy Carlsbad Reunion moto.
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The Stiletto TT was built for dirt-track racing, but a 21-inch front wheel and a longer Stiletto MX swingarm help prepare it for motocross.
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The all-in cost for both bikes approaching the two-day Sonoma event soared to $9,916.

Perhaps it’s some genetic deviancy, but the challenges of problem-solving and mechanical resurrection that old bikes offer are more than just fun — they’re irresistible.

So it’s little wonder I chose a pair of vintage 2-strokes, rather than nice new machinery, when I decided to pursue a national motocross title. The notion that it could be done cheaply was added incentive. But would it? Only trying would tell.

Affordable beginnings

You couldn’t start much lower than a 1974 Yamaha MX125, bought from a Craigslist ad for $700, for the American Historic Racing Motorcycle Association’s (AHRMA) Sportsman 125 class. However, one ride revealed the stock suspension was intended for flyweights doing laps in a dirt lot, as both ends bottomed at almost any provocation. Still thinking economy, I installed spacers to bump up the fork-spring preload and found a half-inch longer pair of shocks for $45 on eBay, and then tried it again at a local race. It was hardly any better. Luckily, a call to vintage motocross racer and Yamaha medicine man Dave Rymal located a perfect MX360 fork and triple clamps, a vast bolt-on improvement, for $200. I also installed a new piston and ring, points and condenser, Uni Filter, tires and chain for about $250.

Motor racing artist Hector Cademartori and I headed to Arizona Cycle Park for AHRMA’s first western national of the year — one of seven I had targeted. The little Yamaha was better, but it still bottomed on hard landings and the shocks and seat were punishing. The engine was also down on power in the 125 class and especially in the 50-plus age group class, which was populated by 250s and 400s. Still, the little bumblebee managed to win three of four motos and take both overall class wins for the day, trouncing much bigger CZs, Maicos and the like. Not bad for a total investment of less than $1,200. Maybe we had something here.

We left Arizona on a high note, inspired to develop the bike further. In the weeks before the AHRMA round at Sonoma Raceway, I yanked the front end and sent it to Race Tech for $515 worth of Gold Valve Cartridge Emulators, new springs, seals, fluid and labor. I also engaged Works Performance to build a $445 pair of steel-bodied Gasser shocks with dual-rate springs. The stock seat, with its tired 37-year-old foam, went to AMS Racing for a full rebuild, a purposeful inch taller to improve ergonomics, for another $175. SportCycle Pacific also welded on a $30 pair of footpeg extensions.

All of this improved rideability but not the problem of being outgunned to the first turn. So while the chassis was apart, Rymal also found a donor YZ125 engine for $100 and had it shipped to Scott Clough Racing. SCR rebuilt it with a new ProX connecting rod kit, a new piston, bearings, seals, cylinder porting, increased compression, a tougher clutch and a larger Banshee reed valve for $1,100. Since the YZ donor engine lacked an ignition system, Scott added a killer $528 PVL unit from Penton Racing Products — the go-to ignition for vintage bikes. The engine would now need race gas at $13 per gallon rather than pump gas, but at least it didn’t use more than 2 gallons per weekend.

The final additions were grippy new Dunlop MX51 tires, new tubes, a Yamaha GYTR racing chain and a 12-tooth front sprocket at $230. Total cost for the 125 ready for Sonoma: $4,318. Ouch! Apparently, the adopt-a-stray-dog ideology is not all that cheap, since you can buy a decent used modern bike for less. But after having raced the 125 bumblebee successfully in meeker form, I could hardly wait to get to the next event.

One is never enough

One lesson learned at Arizona was that riding a 125 against 250s and 400s is masochistic. You’ll always reach the first turn toward the back of the pack, and although your lap times might be better than your rivals’, the entire race will be spent eating roost and making cutthroat passes. Which is why bike No. 2 crept into my life, through a random contact on Mark Holloway’s excellent Vintage Swapmeet. It was a bright-orange 1971 Ossa Stiletto 250TT, an infamously short-fused Spanish scrambler. I’d always wanted to race a Stiletto, and for $999 it seemed like a good solution to the age group/horsepower dilemma.

While the Stiletto chassis was okay, the engine cases were cracked behind the countershaft sprocket, a known trouble spot according to Ossa specialist Keith Lynas. One crankshaft flywheel was also cracked. So Lynas got busy building up a new engine for $2,700 — which included replacement cases — while I sent the fork to Race Tech for $505 worth of Gold Valves, new springs, fluid and labor, and ordered a second pair of Works Performance Gassers. The wheels revealed frozen spokes, so I picked up a one-owner Ossa Pioneer enduro bike for $250 and transferred its identical wheels to the TT. Some cad plating, a second pair of Dunlop MX51s and tubes, a race-spec Yamaha GYTR chain, comfy TAG grips, another AMS tall seat rebuild, and new cables and petcocks from Ossa World added $699 to the Stiletto tally for a total of $5,598 — clearly more than its street value.

My all-in cost for both bikes approaching the two-day Sonoma event had soared to $9,916 — more than a new 450 4-stroke! — but I headed toward San Francisco with high hopes. Event organizer and 500cc world champion Brad Lackey and I had met decades earlier while participating in Cycle magazine’s benchmark motocross fitness shootout, “Running at the Human Redline,” which he won over Jeff Ward and Mike Bell, with me surprisingly in fourth. At Sonoma I was glad to find Bad Brad as friendly and upbeat as ever, and his course was a long European scrambles favoring the steep natural terrain rather than dozer work.

Practice showed the Yamaha MX/YZ hybrid to be a monster, relatively speaking. The new SCR engine made explosive power and the close-ratio gearbox suited the power spread perfectly. But the Yammie, now with a taller ride height and seat, and less flywheel, became tricky to launch, and fanning the clutch in first gear yielded big wheelies. But once hooked up, the little beast was a rocket — and the better seat and pegs dramatically improved comfort.

Plus, the suspension went from terrible to terrific, meaning the MX125 could now soak up anything this pilot could ask of it. However, the Stiletto was as different as you could imagine. While powerful, it also felt long, heavy and slow-turning by comparison, which was rather disappointing considering my long-term Stiletto fetish. But the combination of Race Tech fork upgrades, Works shocks and new seat made it eminently raceable, instead of merely survivable.

Highs, lows and body blows

A promising weekend hiccupped as the sprocket bolts on the Yamaha’s rear wheel backed partway out during the first moto, causing the sprocket to wobble and the chain to jump ship. We still managed a second in class, and the MX/YZ125 proved it had the measure of the other 125s. Rider error then jinxed my maiden Stiletto race, as its long-travel levers thwarted quick braking while tailing the leader on lap one. My front tire touched his rear tire, high-siding me in front of the pack. Two bikes ran over me, including a Maico that stopped above me, its engine screaming while its rear tire clawed into my leg. The corner workers seemed shocked when I got up, restarted the Stiletto and salvaged a sixth-place finish.

The second round of motos wasn’t much better, as I had tightened the Yamaha’s chain but hadn’t yet caught the sprocket problem. While leading the second 125 moto the chain jumped again, I reinstalled it again and finished second again, for second overall. Only that evening did I discover and tighten the loose bolts, the true cause of the problem. But at least the Stiletto earned an overall win in my big age group field to finish the day in third overall. I was still looking okay in the points.

Day two of the doubleheader was not to be. At 2:30 a.m. I awoke to throbbing pain in my left hand, whacked in the pileup and now swollen like a microwave pocket pita. I took two Aleve and paced through the dark pits with an ice pack to little improvement. Later I winced through practice and, conceding that I would be a hazard in the motos, withdrew and drove home.

Three months until the next California national at Glen Helen allowed plenty of time to heal, prepare, ride modern MX and anticipate the remaining rounds. My friend Bill Masho, a noted photographer and bike restorer, joined me with his newly finished Ossa Phantom for Marty Tripes’ inaugural Carlsbad Reunion at The Ranch, followed by AHRMA’s Glen Helen round. Tripes’ event at Mark Peters’ new Carlsbad-replica track was fun, and Masho and I both scored 1-1 finishes in our classes — he on the lovely Phantom and me on the Yamaha 125.

Sunday at Glen Helen started great. Racing on the amateur track meant no really big jumps, just lots of uphills and downhills, a few ruts, and pockets of mud and dust. The Stiletto excelled in the first moto, scoring its second national win. The Yamaha shot into the lead in its first 125 moto as well, clearly feeling its oats with a new $57 GYRT chain and $21 Sprocket Specialists rear sprocket securely bolted on. At least there’s something actually cheap on this bike!

However, less secure was the front brake cable, which freakishly snagged one of the triple-clamp bolts on a steep climb. The front brake locked instantly, savagely throwing me over the bars and to the ground. I yanked the bike upright and continued, determined to finish strongly. But the gods scolded me again as my shoulder quickly stiffened. I pulled into the pits and headed for the EMTs, who confirmed a broken collarbone. At least it was nice and cool in the air-conditioned ambulance. On the way home, Masho and I agreed that buddies should help buddies by safety-checking each other’s bikes. Neither the AHRMA tech nor I had caught the cable problem — but maybe a third set of eyes would have. Scuba divers use the buddy system, and riders should, too.


Eight weeks later, the AHRMA nationals concluded, leaving me sixth in Sportsman 125 and ninth in my age group, with seven moto wins and three overalls, including at the separate Carlsbad Reunion. Not the No. 1 plates that I wanted, and hardly convincing value for the $10,861 worth of bikes, component upgrades, race gas, travel and entry fees during the year. Yet despite the cost and crashes, I maintain it was a good try; developing the bikes was terrific fun, and I learned more than I could from any textbook. I’ve healed well and I’m back riding again after my injuries. And then, there’s always next season. Lord knows I have the bikes for it. Even if they’re not exactly cheap, after all. MC

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