Yamaha TZ750: Meeting The Monster

From roach to racer in three easy, fun-filled days. (Ha!) We go butt-to-saddle at Daytona with the most notorious and successful roadracing motorcycle of the 1970s--Yamaha's TZ750

By: Patrick Bodden, Mitch Boehm, Photography by Tom Riles, Catherine Brennan

Fact is, racing rsum or not, many a TZ750 fell into less-than-expert hands, meaning they didn't have much exquisite workmanship lavished on them. Nomatter. The TZ750, like its smaller brethren before it, was so inherently good and so naturally cooperative that, as long as the bike was reasonably well bolted together and no one went crazy with ignition timing and carburetor jetting, would go like fury and do so for a long time. Parts were readily available from local dealers and, as long as they were replaced as Yamaha prescribed, didn't often fail. Many a ratty TZ750--Miles Baldwin's and Richard Chambers' bikes come to mind--would allow a motivated and capable second-echelon privateer to upstage the more elegant (read: factory) front-runners.Bigley had had his hands full trying to prep two TZs--Lentz's bike and Bigley's own Spondon-framed racer--and the preparation he'd done wasn't meticulous. It was the rough-and-ready type that had sufficed all those years ago during the TZ's heyday. Problem was, there hadn't been enough preparation. The Lentz machine is a long way from something Boehm or anyone else would consider an acceptable risk on the racetrack. There's a lot of work to do, some evident and some yet to be discovered.

This hadn't been part of the bargain when Boehm presented me with his latest Daytona scheme a few months earlier. It was supposed to have been Heritage Relaxed Racing this time; just show up, look the bike over, check the tires and spark plugs, and let's have a go at it. But here it was, take it or leave it. Might as well get on with it, I thought.

Boehm: My plan going in, which I communicated ad nauseum in the lead-up to Bike Week, was simpler--and therefore potentially less angst-generating--than many of our previous vintage-racing adventures. Bigley had told me over the winter the TZ would be "basically ready to go" when it arrived in Daytona. He'd spooned a fresh set of sticky Avon vintage tires onto the bike's old sand-cast mags, and although heavy snowfall in New Jersey kept him from bumping the bike off and making sure it ran, he told me not to worry. Because AHRMA didn't have a class for what's arguably one of the most historic racing motorcycles in the world (highly ironic, considering it's the American historic Racing Motorcycle Association), I planned to run the TZ in the Championship Cup Series' Formula 40 event, which allowed any racebike but was limited to riders aged 40 and older.

Bodden: When you're in trouble you turn to your friends. And if there aren't enough of them, you draft innocent bystanders. Heritage Racing partner R.L. Brooks is a long-time friend who's helped me through more than one Motorcyclist vintage-racing adventure. He and I make new friends on the spot--Phil DiGiandomenico (whom we'd met briefly a few years before, and father of Jimmy and Tommy) and congenial but unsuspecting TZ750 racer (and Brit) Mark Middleton, to name just two.

We size up the situation from clues provided by Bigley and our own sleuthing and chart a course of action. Someone detects excess fork oil on the tubes right away, so Boehm is wise to at least one problem. No big deal. Bigley has new seals, so R.L. and Phil D. get busy replacing them. As is so often the case with seemingly minor problems, unforeseen snags ground our resolution to a halt. The guys aren't any sooner into the job than they're stalled by the Allen bolt holding one of the fork legs together; its internal hex is no longer hexagonal and the bolt isn't responding to wrenches or cusswords. It's off to locales with better weapons--DiGiandomenico's nearby Daytona garage--where extracting the bolt proves fairly easy, even if it means destroying it in the process. Of course, it isn't a garden-variety piece--it's of an exotic thread pitch/diameter, and much running around reveals that a replacement isn't to be found in all of Daytona. Back at DiGiandomenico's home machine shop, a different-style bolt has its head turned on the lathe and a slot sawed into it to substitute for a hex. We're back in business. A one-hour job takes two capable and resourceful technicians an entire day.

Meanwhile, I'm working through my own misery. Carburetor synchronization, in particular, seems either interminable or impossible, I can't decide which. This thing might be a legendary motorcycle, but its carburetor linkage--four individual cables from throttle to carburetors--is becoming a legendary pain in the ass. Get three just right and I run out of adjustment on the fourth. Get four more or less OK and, if I move the cables a bit reinstalling the fuel tank, the carbs go out of sync again. Finally, when everything seems reasonable, I discover a crack in the top half of the throttle assembly. Bless his heart, old Bigley (working feverishly on his own TZ) just keeps the parts coming and offers up a replacement for the cracked piece. The new part installed, I check carb sync for the thousandth time and pronounce it fine.

As the day rolls by I keep finding things to do or fix. Racebikes are like infinite sponges of time and resources. All done (or so I think), I step back, admire how simple it all looks, and wonder how preparation--and replacing a few parts--could possibly take so long. Of course, there are other concerns, such as, would the bike be safe for Boehm to ride? At this point I'm not sure.

Boehm: By this point I'm horribly frustrated. We'd planned to run the bike in today's informal Team Hammer practice so I could get accustomed to it and the revised, much-tighter Daytona circuit. Not a chance. And the way things are going, getting any practice the following day looks iffy at best. Not a good start.

Bodden: A Daytona day has come and gone. Boehm announces quitting time (with help--via threats--from the ear-bleed PA system) and herds the crew to the local Mexican eatery, the Cancun Lagoon. A veritable food fiesta ensues, the first of three consecutive such sorties. The fare is acceptable, as are the margaritas (so I hear), some of them doctored with what looks like blue toilet bowl freshener. The more everyone drinks, the better everyone pronounces the food. By evening's end we could have substituted linoleum for taco shells and Boehm & Co. would have pronounced them mucho splendido.

By Patrick Bodden, Mitch Boehm
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