The Magic Cylinders: Just Another Port In The Storm

Then Buster said something that floored me. Would I like to borrow a spare set of Kenny’s 250 cylinders?

(Author: Jerry Smith)

All Rights Reserved.

In 1976, $10 worth of gas would get you halfway to the next state, not just halfway to the next gas station. A new Yamaha TZ250 roadracer cost $1,495, and came with treaded Yokohama “roadrace” tires everyone called “rim protectors”. I was working at a parts distributor in Marin County, California, making all of $4,000 a year, living in an ant farm of an apartment on the canal in San Rafael, subsisting on ramen noodles and hot dogs so cheap the local seagulls wouldn’t touch them. Entire weeks went by when I had no more than five bucks in my pocket at any time.

So of course I went to Daytona that year.

I had a Bell Star helmet, a set of leathers that had been made by a part-time tailor named Donald McDonald, and gloves I’d found at Orchard Supply Hardware. My spare-parts bin for the TZ held a box of spark plugs, a clip-type master link, a few sprockets, and a roll of safety wire. I loaded it all into a van alongside a tattered RD350 I was going to ride in the production class, threw a sheet of plywood on top of the bikes to sleep on, and hit the road.

It took us about 55 hours of non-stop driving to get to the track where two other racers and I had pooled our resources and rented a garage in the pit area for the week. Next to us was the Yamaha team, where Kel Carruthers was looking after Kenny Roberts’ bikes. Kenny’s dad Buster was there, too. So was Ray Hook, who made Blendzall two-stroke oil. Blendzall was the oil of choice back then. Rumor has it the Yamaha guys dumped out the oil in the Yamalube bottles displayed prominently in their garage and filled them with Blendzall when nobody was looking.

Kenny, Buster, and Ray were all from Modesto, California. The guy I was working for at the time, who I’d come to Daytona with, was also from Modesto, and he and Ray were buddies, as were Ray and Buster, so there was occasional coming and going between the Yamaha garage and ours.

That was the first year the AMA required mufflers on roadracers. The stated reason was something along the lines of “less sound, more ground,” although how that applied to a superspeedway like Daytona was a mystery to one and all.

When I arrived at the track for the first day of practice, walking around the pits I saw three or four brands of expansion chambers for sale with built-in mufflers. They’d been tuned to work with them, and subsequent lap times showed they gave up little or nothing to the unmuffled pipes everyone had run last year.

Strapped for cash, I had hacksawed the stingers off my expansion chambers and replaced them with generic weld-on mufflers packed with fiberglass. Even I figured this wasn’t going to work very well, and I was right. I spent a couple of days trying to get my bike going as fast as it did the year before, with no success.

One afternoon, while I was moping around the garage between practices, Buster Roberts dropped by. Buster Roberts is Kenny Roberts’ father. He asked how I was doing, and I told him about my lack of speed, and my muffler problem.

Buster Roberts and Jimmy Filice, Laguna Seca Raceway 1997.
Buster Roberts and Jimmy Filice, Laguna Seca Raceway 1997. Note cool-ass belt. Dean Adams

Buster and I surmised a bit, and one or the other of us suggested my cylinders might have been ported too radically (or perhaps the word was inexpertly) to work with mufflers. That was entirely possible, since I did my own port work back then. But I only had the one set of cylinders anyway, so I was stuck with them.

Then Buster said something that floored me. Would I like to borrow a spare set of Kenny’s 250 cylinders?

You know that scene in the western where the bad guy walks into the saloon and the piano stops, and everybody’s head swivels toward the door? That was pretty much the effect Buster’s words had on everyone standing nearby.

I was so surprised that I said something I meant to come out more or less like ‘Why, yes, Buster, I would, thank you’, but probably sounded like I was choking on a chicken bone. Buster went next door and a minute later came back and handed me a box containing a cylinder block for a TZ250.

You have to understand that in those days Kenny Roberts was a God. So was Kel Carruthers, who tuned Kenny’s bikes. Between the two of them, they were knocking American road racing on its ear. Rumors abounded about unobtanium parts, magic ignitions, port timing developed by NASA-everyone was certain Kel knew something nobody else did, and that was one of the reasons why Kenny and his bikes were so damn fast.

So when Buster handed me that cylinder block, it was like an angel handing Indiana Jones the Ark and saying, “Go ahead, take a peek inside.”

I opened the box and lifted the block out. The first thing I noticed was the ports. They were rough cast, not like the ones in my cylinders that I’d labored over for hours, smoothing the walls with a Dremel tool and jeweler’s files.

I grabbed the dial caliper out of my toolbox and measured the port heights and widths. I knew the stock dimensions by heart, and one by one they came up on the dial.

By now I had an audience. “Well?” someone demanded. “Stock,” I said, shaking my head. “They’re stock.”

I thanked Buster for his generosity but decided to stick with my own cylinders. My race didn’t go that well. I qualified at the back of the first wave, and finished downfield from there. My bike ran poorly, and by the time I saw the checkered flag I was more than ready for the race to be over.

Kenny Roberts’ day didn’t go that well, either. A tire failure in the 200 caused him to crash, and Johnny Cecotto ran away with the race. I snapped a picture of Roberts after the race, a minute after he climbed off the bike and pulled off his helmet, exposing the strips of duct tape he used to keep his hair out of his eyes.

After that race our career paths, Kenny Roberts’ and mine, diverged. I raced in the AMA for another year or so, then hung up my leathers and eventually became a writer. Kenny Roberts went to Europe, kicked a lot of European road-racing ass, and eventually became a legend.

Years later, when I worked for Cycle Guide, I got a chance to interview him for an hour or so at Willow Springs Raceway. I meant to ask him about that cylinder Buster handed me back in 1976, but I never got around to it.

To this day I can’t say for sure whether Buster had picked up the wrong box, or if he was just offering me a new stock cylinder block to replace the one I’d butchered.

But I suspect the truth is that he picked up the right box, that Kenny Roberts ran out-of-the-box cylinders on his 250. After all, why even bring stock cylinders to a race if the ones on the race bike were ported? Why not just bring another set or two of ported cylinders?

I’ll probably never know. And you know what? I don’t care. In fact, I think the reason why I didn’t ask Kenny when I had the chance is I like my version of the truth. And you have to admit, it makes a helluva good story.


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