Rider: Eric Tucker #22
#C15 FSR 156 - C15MX.ET.WCBR.1088
1965 BSA 250cc Model C15 Scrambler

Built & Modified for Motocross Competition.
Owned and Raced 1978-1998 by Eric Tucker.

Sponsored by West Coast British Racing, Livermore, CA.

C15 MX story – Part 1
, By Eric Tucker
Some time in September 1985, Mike reminded me about the second
Annual Dick Mann Vintage Dirt Bike Rally which was coming up on Sunday, October 20.  I had a pile of various C-15 and B-25 parts lying around and I got a hankering to build some of it into something to race in the motocross event at the Rally.  There were only about four weeks until the Rally but I felt confident that I could get it built and running within this schedule.
I had what I believed to be a good engine, and the one to have if any for this purpose – a 1965 C15-S “scrambler” motor with the “side mounted” points (instead of that silly little Lucas distributor behind the cylinder) and the slightly beefier transmission and starter gear.  After checking it over, cleaning it up and assembling it, I put it into a BSA-made Triumph TR25-W frame, which was essentially identical to the 441 Victor frame and very similar to the older C-15 off-road frames. 
The rear wheel I used was a narrow-brake quick-change BSA with a W-3 18” rim laced to it. The trick here was I needed a sprocket for a #428 drive chain to work with the only countershaft sprocket I had. I found a nice aluminum sprocket, 52 teeth as I recall, and went hence to Orchard Supply Hardware and bought a fly-cutter. After carefully lining the sprocket up on my drill press and cinching it down I bored the ID of the sprocket to fit the BSA brake drum flange. It worked – the sprocket fit nicely with practically no runout.
I worked out other details, too – like mounting the SuperTrapp silencer/spark arrestor to the C-15 pipe (effected with a short, bent piece cut from a VW header). I fitted a TR-25W oil tank, its side-cover Oddie clips being ground off to simulate a later Victor style tank (I really didn’t like the B-25 fiberglass oil tank anyway), and got the oil plumbing and ignition wiring done.
With the Rally less than a week away I still didn’t have a front wheel.  That is to say, I had one I didn’t want to use; an 18-incher from an early BSA B-25 with a street tire on it.  Somehow I’d gotten it into my head that a 19-inch rim would be the “period” setup since a lot of the pictures I’d seen of off-road events from the early ‘60’s seemed to show front wheels just perceptibly larger than the rears, usually shod with what were called “trials” or “universal” tread tires.
So I unlaced the drum, painted it and hauled it over to Chris Quinn’s Wheel Works. Chris sold me a 19-inch 40-hole rim, an ancient Dunlop knobby, and some spokes.  He let me use his spoke threader and wheel stand to build the wheel and his truing stand to get it round and straight.
Now I had a roller, but less than two days to make it a runner. I got the rest of the bike buttoned up with a stock B-25 fiberglass tank, a B-25 steel rear fender with the taillight holes filled with glass cloth and epoxy, and a low-mounted (again, for that “period look”) plastic front fender originally from a Yamaha XS650.  I painted the fenders Ford Truck Medium Blue to match, more or less, the blue and white B-25 tank. One day left, now. I managed to get a reasonably healthy spark out of the infamous Lucas “Energy Transfer” ignition system, and borrowed the 1-1/16” Amal Monobloc carb from my street B-40. A splash of gas in the tank from the Shell station around the corner, a little push on the carb tickler button, a tentative push on the kick start lever, and…
…LIFE! The thing started on the first kick. Thrilled, I snicked it into first and took my first ride, back and forth on the community driveway for the row of duplexes where I lived at the time.
It’s now about 2:00 PM the day before the Rally, and I thought a shakedown ride was in order. I decided I’d try to get it over to Mike’s shop by riding along the defunct railroad tracks, which passed through both Pleasanton and Dublin.  With no troubles, I made it – but Mike was on call at that time driving a tow truck and had the shop closed! Oh well – so I started doing a few “practice” laps in the ad hoc track in the then-vacant field behind Mike’s shop. A couple times around, and I see Mike driving up. I think he was surprised to see me, since none of us were really sure that I’d have the bike ready. But ready enough it was, and we loaded it on Mike’s trailer with his Honda SL-100 and his BSA B-50.
Above: Practicing on the C15 behind WCBR 1985.
Below: #22 Eric Tucker cases #33 (CZ) Jim Keeton at Gambonini Ranch 1986. Eric won his class.
Above: Eric shows off his hardware!
Sandhill MX 1989; #22 Eric on the now modified C15, #2 Michael Moore on the WCBR-Ducati 250, #21 Mike Green's C15.
Right: #22 Eric Tucker (Premier-Lightweight) cases #91 Fred Mork on his ESO (Premier 500) at Sandhill 1990.
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