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It takes a Village to raise a racebike…

Little Scramblers grow up to be AHRMA racers!
Little Scramblers grow up to be AHRMA racers!
AHMC

“Back in the day…” (1974) I was a one-man racing team; owner, tuner, builder, sponsor, rider and transportation manager. Although the SoCal racing organizations had been active since the 1950s, road racing was a relatively small sport without massive factory funding, unless you were on the highest echelons of the sport. Working on a very small budget, I bought a brand new 1974 CB125S1 from the local Honda dealer, re-laced the rear 17” wheel with a narrow 18” rim and installed a set of Yokohama racing tires in 2.50x18 sizes (there were no 17” racing tires back then), tore the engine out and installed some wicked Yoshimura racing parts (cam, piston and crankshaft), ported the head, added some folding footpegs, a set of number plates and went road racing in the 125cc Production class.

In the 1970s, there was a plethora of small-bore street bikes from various countries other than Japan. I recall a Bultaco Streaker and a Montgomery Wards Benelli showing up at times, along with a Suzuki 125 Stinger, Yamaha 100 and 125cc twins, a bare-bones rotary-valve Kawasaki 90 and later in the year, a DKW 125 “Enduro,” which ruled the class in the following year, ridden by John Ulrich. I was riding in both the CMC (California Motorcycle Club) and the AFM (American Federation of Motorcyclists) organizations, which shared race tracks and split the events up so that avid racers could attend club events from either club. These were the heydays of racing in California, as there were racetracks at Orange County, Carlsbad, Riverside, Ontario, Willow Springs, Laguna Seca and at Sears Point Raceway.

Over the years, encroachment by builders and the lack of racing revenues for many tracks (plus the increasing value of land) lead to the demolition of many of the SoCal venues, replaced by condos, strip malls and single-family homes. The rich heritage of Riverside, Ontario, Orange County, Carlsbad racing events is all but a faint memory to those who were racing back in the last part of the 20th century. For the most part, the club racing was done at a very low $$$ level for many racers. Some received sponsorship from local bike shops and a few even got some factory level sponsorship, but you never saw their names or the results in the local daily newspapers. Racing was, for the most part, an individual hobby and racing was as much about seeing “racer family” members a few times a month, than it was about winning championships and securing lucrative contracts.

There was more than a little mutual support available among the attendees. Lose a bolt or nut or need a spare spark plug or a little more oil? You could usually get some help from someone in the pits with a little bit of pleading or a few bucks, if the item was expensive. Often, money didn’t change hands as long as the part was something that could be returned at the end of the day. I recall giving a rider a spare self-locking nut that was in my box of spares as his had spun off of the XS650 Yamaha twin bone-shaker that he was thrashing that weekend. That particular incident happened at a racetrack just outside of Las Vegas, where there were no options of running into town to pick up a spare piece of hardware. I was glad to give him the nut, as his racing weekend was going to be over without it.

We didn’t have texting, smart phones or internet communications back then, so we relied upon face-to-face meetings with actual conversation involved. When something broke in a major way you were done for the weekend, in most cases and you might spend much of the next week ordering or finding the needed parts to get the bike back to racing trim once again. Most classes and a variety of makes and models, so borrowing spares was not always an option. Most racers, like me, only had a few extras at the track, like spare inner tubes, spark plugs, oil and perhaps some brake and clutch levers, in case of a minor get-off incident.

Today, however, there is a rather large niche of racing devoted to a series of inexpensive (at least in the beginning) machines that can launch an interested rider into a genuine racing experience without having to mortgage the family home. Originally called Group W racing, which began up in the Pacific Northwest (WA and OR), the series began with a handful of riders who had picked up ratty CB/CL160 street bikes, which were stripped down to the basics and turned loose in their own little racing division. The Group W racing/Bateman Racing sites haven’t been updated since about 2008-9 it appears, as the proponents of the class are probably too busy racing and supplying parts for aspiring small-bore racing enthusiasts. Currently the most productive place to share information is the F-160 forum on Yahoo, which is the current storehouse of pooled knowledge and racing parts/bikes.

The original 160cc based bikes slowly gave way to the 175cc 5-speed “sloper” engines, which in turn included the “vertical” CB/CL/SL175 models ending with the 1974-75 CB/CL200T models. Despite the orientation of the cylinders, many of the engine parts can and are interchanged between all related models. The wrist pin size on the CB200T engine was increased, so that limited some of the mods associated with that engine configuration, but lots of other parts can be interchanged/swapped. Pertronix ignition modules replace the ignition points and condenser original point plates, ensuring nice even sparks all the way past 12k rpms.

These engines all came out with 360 degree crankshafts, alternating a firing stroke from side to side each revolution, however that amount of mass (pistons/rods/crankpin) spinning up over 10k rpms weighs heavily on the crankshaft bearings, often resulting in crank failure after excessive amounts of racing events. The big-bucks trick is to press the crankshafts apart and turn the journals to make it a 180 degree firing motor. A new camshaft has to be ground as well as a dual ignition system. That much work can yield some impressive power and reliability at super high revs, but some of the bottom end torque is lost. Fortunately, the 160s can be retrofitted with a 5 speed transmission to help them overcome some of the horsepower deficits for the low-budget riders.

There is a fierce competition in this class now, through the AHRMA racing organization. Grids of 40-60 riders line up for a chance to challenge themselves and each other at some of the nation’s premier venues, like Road Atlanta, Miller Motorsports Park, Barber Motorsports and Daytona, FL, with a couple of West Coast events at Sears Point (Sonoma) and the venerable Willow Springs Raceway out in the high desert. There were ten events scheduled this year, spanning the width of the nation.

The F-160 forum is sometimes quiet and sometimes lively with action and activity among the members, old and new. When someone has a need for a part or service or just a ride out to an event, the connections can be made almost immediately via the internet now. This brings me to the origins of this story today…

I received a text message AND a voicemail message from a young rider who had just fired up a freshly-built 175 “sloper” race motor and was dismayed to discover large quantities of oil smoke emanating from the 2:1 exhaust pipes. With the Miller Motorsport racing event coming up this weekend, there was desperate wrenching going on to pull the motor, tear down the top end and discover the cause of the excessive oil consumption. In this case, one piston had a broken piston ring, which caused no damage to the cylinder walls or piston, but was definitely in need of replacement. Unfortunately, American Honda doesn’t stock the five sizes of piston rings for a 1967-68 CL175K0 anymore, so the hunt was on to find the correct .50 oversized piston rings.

My approach is always to find one of the Honda parts sites which offer microfiche images of the parts and part numbers, then do a web search for the part, using the Honda part number. Sometimes, this results in a lot of eBay auction listings and more online microfiche listings, but few parts. If the Honda part number has been changed/superseded, you can then upgrade the search terms to include the replacement part number. I recently found that the old CB350 piston ring sets, which used a one-piece oil ring, were superseded by an updated XL175 piston ring set that uses a more modern 3-piece oil ring set. These are always an improvement for building engines today and even the little Honda 90 pistons/rings are using the newer parts now.

Because of the bore size and application of the 175cc pistons, there have been no such upgrades in the way of pistons/rings. Honda did, however, change the way the produced the piston rings, going from a chromed top compression ring on top, with two cast iron plain rings below to an all-chromed piston ring set, which have better durability but a slower break-in period. In this case, the request was for any .50 oversized 175 piston rings available, preferably close to Los Angeles area.

Normally, I don’t have a lot to do with small bore bikes, concentrating upon the 250-305s keep me plenty busy, as it is. However, a couple of months ago a Honda friend shared my name and number with a gentleman who lived out in the East County are of San Diego, who then called me to offer a “batch” of pistons/rings and other misc parts for vintage Hondas that he had been sitting on for many years. I took a chance and drove out the 30 miles to pay a visit and came home with the back of my PT Cruiser full of many small red Honda parts boxes. There were pistons/rings for 50cc Cubs, Z50s, S90s, CB92s, SS125s, CB160s, CB/CL175s, CB72s, CB350s, CB900s and all manner of other models in between. I was able to sell off a good chunk of them through word of mouth and on eBay auctions, but the 160-175 rings were still in plentiful supply. When I checked my stock I discovered 2 sets of 235 code 175 piston rings in the .50 oversize requested. A few emails and calls back and forth made the time/distance issues apparent. If the rings could be delivered today, then the bike could be worked on and fired up before tomorrow. There were actually other sets of rings being shipped in from out of state, but none were this close to the LA owner. After dismissing talk of driving down and back to pick them up, the Plan B was to take them to the local Greyhound Bus station and have them run up to the LA station in a matter of 3-4 hours. That task entailed boxing up the little ring sets and labeling the package for delivery, then jumping into the car for a 14 mile trip to downtown San Diego for the hand-off to Greyhound.

It was nearing 2PM when the package was checked into their system, but with buses running every hour to LA, the estimated delivery time was going to be a bit after 5PM. Luckily, this owner worked downtown and was off work by 5:30. Rushing over to the Greyhound terminal, the package was awaiting pickup and the contents were a delight to the beleaguered racer to be. With parts in hand, the bike was in the process of being reassembled by mid evening with an aim to fire it up before the end of the night.

Sometimes a combination of luck and serendipity come into play when a desperate situation arises in the midst of prepping a race bike for an upcoming event. I’m not sure who was the link in the chain that brought the piston ring request to me this day, but it was part of that whole village of like-minded 160-175 racers who band together to help each other get out to the track and compete to the best of their abilities (and budgets). I was glad to be able to supply the much needed piston ring set in a timely manner, under circumstances where a whole day might have been lost waiting for parts to arrive overnight from other surrounding states. It was the right request at the right time with the right people involved in pulling off the fulfillment of a dire need for just the right parts to make a rider’s dream of competing at a faraway track come true. It’s nice to be a member of the Vintage Honda village.

This whole situation made me revisit a number of similar incidents that occurred when I was “being a racer” back in the 1970s. At the end of the 1974 season, my little 4-stroke Honda single and I had captured the 125cc championships in both the CMC and AFM clubs! That’s a nice memory to treasure.

Bill “MrHonda” Silver