The Honda CB350/CL350/SL350 production run saw about a half a million created and sent to north America. This makes these Honda twins the most popular, highway worthy, motorcycle ever produce by any manufacturer. Since then, the one manufacturer to come close was Kawasaki with their EX250 (250 Ninja) which has recently been upgraded to a 300cc version, which wiped out their interchangeability for engine parts, and has disqualified their ability to count both the 250 and 300 in the same category.
The 350 Hondas also represent one of the most reliable, even referred to as “Bullet Proof” by those who have owned and race them in vintage motorcycle racing. As such, many manufacturers have continued to support their parts needs more than any other motorcycle in history. This quantity factor also makes them the most “parted out” motorcycle with these used parts available on eBay for the lowest prices of any vintage motorcycle. A fairly accurate guesstimate of the number of 350’s parted out each year is the rate of 250 to 750. The bikes are readily available as “barn finds” and “parts bikes” in their non-running states. Depending on their condition, they are either parted out or resurrected after decades of neglect.
CB350, CL350, and SL350 are so similar that Wikipedia has only one entry for 350 Honda information
Retailers like Sirius Consolidated Inc. offer more that 250 new parts, tools, and manuals for the 350 twin and are continually having more diminishing parts manufactured by suppliers as they prove to become rare and in need. http://www.siriusconinc.com/search_result.php?make=1&model=cb350&part=&partno=&x=27&y=13&search=search
At the time of writing this article, eBay had 18,783 ads for CB350 alone, then there was 11,249 ads for CL350 and 7,145 ads for SL350s. Yes, many of those were duplicated for all three models since many of the parts are interchangeable. It should also be noted that these numbers were for ads in the U.S. and Canada only. The 350 twins were sold all over the world. Due to age and displacement restrictions in the U.K during the 1970s, the same models can be found as CB250/CL250/SL250. With the exception of pistons, rings, and cylinders, these 250s have completely interchangeable parts with the 350s.
The 350 Honda twins represent the most cost-effective of any form of motorcycle racing with organizations like WERA that run staggered races of modern and vintage bike races at GP style tracks all over the country. Other organizations that race motorcycles make it a point to allow some form of the 350 Honda eligible in classes they run.
Racing a 350 is usually done in one of two modes:
1) Stocker Class: In the stock form, the 350s are usually restricted to no more than 1.0 mm overbore from the stock displacement of 325cc (350 is a model number, not actual displacement) which will yield 335cc displacement. Stock CV carburetors, any ignition and drum brake system and any period (1970s) technology suspension and modern race compound tires are allowed. Limitations on the rim width and style are based on era correct recreations.
2) 350 on steroids: The 350 Honda were raced as modern production racers while new models were still available at local dealers. Boring the cylinders out to 362cc, adding high lift, variable timing cams, titanium valves, dual port-dual spark plugs modified heads, Mikuni VM carburetors, polished and ported heads are among just a few of the unrestricted (within the 362cc limit) that would help create more than 50 horse power from the originally designed 28 HP motor. Companies like Todd Henning Racing and Bore Tech offer parts and services for these type of race bike and always will.
Todd Henning Racing
Bore Tech Inc.
To find out more about 350 Honda vintage racing, here is a link to just one of the many race blogs available:
A supplement to the blog above is a document compiled about 350 Hondas and how to revive them after decades of dormancy.
With the sheer numbers of 350s out there at half a million, even if up to 1,000 bikes being parted out per year, it would take 5,000 years to deplete the supply. With the re-buildable characteristics and unprecedented support for the bike, the parting out would give way to recycling of parts. The continued value of the bikes would decrease the number being torn apart as well. As the ignition technology of a stock 350 is based on points and condensers, it is quite possible that the last vehicle ever to consume gasoline might just be a CL350, SL350, or CB350, especially considering the possibility of EMPs ending the world as we know it…