Monday, January 21, 2019

Honda 250-305s… The Rules


Honda churned out somewhere around 250,000 of the 1960-67 250-305cc twins. 60+ years later, they still turn up from the back of someone’s garage or at a swap meets, etc.; and people have questions! Because of the depth of changes within each of the three models: Dream, Scrambler and Super Hawk, I can only skim the top of the subject,  but hopefully this story will help to defuse some of the confusion about these classic machines.

Rule #1
They are NOT all the same. There are “early” and “late” Dreams, Scramblers and Super Hawks with changes that are external and internal. Always use the serial numbers for reference when seeking parts or just asking for help. For the most part, the overall engine and tuning specifications are quite similar within each model, but there are deviations that can be important if you are going in deep on a repair or restoration.

Rule #2
Like cars of the era, these are battery-powered motorcycles. While the permanent magnet charging systems can generate sufficient spark to get an engine started, they really need a fully-charged battery and functioning charging system to operate normally. If you jump start any of these bikes and then let the charging system wrestle with a dead/dying battery the charging system will pump out as much as 40volts AC into the 12v electrical system blowing up all the light bulbs and often damaging the rectifiers. 

Because of changes in the 12N9-3A batteries used in CB72-77 and later model CA77 Dreams, you MUST look for the ones with the extended posts, not the ones with small vertical posts. There are TWO different batteries used on the Dreams. They DO NOT interchange and the correct one must be used to match up with the different battery box, tool tray, battery ground and side cover options for each type.

Rule #3
Because of poor storage or neglect, the engines are often found to be seized solidly. Moisture build up inside the cylinders will cause water to corrode the cylinder walls and piston rings into the ring lands. Depending upon just how badly seized it is, using a penetrating oil to help unstick the pistons can be successful in allowing rotation of the crankshaft again. Some people have been successful in getting these engines running again, but usually the cylinder bores are damaged, causing further damage to the pistons/rings.

Invariably the piston rings are stuck in the piston ring lands and are unable to do their normal function of sealing up against the cylinder walls. Because the piston clearances are so small  (often just one or two thousandths of an inch), the engines appear to have compression and will run. The corrosion is generally so severe that even running the engines for hours will not release the rings from the pistons for normal operation. Eventually, the lack of piston ring control and damage to the cylinder walls causes blowby and exhaust smoke. 

Excess oil in the cylinders will foul the spark plugs and eventually use up the 1.5liters of oil that the engines depend upon for normal operation. Plan on re-boring the cylinders and replacing the pistons and rings, at the very least. OEM pistons are increasingly hard to find and when you do the prices are beyond silly ($200 each). CB and CA pistons can be swapped into other engines, with only a slight change in compression readings.  Early Dream pistons had thick 2mm rings, but eventually were superseded by a version using thinner 1.5mm CB rings. https://classichondarestoration.com has forged piston kits available as replacements for the cast OEM pistons.

Rule #4
Clean the centrifugal oil filter! Depending on the year of production, cleaning the filter may or may not require removal of the whole clutch cover. Later “big hole” clutch covers facilitate filter removal and replacement without cover removal, but it is a bit tricky to accomplish. The spinning oil filter is driven by a small crankshaft sprocket-driven chain. There is a thrust washer on the shaft that must be placed on the outside of the filter to prevent the locating pin from gouging the outer cover.  There is a small o-ring that seals the cover to the filter body. Replace the o-ring if damaged. They can often be reused if installed correctly. The filter body must be thoroughly cleaned, along with the inside of the cover. Any leftover scraps will go directly into the crankshaft bearings, so be diligent in your cleaning efforts.

In proper working order, these engines use very little oil, but some will be burned in normal operation. Make sure that the crankcases are filled to the top mark on the dipstick before riding out for any distance. These engines do not have valve stem seals; however a clever air bleed system on the intake valve guides helps to lessen the oil consumption past the valve stems.  Honda’s GN4 10-30 oil is more than sufficient for normal operating conditions. 

When these engines were originally built, oil technology was in its infancy in many respects. Honda specified non-detergent oils originally, counting on regular oil changes to keep the engine clean inside. The problem with non-detergent oils is that they don’t help suspend particles in the oil like today’s detergent oils do successfully. 

It isn’t a bad idea to pull down the oil pump to check the screen for damage and for the presence of thick, mucky oil deposits and contaminants. Virtually every engine I have torn down has had a thick layer of deposits lying in the bottom of the engine cases. Even with detergent oils, when these engines sit for years unused, the suspended contaminants eventually fall out of suspension and wind up in the bottom of the engine.

Rule #5
ALWAYS ensure that the engine spark timing/advance is set properly. Check the timing with the engine running, using a dynamic timing light. Static spark timing is fine to get the engine running, but you must check it with the timing light when the engine is running to prevent piston seizures and help smooth out idling speed problems and carburetion setting issues. The spark advancer system is built into the camsprocket inside the engine.

Many things can and do go wrong with this design. Wear can develop between the spark advancer shaft and the camshaft that it rides in, causing sideplay in the points cam. The return springs can weaken or break, causing lazy spark advance return. The camsprocket is riveted together and eventually the rivets loosen up, allowing the camchain sprocket to loosen and walk back and forth within the mechanism. There is also some slop between the end of the points cam shaft and the plate that it engages in, within the camsprocket assembly causing some initial spark advance on start up. Honda Dream camsprockets have heavier weights and lighter return springs to speed up the spark timing on those models.  Camsprockets used on CB/CL models have lighter, smaller weights and stiffer return springs compared to those of the Dream models.

Rule #6
There are some “universal” engine parts that are shared within all three engine types. The kickstarter shafts, shift drums (except rotary gearbox types), primary chain tensioners, shift forks and shift selector shafts are usually the same in all models. 1960-62 shift shafts were shorter than later versions, however. Dreams have a completely different set of transmission ratios than the shared CB/CL gearboxes. There are 4 different clutch assembly setups, depending upon the application. The camchains, camchain guide rollers and camchain tensioners are all interchangeable, however the camchain tensioners have two different bolt patterns, changing in 1966.

Rule #7
There are “round bowl” and “square bowl” carburetor types, but they will interchange on various models. The round bowl versions came first, replaced by square bowl designs around 1964 for most models.  You can interchange the CB and CL77 carburetors if you swap out the jetting components.
Carbs come in 22mm and 26mm sizes for 250 and 305cc models, respectively. The 22mm carburetors for the 250s (and 305 Dreams) are all different in function and mounting points. Only the CB72 Super Hawks have the “power jet” carburetor functions. The CL72 Scrambler carburetors look identical, externally, however the power jet functions were deleted.  

Dream carburetors for 250-305s are interchangeable with minor jetting adjustments. Good carb parts source, as well as other 250-305 repair parts is www.4into1.com  or https://classichondarestoration.com The most common problem with carburetors is that the mounting flanges become warped, causing air leaks. Second most common problem is that the slide bores become distorted, causing the slides to stick when the engines heat up. With careful work, both conditions can be overcome.

Rule #8
Crankshafts all differ between the three models, as well as having a different balance factor between the 250 and 305s. The biggest challenge in rebuilding these engines is that the wrist pin holes in the un-bushed small rod ends get out of round, causing a part-throttle “chatter” sound. Honda made .004” oversized pins, however machining the pin bores to match is quite difficult with the crankshaft in its full assembly mode.  Competent machine shops can press the crankshafts apart, bore the rods to the oversize and/or re-bush the rods back to stock size again. Obviously, this will become an expensive repair step, if needed. The majority of the engines I have taken apart have had loose pin fits after 10k miles. If the engines have ever had a running piston seizure, the chances of rod damage are quite high.

Rule #9
The electric starter versions of these engines (CA/CB72-77) have a total of 5 chains in place to operate the motorcycle. The original primary chains, which connect the crankshaft to the clutch outer, stretch easily and begin to strike the inside surfaces of the clutch cover when they are out of spec. OEM primary chains are pretty much extinct, however a chain/sprocket company in the UK has come up with an endless 3/8x3/8 chain which works perfectly in these engines. They can also supply the tiny oil filter drive chain, camchains and starter chains. In a pinch, camchains can be cut up and shortened for use in the electric starter models.  www.sprocketsunlimited.com

Rule #10
Rebuilding the petcocks on the CB and CL models is fairly straight forward and plenty of repair kits are available.  Reserve tubes can crack or become broken off after 50 years of use. Overflow tubes can be replaced with 5mm brass tubing from a hobby shop. Dream petcocks are a whole different animal. They share a lot of internal parts with the 125-150 Benly models, however the outlet fittings are on opposite sized from each other, so the bodies are not interchangeable. Most aftermarket repair kits are not properly made, so cause installation and sealing problems.  Most of the internal sealing parts are still available from Honda warehouses and are highly recommended. A few parts are NLA in the US, but can be sourced from eBay sellers in Thailand and other Asian countries. Look out for warped petcock bodies that no longer seal properly against the bottom of the fuel tanks.


Obviously, there are many areas of these bikes that require careful study so that any parts purchases are not wasted due to a lack of knowledge about the kinds of changes that have occurred over the years. I offer comprehensive digital download packages of restoration reference files that are targeted for each of the 3 models.  See my site: www.vintagehonda.com for details and to order. I always welcome questions and can often guide people in the right direction for parts purchases and other restoration resources around the world.
                                                                       Bill Silver aka MrHonda

Tuesday, January 15, 2019

Eighth-liter wonders… the Honda 125... singles, twins, fours and fives!


Street bike models
As Honda’s new Benly J-series machines evolved, from 1953-58, the engine displacement began at 89cc and eventually rose to a full 125cc, with the introduction of the 1955 JB Benly model, which took advantage of a new law allowing for this larger-sized engine in Japan. There were severe restrictions on manufacturers in the 1950s, which eventually loosened up, as the decade passed.

The Benly J-series 125cc engines doubled in horsepower from 4.5 to 9.5 between the 1955 and 1958 editions, as these simple pushrod-powered bikes fought to compete and overcome challenges from the hundreds of other Japanese motorcycle manufacturers in post-war Japan. When the limit was reached for the single-cylinder models, the “new” 125cc Benly models became OHC, short-stroke, twins with 44x41 engine dimensions. Similar to the new 250-305cc Dream twins, the first-year 1958 models, named C90, came without electric starter motor options.  By 1959, Honda expanded the line-up, adding the new electric-start model C92, along with a highly-engineered “Sport” version called the CB92 Benly Super Sport. And with a twist of the boring bar, new 154cc models, based upon the 125cc engine design were announced as C95 and even a CB95 for that one year.

All Benly twins rode on leading-link suspension up front and a simple pressed-steel swing arm in the back, located by a pair of non-adjustable telescopic shock absorbers.  The standard Benly 125-150 models looked like little 7/8ths scale versions of the larger 250-305 Dreams, which came to market in late 1957, thus they have become known as “Baby Dreams” by some owners.

These sturdy little OHC twins featured a single carburetor which split the mixture into each cylinder alternately, due to the 360 degree crankshaft configuration. Ignition was a simple single set of contact points operated from the end of the crankshaft for accurate ignition timing. A single 6v dual-tower ignition coil was bolted up inside the backbone frame with its twin spark plug wire leads dangling downwards connecting to small 10mm spark plugs for the first few years. Eventually, the spark plug size was increased to 12mm and numerous changes to crankshafts and other engine internals yielded a fast and reliable small-bore street machine. The C92 models were rated at 11.5hp at 9,500rpms, while the CB92 Super Sports model carried a 15hp rating at 10,500 rpms; power unheard of in those days. Honda made specific tank badges for most of their models, until 1968. The little Benly models used “Benly” only badges for 1959-61, then switched to “Benly 125” badges for the remaining years of production, including the use on the CR93 street bikes.

American Honda did import a 1959 CA92 125cc model for just that one year, followed by the larger-bore 154cc CA95s (named the Honda 150Touring), which sold from 1960-65. The US did not impose cc restrictions on small bikes and riders, unlike Japan, so it was “the bigger the better” for the US market enthusiasts. Honda responded rapidly to the unfolding new bike market, offering the 305cc options for the larger models, over the almost identical 250cc versions.

Other than the CB92 Super Sport models, of which only about 1,000 came to the US, there were no other 125cc offerings in America until 1967, when the SS125A/CL125A models were introduced. Design-wise, the “new” 125cc twins were visual duplicates for the early Benly models, which shared the “side camchain” feature, but it became apparent that almost none of the early Benly parts were being shared with the new-generation machines.

There was a Honda CB125 (CB93) model, which was a 125cc version of the CB160 (CB96), but they were not officially imported into the US.  The mysterious Honda CBXX codes were finally dropped in 1968 for the most part, when the bikes were designated by their displacement size; i.e. CB350, CL175, CB450, etc.

In the US, only the pressed-steel framed models (with 17” wheels) were offered in that 1967-68 timeframe, whereas the domestic and European editions had twin-carb, 5-speed versions stuffed into tubular frames with full 18” wheel sets. Non-US models were marked as CB125K3 for the early models, which featured CB77-style 2:1 instrument gauges with tach and speedo in one single oval-shaped unit. These bikes featured an 11,500 rpm redline and all the full features of the larger CB/CL175 models, which were seen in the US.

Honda did use the single carburetor engine in the domestic CD125 models, again not seen in the US, but they were delivered in Canada at the same time as the SS/CL125A models were sold in America. In photos of European models, the same side-cam engine was used in various frame/chassis setups, with variations in the locations of the ignition systems and other details.

When Honda finally retired their aging 4-speed S90/CT90/SL90 horizontal singles in 1969, their replacement was first released in Japan as the CB90, a nearly-vertical OHC style single with a 5 speed transmission. By 1970, the engine was bored out to 100cc and released to the US markets in CB100 and CL100 versions. These continued until 1973 when Honda broke out the boring bar, once again, bring the displacement out to 122cc as the new CB125S0 edition. It was basically a bored out CB100 and continued to have the same drum-brake as the base 100cc models. When Honda rolled out the 1974 version of the CB125 (CB125S1), enthusiasts were surprised to see a full-featured model with a tachometer and a clever, mechanically-operated disc brake in the front wheel. Curb weight climbed only 10 lbs from the near-200lb weight of the S90/CL90 models of the 1960s, but the bikes top speeds barely improved at all. While many S90s seemed to be able to touch 70mph, the CB125S1 was a 65 mph machine, even with a tail-wind. Just about all of the 100-125cc editions had a single 22mm carburetor attached, with only minor jetting setting them apart.

(Side-bar story: Your author bought and tuned a 1974 CB125S1 for the 125cc production class racing in Southern California. At the end of the season he captured the 125cc class championship in both the CMC and AFM racing organizations. With help from Yoshimura-supplied engine parts, the bike regularly reached speeds of 80+mph and had the best brakes of the class.) 

The CB125S1 and 1975 CB125S2 models were identical apart from their paint schemes, still sharing the same one-piece cylinder head design inherited from the CB90/100 models. The minimalist cam bearing support of that cylinder head design lead to worn cam/head bearings, causing the camshafts to wobble around in the head during operation. With the point cam mounted at the end of the camshaft, ignition timing also suffered inaccuracies, especially at high rpms. Hard-core racers, who campaigned the SL125 variants in off-road racing, resorted to machining the camshaft and cylinder heads for needle bearing conversions to help secure the camshaft firmly in the cylinder head.

By 1976, the revised CB126 ’76 models gained 2ccs, a new 2-piece cylinder head, but lost their tachometers. The cylinder head was also redesigned with a split-port intake runner to help boost mid-range torque and engine efficiency and the carburetors were finally rubber-mounted to help reduce fuel frothing at high rpms. Continued use of small-bore carburetors and mild valve timing yielded reliable performance, but nothing truly noteworthy.

The 1977-78 editions were again just a color change upgrade. By 1979 the front disc brake disappeared, replaced by the generic drum brake package seen in the first editions. The 1979-80 models continued much the same as the earlier editions but with new mufflers and a styling package. Finally a CDI ignition package was installed for the 1981-84 models. The 1984 models were upgraded to 12v, after 14 years of suffering with tiny 6v electric power.
Honda did not offer any CB125S models in 1983, owing to a backlog of unsold models in their inventories. The 1984-85 editions were all made in Brazil, as Honda phased out the 125cc streetbike line-up for good.

Not sold in the US, but were offered to MSF course sites was the CB125T. This engine was a derivation of the US-spec CM185T and CM200T designs (forerunners of the Honda 250 Rebel). While the US “Cruiser” models had 360 degree crankshafts,  6v electrics, single carburetors and 4-speed gearboxes, the CB125Ts came out of the box with 180 degree crankshafts, 12 v electrics, dual carbs and a 5-speed transmission. The first-generation bikes came with regular, spoke wire wheels and the mechanical disc brake seen on the CB125S models.  The dry-weight figures were in the 250 lb range, but these bikes would pull upwards of 80mph at their 12k rpm redlines. While the early bikes never made it to the US, American Honda worked out some kind of a lend-lease program with the Motorcycle Safety Foundation organization and supplied some specially-equipped CB125TT models as “learner” bikes for the rider programs. The bikes were never supposed to be titled or registered in the US, due to lack of EPA approvals on that model.

The CB125T2 models had Comstar wheels, a front hydraulic brake and other amenities in keeping with the design themes of the 1980s and early 1990s. The bikes were widely distributed throughout Europe, Asia, Africa and Australia, where countries created rider/taxation restrictions on certain classes of riders.

Workhorse model CG125 Honda singles were mass-produced and featured a plain, pushrod engine configuration vs. the typical OHC models sold as a higher level model. Low-powered but reliable as a rock, these bikes suffered at the hands of non-mechanics worldwide, where they were treated more as a transportation appliance than as a spirited means of riding joys. Just another example of Honda targeting a specific market with their very “Benly” product line. Convenience over all other considerations, with reliability as a must. Millions would agree that the target was met successfully.

Roadracer 125s
Primarily offered as a high-performance street machine, Honda did offer CB92R models, kitted for 125cc class road racing in the US. Starting with the base CB92 machine, a long list of “YB” race kit options was available as a turn-key racer or the individual parts could be ordered separately. YB parts included: pistons/rings, camshaft, valve springs, racing ignition coil, two lengths of racing megaphones, alloy rims, tachometer option, racing seat, footpegs, starter delete and stator/rotor delete options and even pre-drilled fasteners. CB92Rs were capable of nearly 85 mph at 11.500rpms.

In 1962-3 Honda offered the CR93 production roadracer and a handful of "street bike" versions. Few of these made it to the US, but they were popular racing machines in Japan and the UK. These bikes were DOHC, 4 valve powered with gear-driven camshaft drives, capable of approaching 100 mph.

Honda made huge headways with their 125s, eventually on the world GP stage, however their first efforts in 1959 were a bit under the competition’s levels of achievement. The RC141 was a 44x41mm twin with 2 valves per cylinder, featuring a bevel-drive system to drive the camshafts.  It was quickly replaced by the 4 valve per cylinder RC142 at the IOM races. Honda actually used CB92 bikes as trainers for the fresh-from-Japan riders who had never seen the IOM course before.  It was said that the bike actually arrived with knobby tires fitted, as used on the Mr. Asama race course, which is made of volcanic cinders. Honda quickly fitted proper roadracing tires on their bikes for the rest of the events, but the first bikes all had leading-link suspensions at the front end, which lead to rather poor lap times. Honda did achieve a team prize for their 6-7-8 finishes in their first attempt at the IOM course, however.

Honda returned in 1960-61 with RC163 and 2RC-163 models, still DOHC 4 valve twins with 6-speed transmissions. By 1963 Honda served up a 125cc four cylinder model RC146, followed by 1964 2RC-146 and 4RC-146 models with 7-speed transmissions. In 1965-66 Honda dropped the big 5-cylinder, 8-speed bomb upon the 125cc class and won championships easily. These engines revved to 22,000 rpms and were capable of over 125 mph.

Honda left the world motorcycle racing stage in 1967, as they concentrated upon F-1 racing and the manufacture of automobiles and other automotive equipment. The next “factory” racer models to become available to a select few in the US were the CR125 Elsinore-based MT125R racers. The first generations had the same mechanical front disc brake and used a fairly stock CR125M engine with a special close-ratio gearbox. Feather-light, they could eclipse 110-mph if you could keep them on the boil. Later MT125R2 models were equipped with a water-cooled top end and hydraulic disc brake on the front wheel. These bikes were raced extensively in the late 1970s and into the 1980s. Eventually, as Honda re-entered the world of roadracing with their new NSR250 and NSR500, the 125cc class became the place to learn your roadracing craft, so Honda tooled up roadrace -specific RS125/NSR125 machines for world-wide distribution.

Dual-Sport/Off-road models
Honda offered a different set of “YB” racing parts for the CB92s, which created a “Scrambler” version of the 1960-62 streetbike. Dave Ekins, famous off-road racer in the 1950-60s, successfully raced a CB95 version of the bike in off-road competition; however it was eventually disqualified because it wasn’t a model that was officially sold in the US. That was Honda’s only 125cc-sized racer in the 1960s.

Honda broke new ground with 2-stroke CR125M Elsinore MX racers and the MT125 Elsinore street version, starting in 1974. This was Honda’s first departure from the reliable, but heavy and underpowered, four- stroke singles, which could never make the same kind of horsepower that a two-stroke single of the same size can generate.

Honda offered Dual-Sport and Trials 125cc versions of these early singles in TL125, CL125, SL125 and XL125 models.  Ironically, the SL125s were offered as early as 1971, while the street models didn’t arrive until two years later. The early XL125 models were pepped-up with higher compression pistons, upgraded camshaft, larger valves and a 24mm carburetor. The 1979-1985 XL125S models featured a slick 6-speed transmission. The TL125s, offered for just 3 years, spanned the transition of one-piece to two-piece cylinder heads, as did the other versions. TL125s were specifically designed to go SLOW, so they were detuned and setup for slow speed riding and low-end torque for Trials events.

By 1985, the four-stroke 125cc Honda singles had died out, in all of their variations. There was a NX125 offered from 1989-92, but these little dual-sport machines sold poorly, at least in the US.

You can’t buy them here, in the US, but the 21st Century has brought bikes like the CBR125R, water-cooled, SOHC, 2-valve, four stroke single in a cool sport bike chassis, with fuel injection! So, I guess after 58 years the concept of the “Honda 125” will never die after all.
These are just the highlights of the 125cc Honda series. I know there are many, many other 125cc models, sold in specific countries/markets which I have never seen or heard of before. In countries where 50cc bikes rule, a 125cc model is a “big bike” to those enthusiasts. Long live the Honda 125!
Bill “MrHonda” Silver

The Honda Dream battery nightmare…


Benly vs. Dream battery confusion

Although you will find parts ads and other listings for Honda “Dreams,” which wind up describing CA95 Benly or CA160 Touring 160 models (sometimes called Baby Dreams), the only true 1960s Honda “Dreams” are the 250-305cc models.  Only a few parts will actually interchange between the two series (Dream vs. Benly), such as the ignition switches and the rear shock covers. I usually refer to Benly/CA160 models as a “7/8 scale Dream.” Despite similarities on the chassis design, headlight shape, suspension function and 16” wheel sizes, Honda made the 150-160 models completely different all over.

Another parts issue that arises for new owner’s is their bikes often need new batteries, so they search for “Honda Dream” battery, instead of the correct “Honda Benly” (or CA95 CA160) battery. The Benly series machines are ALL SIX volt electrical systems, so a “Dream” battery won’t fit in the battery tray, in any way, shape or form and if it did, it would immediately fry all the electrical components in a Benly series bike.  A secondary cause for confusion was that the CA160 models (no longer called Benlys, although they were essentially a 150cc Benly with a 160 engine installed) continued to use the SIX volt electrics, even though the CB160 and CL160s had adopted TWELVE volt systems. This is just one part of the battery dilemma for vintage Honda Benly-Dream owners.

Early vs. Late Dream Battery issues

In a perfect world, Honda 250-305 Dreams would all have the same TWELVE volt battery, but of course they do not.  When the first dry-sump 250-305cc Dreams were released in 1957-60 timeframe, they had large SIX volt batteries installed, in order to crank over the engine efficiently. When the new wet-sump Dreams were released in late 1960, the revised machine was equipped with a full TWELVE volt electrical system. Honda cranked out thousands of early 250-305cc Dreams from 1960-65/66 with the same battery, which was somewhat taller and thinner than many other batteries on the market.

In the meantime, Honda was using the 12N9-3A battery in all of their CB72-77 Hawk/Super Hawk machines with great effect. Apparently Honda decided to use the same battery in both CA and CB models, so they re-engineered the frame, battery box, tool tray, battery ground strap, battery cover and knob to accommodate the change. This changeover occurred at CA-72 1000330 (early 1965 production) and at CA77-1010863 (late 1965 or early 1966). The 12N9-3A battery is 5.3” x 3” x 5.5” (LWH).

Invariably, new Dream owners go online, see Honda Dream Battery listings and assume that one battery fits all models, including theirs. So, you can imagine the surprised buyer when the battery that they receive is nothing close to what they needed, if their bike is the “early” style battery type.  The few remaining early type batteries are sold as WISCO JB-2 editions. There was a GS branded battery offered under a slightly different number, but Honda has long discontinued the early style YUASA MB J4-12 OEM batteries due to their rather sparse sales numbers and singular applications.  The early batteries are 7 3/8" x 2 9/16" x 5 1/2" (LWH) YUASA batteries are a highly known and respected manufacturer of motorcycle batteries, but I have often found that there are ordering errors, even on their own website. The last time I checked their site, the 12N9-3A batteries were no longer listed. 

The first generation of those “new style” batteries had horizontal terminal posts, but in recent years, the posts were changed to an upright design, but no change was made to the part number. There are inexpensive aftermarket batteries being made now in Taiwan and elsewhere in SE Asia, with tiny 5mm attachment bolts instead of the previously supplied 6mm hardware. So, double check the specifications of the hardware to avoid disappointments.  Current EBay listings for Honda Dream batteries show various types, some showing 1963-66 applications, which makes no sense whatsoever. There are new maintenance free batteries and even lithium ion batteries coming to market now, but nothing new that actually fits the early Dream model frames and hardware properly.
So, why is that important?
Good Question!
The answer is that the battery holds an air filter body cover in place, on the side of the frame. The cover has no attachments or hardware to secure it where it belongs.  Only the correct-sized battery will hold the cover in the frame recess and be properly secured in place by the tool tray.  You cannot mix-match batteries, tool trays, battery ground straps, battery covers/latch knobs and their respective frames.

Check the illustrations accompanying this report to see some of the details surrounding this long-standing issue for Honda Dream owners.



"Early Dream" 12v battery

Correct 12N9-3A battery for "Late Dreams" and CB72-77 Hawks



Bill “MrHonda” Silver

The mystery of the 1963 “5K” CA77 Dreams


I was recently contacted by a SoCal gentleman who was complaining about some oil leaks on his 1963 CA77 Dream. The serial numbers on this bike are CA78-311781 with engine number CA77E-316817. Whereas, virtually all 250-305cc Honda twins have serial numbers which are within 200 digits from each other, this one has numbers with a five thousand+ number spread.  If you deduct the five thousand number difference, the engine/frame serial numbers are only 36 numbers apart. 

Below are some examples of strike-through numbers, apparently done at the factory, but could have been done at a dealership. The mystery will never be solved, I'm afraid.





I recall hearing from a few CA77 owners who were wondering if their bikes had the original engines in them, because their serial numbers were a little over five thousand numbers apart. I just figured that the bikes had experienced an engine swap somewhere along the line and that was that.
However, over the past few months, a VJMC member and Dream enthusiast, named Bill Soli, began inquiring about the fact that more than a few bikes from the 1963 model ranges were showing up with a five thousand difference in their numbers.  He had been polling forum members from various sources and collecting numerous examples of this five thousand number spread effect. Obviously, this was not just a random case of engine swapping now. Something significant was going on, which was not reported within the Honda serial number listings, released to date.

American Honda’s parts books listings left a big gap in the timeframe from when the original 1960-62 bikes were changed over to the restyled “CA78” versions, These were only mentioned as beginning production in 1964. Apparently, 1963 models didn’t seem to exist, according to the AHMC records. Honda’s parts books show 901 versions of the CA77 models being built in the 1962 year of production, then just skip to the six digit serial numbers of 1964.
Here’s an abbreviated look at Honda’s serial number sequences for 1963, transposed from their parts books of 1968:
’63 Type                Engine                                                    Frame
C72        C72E-310001-323269                       C72-310001-323269
CII72     C72E-310001-349404                       C72-340001-352302
CA72     CA72E-310001-311910                    CA72-310001-311910
C77        C77E-310001-310896                       C77-310001-310896
CA77     CA77E-310001-314731                    CA77-310001-314731

There is nothing remarkable shown here, which is what I have used as a reference for a number of years.

The next entries are for 1964:
‘64 Type (1)
CIII72   C72E-100001-110852                       C72-100001-110852
CIIIA72 CA72E-100001-100760                   CA72-100001-100760
C78        C77E-100001-101512                       C78-100001-101512
CA78     CA77E-100001-108176                    CA78-100001-108176
‘64 Type (2)
CIII72   C72E-400001-405219                       C72-400001-405030
CIIIA72 CA72-400001-401542                      CA72-400001-401520
C78        C77E-400001-400978                       C78-400001-400975
CA78     CA77E-400001-403456                    CA78-400001-403456

You can see that Honda went a little schizoid with their numbering system. First, they used a series of 6 digit serial numbers that began with a ONE for awhile, they then changed their minds and began using serial numbers beginning with a FOUR, which is more in line with the previous years.

Secondly, they switched from calling out their chassis numbers from C/CA77 to C/CA78. This corresponds to the changeover from the early seamless fuel tanks to the reshaped seamed tanks, which also relocated the fuel crossover hoses from the front of the fuel tank to the middle section. The chromed fuel tank side covers were reshaped, along with the rubber knee pads. This also ushered in the changed fuel tank’s plastic emblems script from “Honda Dream 250 or Dream 300” to just plain “Honda 250” or “Honda 300” styles.

There are other changes in the C/CA78 series, regarding the handlebars and controls. The clamp-on mirrors, sourced from the CE71, were replaced with CB72 lever brackets, which incorporated mirror mounts on a raised pad. The hidden throttle cable system, sometimes called “Slide throttle” was also introduced. On the “delete” list was the formerly included tire pump, with mounting brackets and lock.

What really occurred, shown in some entries within the large “World version” of the parts books, is that the changeover from C/CA77 to C/CA78 happened during the 1963 model year, instead. Adding to the confusion is that the 252-305cc Dream was ALWAYS called a C/CA72-77 Dream and the 305 engines were ALWAYS stamped with C/CA77 all the way through their entire production life. If you see an engine with the numbers stamped C/CA78E, it is a fake.

Apparently, the only way that Honda could differentiate the engines destined for C/CA78s was to add five thousand numbers to the serial numbers. Why five thousand numbers? Who knows and we may never find out, anyway.

Suffice to say, now, that owner’s of 1963-series Honda Dream motorcycles who find themselves faced with this five thousand number spread between engine and frame numbers can now relax and be assured that their bikes came from the factory, serialized in this way.

Please note that I have been using C/CA77 or C/CA78 notations to cover both U.S (CA72-77) and domestic/Euro versions, which were identified as C77 or C78 models. U.S. models came with turn signals deleted, plus dual seats included; whereas many domestic C-77/78 models might have had sheet-metal handlebars, winkers (turn signals), solo seats w/luggage racks and even rotary shift gearboxes.
The whole CA77/CA78 engine/frame number system causes great confusion among new owners and all I can tell them is that “it is what it is.” Honda had their own way of doing things, logical or not, but not to fret when the frame numbers don’t seem to “match” the engine numbers.  All you have to remember is that ALL 250-305cc Dreams had CA77 engines, no matter what the frame numbers indicate.
Hopefully, I have cleared up some confusion about the serial number system for the 1963 editions.  Next time, we can discuss why Honda put a SEVEN in the serial numbers, right after the first digit, instead of a zero.  Isn’t this fun?      Bill “MrHonda” Silver

Wednesday, January 2, 2019

Early or Late? How do you tell the difference between vintage Hondas?


The terms “early” and “late” are somewhat subjective and somewhat objective, depending on how you are applying the definition as it applies to vintage Honda motorcycles. Since American Honda setup shop in 1958, just about everything sold before 1960-61 would be considered “really early,” by most aficionados of the marque. Other than the first generation Honda Cubs, the CB92 and CA95 Benlys, the “big bikes” (250-305cc) were dry-sump Dreams and few of those were sold in the beginning.

Once Honda’s production machinery really ramped up in the early 1960s, bikes came pouring off the lines in as little as every 15 seconds! That figure applies to Honda step-thru Cub models, however. Those early pushrod bikes were run continuously until about 1965, when the OHC engine designs took over. Some versions of the Honda Cub 50s (and some 90cc models) have been in continuous production since 1959, with over 65 million units produced, world-wide.

Other “early” small-bore machines were the OHV Honda 90 street and trail bikes, known as the C200 and the CT200. Again, these were superseded by OHC engines in the 1965 era.

Looking at the small twins, the 150cc Benly Touring 150s, which were also released in 1959, had a styling makeover in 1963, where the fuel tank, panels, rubbers, handlebars and mufflers were all redesigned.

Similarly, the “early” 250-305cc Dreams had their own rework sessions in late 1963, where the model changed from C(CA)77 to C(CA)78, which brought changes to the fuel tank, side panels, rubbers, tank badges and handlebar hardware. So, the true CA77 models can be considered “early” while the CA78s  are recognized as “late” versions.  While these styling changes are readily apparent, that was not the end of the design process. Honda reconfigured the frame, tool tray, battery ground, battery and side covers (and knobs) in 1966, changing the battery size/shape from the early, tall, thin battery to the wider, shorter 12N9-3A unit, also used in the CB77s.

Most collectors think the 1961-64 CB77s, equipped with flat handlebars, steel forks, flat seats and reverse-needle speedometer/tachometers were considered to be the classic “early versions.” In 1965, the flat handlebars gave way to low-rise units and the speedo-tach meter set mirrored the concentric CB450 Black Bomber instruments. 1966 brought alloy forks, requiring a new front fender stay design, plus the upswept seat shape, all of which carried through to the end of production.  Those features are commonly referred to as “late CB77” editions.

For many Scrambler owners, the 1962-65 CL72 250cc Scramblers had the look and the sounds associated with “early” models, which included slender alloy fenders, straight exhaust pipes with no muffler can on the back and the mostly ineffective “small brake” wheels/hubs.  In 1965, the CL77 was released, initially as a big bore motor transplant for the CL72. The fenders were changed to steel and they gradually widened to better encompass the rear wheel debris throw-off and to help keep them from cracking. The 1965 CL72 and CL77s had a “slip-on” muffler, which wrapped around the ends of the twin exhaust pipes, to better reduce the high-pitched, high-decibel exhaust notes. Those were quickly removed by the owners, forcing Honda to weld mufflers onto the later generation of exhaust systems.

By 1966, the CL77s were completely re-engineered with new alloy forks, double-leading shoe brakes, rubber mounted rear fender, seat, exhaust, footpegs, fork ears and a thicker chain guard. The net effect was a more beefy profile, carrying more weight and losing the slim, sleek look of the original concept. However, these “later” bikes were far more reliable and had the much-needed braking power lacking in the “early” models.

In 1965, Honda’s engineers refined the 250-305 engines, lowering the compression, changing the fin shape pattern of the cylinder heads, adding “square bowl” carburetors and other details that held them apart from the “early” editions.

1966 brought wholesale changes to the suspension systems on many models. The “early” S90, CB160, CB77 and CL77 caught up to the CB450K0 Black Bombers by having all of their fork lowers changed from the frame-color steel style to silver-painted alloy forks. The fork style helps delineate the “early” and “late” division line on all of those models.

In some cases, either the year or the country specification made a distinction between “early” and “late” type of handlebars. In some cases, early model Honda Sport Cubs, Super 90s and CB160s had “low bar” handlebar configurations. As production and sales increased in the US, a determination was made that the US bikes should have “Western” handlebars (read higher and wider) than the domestic and European counterparts.  So, the cool little “W” shaped handlebars for the C110 Sport Cubs and Super 90s gave way to unattractive and out of proportion “Western” handlebar configurations, requiring whole new cable sets for each model. Many of the bikes with “A” (for America) designators, like CA110, CA77 and US-specification CB160s and CB77s all had “Western bar” handlebar/cable combinations. 
However, if the bikes came into the US before 1964, they often had the lower handlebar sets, found on non-US models. If you are restoring a 1960s model bike, exactly to as-sold specifications, then you will have to study your parts books carefully to establish which handlebars and cables are needed to make the bike correct for that year edition.

Up to 1968, turn signals were not specified for the US market. The Honda S90 and CL90s and the CB/CL450s were a few of the carry-over machines, which came to the US without turn signals in the beginning and then had them added towards the end of production, which carried on past the 1968 cut-off date. Obviously, the turn signal/no turn signal machines are the dividing line between “early” and “late” models in Honda’s lineup for those affected by the change.

Another aspect of “late/early” models are how the bikes were affected by the change from JIS thread pitch to ISO pitches, starting with the 1968 production models.  The 250-305s and 160s were out of production by the end of 1967, so are not necessarily affected. You will find some models, like the “early” CL175K0 Scramblers, which are built with two sets of fasteners, as production progressed into the 1968-beyond models.