Skip to main content

See also:

Where have you been hiding, little Honda? A 900-mile CL360 revival story

Amazing original bike, down to the tires.
Amazing original bike, down to the tires.Bill Silver

A Honda is a Honda is a Honda, but I have not spent a lot of time wrenching on the CB/CL/CJ360 twins, in my 50+ years of bike experience. I think I owned one briefly in the early 1980s, but that was just a quick fix and flip bike. Recently, my young friend, Haley, whose CB360T was ailing for various reasons, got a couple of hours of my attention, which seems to have proven successful. However, as you kind readers have observed, my usual focus is on the 250-305 flavored Hondas.

A referral, lead the owner of a 900 mile original CL360 to seek me out for advice, which then lead to it showing up on my doorstep over the weekend. The bike had been through a few different owners, suffered a minor spill, but it mostly looked pretty darn original and unmolested. The replacement battery had very few volts left in it, but may come back to life after an overnight battery charge session. The air filters and covers were in a separate box, which also contained the remains of the original petcock and a handful of misc carburetor bits.

According to the current owner, Hugh, there were previous attempts at getting the bike up and going again, apparently with the use of a Keyster carb kit set. The timeline is a little fuzzy, so you just never know what you will find until you crack the float bowls open and have a look. We offloaded the bike, gave it a good look-over and Hugh jumped back into his borrowed truck for the trek back to Orange County. I immediately pulled the battery and put it on the charger and then set about removing the carburetor rack a few hours later.

DAY ONE

My long-standing issues with any of the 160-450cc Scrambler twins, is that you have to remove the exhaust systems to have access to the left hand air filters and carburetors. Reinstalling the exhaust systems by yourself can be a chore, with wrestling a weighty set of pipes and mufflers into the exhaust ports, keeping the exhaust flanges from sliding down the header pipes and connecting the rear muffler mounts to the frame with just two hands. I was happy to discover, at least at this stage with the air filters already removed, that the carburetors could be pulled through the rear of the frame, once the battery box was pulled out of position. I plopped the carb set on the work bench and studied the assembly for a few minutes. Two of the top diaphragm cover screws had been replaced with larger diameter ones, indicating that previous attempts at repairs apparently stripped out the original screws. Pulling those chromed covers off the tops allows the carb slides to be removed along with the attached rubber diaphragms. Both of the slides were stuck in the carb body bores due to old varnished gasoline, indicating that whoever had been in there before had done their work quite awhile ago. A little nudging on the carb slide, through the inlet opening dislodged the slides and out they came. Sadly, one side diaphragm had two tears at the base where it attaches to the carb slide. Finding serviceable OEM slide/diaphragms is increasingly difficult these days, but some companies have reproduced the rubber diaphragms and offer them for sale with directions on how to uncrimp/remove the old diaphragms and replace them with new ones, but it isn’t going to be alike a factory installation, in the end.

I was able to locate and purchase a good used part from an eBay seller, down in Arkansas, who promptly shipped it out the next day. My buddy, Marty Mattern, at 4:1.com offered up some K&L carb kits from his website, so it is looking like we’ll have all the necessary parts to get the bike up and running for less than $100. The rest of the carburetor teardown found a mix of old and new parts inside, including new idle jets and float valves. The carbs were varnished and scaly from old fuel residing inside the bowls for many years, but they were not beyond cleaning and a little scrubbing up, here and there.

I was able to remove everything except the needle jets from the carburetor bodies. I like to try to push them out with wooden chopsticks to prevent damage to the machined edges, but they wouldn’t budge. I used the chopsticks on the primary main jet nozzles and one wound up with bamboo lodged inside the discharge outlet, which will have to be eased out with tiny drills or my jet reamer set. It is important to get all of the emulsion tubes removed from the carburetor bodies on these carburetors because the cross-drilled holes often become plugged up. When this occurs, the fuel mixture cannot be emulsified properly (mixing fuel and air before being discharged through the outlet opening) and you wind up with performance issues because of the blobs of fuel being drawn into the air stream of the venturis.

The carb body and all the little bits were immersed in a small can of Berryman’s carb dip, which isn’t quite as powerful as it once was, but generally does a pretty good job of cleaning out varnish deposits. While waiting for carb components, my attention returned to the rest of the bike, where I can spend time adjusting the valves, checking compression, adjusting the camchain (and there is a TSB bulletin about replacing the camchain tensioner components) and cleaning the points in advance of an ignition timing check and any necessary adjustments.

My observations about the originality of the bike’s components left me wondering how the nearly bald rear tire and half-worn out rear brake shoes (based upon the position of the brake adjusting rod nut) could have suffered so much wear in just 900 miles. The tires were obviously the factory pair of Bridgestones, but the front, ribbed tire showed little wear in comparison to the ragged rear tire. Unlike the previous CL350-450s, which carried 19” front wheel/tire assemblies, the CL360 (made for only two years) had 18” hoops on both ends. The 300 x 18 front and 3.50 x 18 rear tire sizes were exactly the same as those on my 1981 CB250RS single, which weighed about 100 lbs less that this 360cc twin.

The 360cc series of bikes replaced the previous 350cc models, but in an entirely new design. Where the 350s carried the camshaft bearings on end caps, the 360 had a full-width cylinder head, not unlike a four cylinder model, still with plain bearings in the head cradling the camshaft support loads. The main design feature was the relocation of the tachometer gear drive from outboard to inboard the right side camshaft lobes. The 360s (except for the “café-version” CJ360) had new 6-speed transmissions installed to help spread the power across the range while allowing for a taller final gear step. These engines did not receive any counter-balancing engineering, so they shake a little more than their 350cc forbearers. The vibration issues were not resolved until Honda built brand new CB400T twins in 1978, which did feature a chain-driven counterbalance system to offset the 360 degree crankshafts installed in those new models.

Whereas all the previous twins had separate carburetors mounted to each intake port, the 360s had their carburetors ganged together on a mounting plate, which allows for more accurate synchronization and the use of the mandatory push-pull double carburetor cable setup. This safety feature necessitates more complexity in connecting the throttle plate shafts together. The link which connects the two shafts together is a hollow square tube, with holes drilled into the side and one end has a threaded hole for the end piece. There are four little ball sockets, a long spacer, a spring and lockwasher/nut, in addition to two small flat nylon washers and e-clips to help secure the whole assembly together.

There was some cause for alarm when an etched away part of the threaded boss where the idle mixture screw cap threads down into the body. It looks as if the end cap is threaded far enough to cover the threads below and seal off the jet from outside fueling, but the whole thing is marginal, at best. One of the carburetor floats, which have phenolic float ends, had a portion of the plastic material eaten away, which may well cause the float to absorb gasoline and start to sink.

There are five different calibrations for these carburetor sets; however the aftermarket carb kit makers only chose to make a generic one with just the #100 main jet and a #35 idle jet. The later model #754A carbs use a #110 main jet. Neither of the available repair kits include a primary main jet (normally #68), however the jet selections for the multiple calibrations of the Honda 350s is much worse as their calibrations range all over the place.

DAY TWO

Parts, ordered on Friday afternoon, from two different sources, arrived in Monday’s mail advancing my plans for getting the CL360 into operable condition. The used slide/diaphragm assembly arrived in a VERY large Priority Mail box, while the two carb kids came in an envelope. Methodical cleaning of the carburetor bodies and jets allowed nearly complete reassembly of the carburetor set, fully mounted on the base plate. After installing the slide/diaphragm into the right side carburetor, the rebuild task was complete for the moment. A few days of the float bowl o-rings sitting out in the hot sun allowed the alcohol to be released from the material and the bowl gasket reinstalled into the bowl groove with a dab of silicone grease placed in a few key locations. I attempted to seal up the surface of the float with some blue Lock-tite, which may just dissolve in the fuel when the bowls are refilled, but it was worth the experiment.

The carburetor rack fits easily into the frame and onto the inlet manifolds, once the battery box is out of the way. The throttle cables installed with relative ease, as well. I was relieved to discover that the left side air filter assembly does install into the frame without removal of the exhaust system! And the left side cover also slips into place without the need to wrestle the pipes out of the way. Honda finally got it right for the Scrambler twins!

With carbs and air filters all installed, the bike was nearing the fire-up stage. I had previously checked valve clearances and ignition timing, so this was about the last stage of the repair cycle. Installing the Brand –X battery, which had been cooking overnight on the charger and read 13v before it was hooked up, suddenly went to 7v when the starter button was pressed. BLAH! A quick call to the closest Honda dealer, over in Lemon Grove, CA yielded positive results for my battery request. They began to service the battery by the time I had hung up the phone. Rushing across town with the old battery in hand, I gladly exchanged it with a fresh power source and headed back for home. Ideally, a freshly-serviced battery needs about 3 hours of standing time; then it can go on a charger for another 5-6 hours at about a 1 amp rate. I was in a hurry, so chose to just kickstart the bike once the fresh battery was installed.

The fuel petcock had already been replaced with a new OEM unit, which showed little signs of serious contamination from old fuel or rust. There was some rust bits felt in the roof of the fuel tank, but nothing of great concern. The new petcock has a little screen over the RESERVE feed portion of the unit, so it will screen out any floaters for the most part. My primary job was to get the bike running reliably and within a preferred $500 budget. With a couple of gallons of fresh fuel inserted into the fuel tank and the fuel lines all hooked up, the choke was placed in ON position and a few sturdy kicks brought the bike to life, first stuttering and dying, then recovering to a fast idle once it was kicked a couple of more times.

The first few minutes of a bike’s awakening can be critical for components inside the engine which haven’t seen lubrication for 10-20 years. Keeping the idle speed around 2-3k rpms and listening intently for any signs of lubrication failure led to no concerns. The right side carburetor float valve seemed to be having some closing issues on and off, but once the bike was running the vibration and a little rocking back and forth seemed to allow the float valve needle to settle into place, as designed.

One quick lap around the block reminded me to bring it back for a tire pressure check, as the bike seemed to fall into left hand corners more easily than when turning right. Air pressures were sub-20 and the rear axle marks were off about 1/8” from side to side. The drive chain had been over-tightened, as well, so loosening the chain, aligning the axle and a little bit of chain lubrication put things right again, once the tire pressures were brought back to normal. A longer follow-up ride gave more confidence and joy to the experience. The bikes sound quite a bit like their 350cc brethren, but the extra 6th gear closes up gear spacing gaps and gives it a more relaxed cruising speed. I did detect some vibration phases around 4,500 rpms, though, which is to be expected for a non-counterbalanced engine. Throttle response was good, idling was nice and smooth with little in the way of engine noise at all.

The bike did seem to suffer from some clutch drag, as finding neutral was just as vexing as it was on the last CB350 twin I serviced a few weeks ago. The clutch wasn’t “stuck” once the engine fired up, but I suspect that it may have been at some point in time. My “solution” was to drive the bike about 30-40 mph and fan the clutch about a dozen times, allowing it to slip and hook-up repeatedly. It isn’t the kindest thing to do to an engine or clutch, but I surmised that it might knock off some of the rough material that usually attaches to the steel clutch plates when the clutch is compressed for years at a time. Stopping once to turn around, the neutral selection seemed to improve. I tried the same tactic again on the return drive up a long grade, at 50 mph, fanning the clutch a few more times.

Once home, the oil was changed, which remains a messy task on the 350-360-450 twins of that era. Honda used a 22mm drain plug which causes a flood when it is removed from the engine cases. After draining the used oil into a collection pan, I discovered that whoever changed the oil previously had failed to replace the sealing washer. The plug was not leaking, but I didn’t want to chance it without some kind of washer. A trip to the local O-Reilly’s auto parts store offered only two options: pay $14 for a “Dodge Truck” 22mm drain plug and rubber gasket or try out the GM carburetor inlet packing set for $2.99, which had some suitable, but narrow, fiber washers of the right diameter. I chose those and it seemed to work fine for this emergency application.

As I was sending an email report to the owner, I received one from him stating that he was shipping a 3.25x18 rear tire to me for replacement of the nearly bald OEM rear tire, so the party isn’t quite over just yet.

You don’t get many chances to experience a near-new vintage Honda in its original form. The bike runs fine and sounds as good as you would expect one to be at 900 miles, but it holds no special charm for me, as a potential owner in the future. It is destined to return to Costa Mesa in a few days, where it can charm the locals with its originality and uniqueness; as a low-mile, low-serial numbered, classic Honda CL360 Scrambler.

Bill “MrHonda” SilverWhere you been hiding, little Honda? A 900-mile CL360 revival

A Honda is a Honda is a Honda, but I have not spent a lot of time wrenching on the CB/CL/CJ360 twins, in my 50+ years of bike experience. I think I owned one briefly in the early 1980s, but that was just a quick fix and flip bike. Recently, my young friend, Haley, whose CB360T was ailing for various reasons got a couple of hours of my attention, which seems to have proven successful. However, as you kind readers have observed, my usual focus is on the 250-305 flavored Hondas.

A referral, lead the owner of a 900 mile original CL360 to seek me out for advice, which then lead to it showing up on my doorstep over the weekend. The bike had been through a few different owners, suffered a minor spill, but it mostly looked pretty darn original and unmolested. The replacement battery had very few volts left in it, but may come back to life after an overnight battery charge session. The air filters and covers were in a separate box, which also contained the remains of the original petcock and a handful of misc carburetor bits.

According to the current owner, Hugh, there were previous attempts at getting the bike up and going again, apparently with the use of a Keyster carb kit set. The timeline is a little fuzzy, so you just never know what you will find until you crack the float bowls open and have a look. We offloaded the bike, gave it a good look-over and Hugh jumped back into his borrowed truck for the trek back to Orange County. I immediately pulled the battery and put it on the charger and then set about removing the carburetor rack a few hours later.

DAY ONE

My long-standing issues with any of the 160-450cc Scrambler twins, is that you have to remove the exhaust systems to have access to the left hand air filters and carburetors. Reinstalling the exhaust systems by yourself can be a chore, with wrestling a weighty set of pipes and mufflers into the exhaust ports, keeping the exhaust flanges from sliding down the header pipes and connecting the rear muffler mounts to the frame with just two hands. I was happy to discover, at least at this stage with the air filters already removed, that the carburetors could be pulled through the rear of the frame, once the battery box was pulled out of position. I plopped the carb set on the work bench and studied the assembly for a few minutes. Two of the top diaphragm cover screws had been replaced with larger diameter ones, indicating that previous attempts at repairs apparently stripped out the original screws. Pulling those chromed covers off the tops allows the carb slides to be removed along with the attached rubber diaphragms. Both of the slides were stuck in the carb body bores due to old varnished gasoline, indicating that whoever had been in there before had done their work quite awhile ago. A little nudging on the carb slide, through the inlet opening dislodged the slides and out they came. Sadly, one side diaphragm had two tears at the base where it attaches to the carb slide. Finding serviceable OEM slide/diaphragms is increasingly difficult these days, but some companies have reproduced the rubber diaphragms and offer them for sale with directions on how to uncrimp/remove the old diaphragms and replace them with new ones, but it isn’t going to be alike a factory installation, in the end.

I was able to locate and purchase a good used part from an eBay seller, down in Arkansas, who promptly shipped it out the next day. My buddy, Marty Mattern, at 4:1.com offered up some K&L carb kits from his website, so it is looking like we’ll have all the necessary parts to get the bike up and running for less than $100. The rest of the carburetor teardown found a mix of old and new parts inside, including new idle jets and float valves. The carbs were varnished and scaly from old fuel residing inside the bowls for many years, but they were not beyond cleaning and a little scrubbing up, here and there.

I was able to remove everything except the needle jets from the carburetor bodies. I like to try to push them out with wooden chopsticks to prevent damage to the machined edges, but they wouldn’t budge. I used the chopsticks on the primary main jet nozzles and one wound up with bamboo lodged inside the discharge outlet, which will have to be eased out with tiny drills or my jet reamer set. It is important to get all of the emulsion tubes removed from the carburetor bodies on these carburetors because the cross-drilled holes often become plugged up. When this occurs, the fuel mixture cannot be emulsified properly (mixing fuel and air before being discharged through the outlet opening) and you wind up with performance issues because of the blobs of fuel being drawn into the air stream of the venturis.

The carb body and all the little bits were immersed in a small can of Berryman’s carb dip, which isn’t quite as powerful as it once was, but generally does a pretty good job of cleaning out varnish deposits. While waiting for carb components, my attention returned to the rest of the bike, where I can spend time adjusting the valves, checking compression, adjusting the camchain (and there is a TSB bulletin about replacing the camchain tensioner components) and cleaning the points in advance of an ignition timing check and any necessary adjustments.

My observations about the originality of the bike’s components left me wondering how the nearly bald rear tire and half-worn out rear brake shoes (based upon the position of the brake adjusting rod nut) could have suffered so much wear in just 900 miles. The tires were obviously the factory pair of Bridgestones, but the front, ribbed tire showed little wear in comparison to the ragged rear tire. Unlike the previous CL350-450s, which carried 19” front wheel/tire assemblies, the CL360 (made for only two years) had 18” hoops on both ends. The 300 x 18 front and 3.50 x 18 rear tire sizes were exactly the same as those on my 1981 CB250RS single, which weighed about 100 lbs less that this 360cc twin.

The 360cc series of bikes replaced the previous 350cc models, but in an entirely new design. Where the 350s carried the camshaft bearings on end caps, the 360 had a full-width cylinder head, not unlike a four cylinder model, still with plain bearings in the head cradling the camshaft support loads. The main design feature was the relocation of the tachometer gear drive from outboard to inboard the right side camshaft lobes. The 360s (except for the “café-version” CJ360) had new 6-speed transmissions installed to help spread the power across the range while allowing for a taller final gear step. These engines did not receive any counter-balancing engineering, so they shake a little more than their 350cc forbearers. The vibration issues were not resolved until Honda built brand new CB400T twins in 1978, which did feature a chain-driven counterbalance system to offset the 360 degree crankshafts installed in those new models.

Whereas all the previous twins had separate carburetors mounted to each intake port, the 360s had their carburetors ganged together on a mounting plate, which allows for more accurate synchronization and the use of the mandatory push-pull double carburetor cable setup. This safety feature necessitates more complexity in connecting the throttle plate shafts together. The link which connects the two shafts together is a hollow square tube, with holes drilled into the side and one end has a threaded hole for the end piece. There are four little ball sockets, a long spacer, a spring and lockwasher/nut, in addition to two small flat nylon washers and e-clips to help secure the whole assembly together.

There was some cause for alarm when an etched away part of the threaded boss where the idle mixture screw cap threads down into the body. It looks as if the end cap is threaded far enough to cover the threads below and seal off the jet from outside fueling, but the whole thing is marginal, at best. One of the carburetor floats, which have phenolic float ends, had a portion of the plastic material eaten away, which may well cause the float to absorb gasoline and start to sink.

There are five different calibrations for these carburetor sets; however the aftermarket carb kit makers only chose to make a generic one with just the #100 main jet and a #35 idle jet. The later model #754A carbs use a #110 main jet. Neither of the available repair kits include a primary main jet (normally #68), however the jet selections for the multiple calibrations of the Honda 350s is much worse as their calibrations range all over the place.

DAY TWO

Parts, ordered on Friday afternoon, from two different sources, arrived in Monday’s mail advancing my plans for getting the CL360 into operable condition. The used slide/diaphragm assembly arrived in a VERY large Priority Mail box, while the two carb kids came in an envelope. Methodical cleaning of the carburetor bodies and jets allowed nearly complete reassembly of the carburetor set, fully mounted on the base plate. After installing the slide/diaphragm into the right side carburetor, the rebuild task was complete for the moment. A few days of the float bowl o-rings sitting out in the hot sun allowed the alcohol to be released from the material and the bowl gasket reinstalled into the bowl groove with a dab of silicone grease placed in a few key locations. I attempted to seal up the surface of the float with some blue Lock-tite, which may just dissolve in the fuel when the bowls are refilled, but it was worth the experiment.

The carburetor rack fits easily into the frame and onto the inlet manifolds, once the battery box is out of the way. The throttle cables installed with relative ease, as well. I was relieved to discover that the left side air filter assembly does install into the frame without removal of the exhaust system! And the left side cover also slips into place without the need to wrestle the pipes out of the way. Honda finally got it right for the Scrambler twins!

With carbs and air filters all installed, the bike was nearing the fire-up stage. I had previously checked valve clearances and ignition timing, so this was about the last stage of the repair cycle. Installing the Brand –X battery, which had been cooking overnight on the charger and read 13v before it was hooked up, suddenly went to 7v when the starter button was pressed. BLAH! A quick call to the closest Honda dealer, over in Lemon Grove, CA yielded positive results for my battery request. They began to service the battery by the time I had hung up the phone. Rushing across town with the old battery in hand, I gladly exchanged it with a fresh power source and headed back for home. Ideally, a freshly-serviced battery needs about 3 hours of standing time; then it can go on a charger for another 5-6 hours at about a 1 amp rate. I was in a hurry, so chose to just kickstart the bike once the fresh battery was installed.

The fuel petcock had already been replaced with a new OEM unit, which showed little signs of serious contamination from old fuel or rust. There was some rust bits felt in the roof of the fuel tank, but nothing of great concern. The new petcock has a little screen over the RESERVE feed portion of the unit, so it will screen out any floaters for the most part. My primary job was to get the bike running reliably and within a preferred $500 budget. With a couple of gallons of fresh fuel inserted into the fuel tank and the fuel lines all hooked up, the choke was placed in ON position and a few sturdy kicks brought the bike to life, first stuttering and dying, then recovering to a fast idle once it was kicked a couple of more times.

The first few minutes of a bike’s awakening can be critical for components inside the engine which haven’t seen lubrication for 10-20 years. Keeping the idle speed around 2-3k rpms and listening intently for any signs of lubrication failure led to no concerns. The right side carburetor float valve seemed to be having some closing issues on and off, but once the bike was running the vibration and a little rocking back and forth seemed to allow the float valve needle to settle into place, as designed.

One quick lap around the block reminded me to bring it back for a tire pressure check, as the bike seemed to fall into left hand corners more easily than when turning right. Air pressures were sub-20 and the rear axle marks were off about 1/8” from side to side. The drive chain had been over-tightened, as well, so loosening the chain, aligning the axle and a little bit of chain lubrication put things right again, once the tire pressures were brought back to normal. A longer follow-up ride gave more confidence and joy to the experience. The bikes sound quite a bit like their 350cc brethren, but the extra 6th gear closes up gear spacing gaps and gives it a more relaxed cruising speed. I did detect some vibration phases around 4,500 rpms, though, which is to be expected for a non-counterbalanced engine. Throttle response was good, idling was nice and smooth with little in the way of engine noise at all.

The bike did seem to suffer from some clutch drag, as finding neutral was just as vexing as it was on the last CB350 twin I serviced a few weeks ago. The clutch wasn’t “stuck” once the engine fired up, but I suspect that it may have been at some point in time. My “solution” was to drive the bike about 30-40 mph and fan the clutch about a dozen times, allowing it to slip and hook-up repeatedly. It isn’t the kindest thing to do to an engine or clutch, but I surmised that it might knock off some of the rough material that usually attaches to the steel clutch plates when the clutch is compressed for years at a time. Stopping once to turn around, the neutral selection seemed to improve. I tried the same tactic again on the return drive up a long grade, at 50 mph, fanning the clutch a few more times.

Once home, the oil was changed, which remains a messy task on the 350-360-450 twins of that era. Honda used a 22mm drain plug which causes a flood when it is removed from the engine cases. After draining the used oil into a collection pan, I discovered that whoever changed the oil previously had failed to replace the sealing washer. The plug was not leaking, but I didn’t want to chance it without some kind of washer. A trip to the local O-Reilly’s auto parts store offered only two options: pay $14 for a “Dodge Truck” 22mm drain plug and rubber gasket or try out the GM carburetor inlet packing set for $2.99, which had some suitable, but narrow, fiber washers of the right diameter. I chose those and it seemed to work fine for this emergency application.

As I was sending an email report to the owner, I received one from him stating that he was shipping a 3.25x18 rear tire to me for replacement of the nearly bald OEM rear tire, so the party isn’t quite over just yet.

You don’t get many chances to experience a near-new vintage Honda in its original form. The bike runs fine and sounds as good as you would expect one to be at 900 miles, but it holds no special charm for me, as a potential owner in the future. It is destined to return to Costa Mesa in a few days, where it can charm the locals with its originality and uniqueness; as a low-mile, low-serial numbered, classic Honda CL360 Scrambler.

Bill “MrHonda” Silver