First of all these are just the opinions of one person and not meant as advice or technical information. You know your own bike. Please let your own common sense prevail. Do not take this as gospel. It is not.
For CB350 owners. If you pull the little cover to clean out the centrifugal oil filter make sure to be extremely careful to put the cover back in the proper position otherwise you can melt the top end down. Also try replacing those old stripped out case screws with easily available allen head machine screws. You will save a lot of heartache and the need for an impact driver every time you want to do anything to the bike.
If you can get some good shocks, have your swingarm re-bushed, get some good tires (I prefer Avon Roadrunners), try to find a nice Marzocchi front end, and get some good quality heavy metallic brake shoes - you can get rid of many of the bike's worst traits and have a nice little machine when you are done.
Secondly, a question that most CB350 owners wonder at one time or another is "why does my battery need to be replaced every 7500 miles?" Without getting into heavy battery talk it works like this. When a battery is being discharged, the sulfuric acid in the electrolyte is being depleted so that the electrolyte more closely resembles water. At the same time, sulfate from the acid is coating the plates and reducing the surface area over which the chemical reaction can take place. Charging reverses the process, driving the sulfate back into the acid.
The alternator on your CB350 is too small even with kick start only. So it never fully reverses the process and therefore lead sulfate just continually builds up between the plates and kills your battery. If you trickle charge the battery once a week with a good charger (like the one made by Yuasa) your battery will live much longer.
About the Honda CB350 twins (and the CL350 scramblers). At one time the Honda CB350 was the most popular bike in America and in fact at one time one fifth of all the world's motorcycles were Honda 350s! To understand this you have to go back in time a bit.
By and large America was new to (and falling in love with) motorcycling. These were the days of and Evil Knievel and motorcycling was everywhere. Kawasaki was letting the good times roll (if you did not bite it on an H1) and Honda was building small, reliable, and unintimidating motorcycles that for the first time were making motorcycling socially acceptable.
A Honda motorcycle was not some wild two stroke on the edge of control, it was not some oil dumping noisemaker, it had electric start, and it was smooth, quiet and reliable. Many were discovering motorcycling for the first time and did not want a 130 mile per hour bike with narrow tires, and a rubber frame. They did not want a bike that weighed 500 pounds and was as wide as a building. Many people were not ready for a Z900, a CB750, or a Suzuki Water Buffalo.
People percieved the Triumphs, Harleys, BSAs, and BMWs to be troublesome and oil leaking monsters (If you have ever had a kickback from an improperly timed 500cc Matchless single cylinder that threw you over the handlebars you may not want another Brit bike again) and it was either BSA or Royal Oilfield (oops Enfield) that even offered a type of diaper that you could attach to the bottom of their horizontally split cases to soak up the leaking oil. As one friend of mine in the Euro bike shop that I worked at told me "oil on the outside means oil on the inside".
The Japanese cruiser, the super sport (as we know it today) and the monster tourer were not in the Japanese inventory at the time. There was a massive fuel crisis and people wanted anything that got good gas milege. Many of those people bought Honda CB350s.
Why? You might ask. Was it the Suzuki GSXR, the Honda Goldwing, and the Kawasaki Vulcan of its day all rolled into one? Was it some form of uberscooter (superbike) of its time? The answer is very much, NO! The Honda CB350 in reality does nothing well. The forks are absolutely minimal, the fork tubes are like metal toothpicks by modern standards and the valving is terrible. The rear shocks are mere spring-holders with no damping at all (this is further worsened by a clevis type setup that makes them a bear to get any decent shocks for). The frame geometry is just bad and the stock tires were pretty pathetic. The brakes are nothing great with a front drum that is tiny and a rear brake lever that transmits more force to the side than it does to the rear brakes as it runs under the bike.
The alternator is too small. Even though they had good CD ignitions at the time the bike has a dual point set-up requiring constant maintenance. In fact, even for its day and its displacement, the Honda CB350 did not make a lot of power by any means.
As to comfort, the suspension bottoms out easily, you feel every bump that you hit, there is plenty of swingarm flexing in hard turns and the engine power does not come on until 6500rpm so you get buzzed pretty good.
Also there are other issues with such things as clutch drag, false neutrals, and a notchy gearbox that requires you to slip the clutch to downshift the bike to keep the transmission from locking up (making it impossible to get the bike into neutral). This is a realistic view of the bike in its day. Even at the time there were many bikes that were much faster (the H1 Kawasaki for one), many bikes that handled better (the Nortons of the day), and many bikes that were much more comfortable, with lots more tourque and much better long-distance-riding manners for touring (such as the BMW Boxers and the Triumph Tridents of the time).
So why was the Honda CB350 so popular? To help to answer this let's look at the small bikes of today. Imagine that you want a bike that gets good milege. You want to use it to go to work and back (maybe ride two-up and go for a ride in the country now and then). You are not an enthusiast (yet) and you are not going to spend big money for one of "those things". You see the big Japanese bikes with their twelve thousand dollar price tags and they are just simply way more than you are willing to spend for a sport that you are not even sure that you will enjoy. You think of the American or the European stuff but once again you do not want to lay out twenty grand for a bike.
You decide to get something smaller and Japanese because of a reputation for reliability and affordability. You look at Suzuki. You walk into the dealership. You see the Hayabusa 1300 and it frightens you. You look at the big and heavy Cruisers and Tourers and the Crotch Rockets ... not for you. Then you see this friendly little GZ250 with it's low seat height, its light weight, and its single cylinder engine and you think "hmmmm for 2999.99 dollars I could do that".
Now you go to Honda and look at the Goldwings and the VFR's and think that these are not for you but maybe for 3399.99 dollars you might be interested in the little 250 parallel-twin CB250 Nighthawk with its familiar standard configuration, its dual shocks, and its drum brakes.
Then you go to Kawasaki and look at the big stuff but and while doing so you find something amazing! For only 2999.99 dollars you can get a small bike with big bike features and engineering. You can get a water-cooled 250cc four valve per cylinder, dual overhead cam, two cylinder, four stroke, with tons of power, a smooth six speed gear box, a 14000 rpm red line, an easy neutral finder, you get modern disk brakes, a great frame, a state of the art link type suspension, plus sport styling that rivals the nicest bikes out there, and the Ninja name on it.
This is not some corner cutting budget bike but a real machine. It has a 4.8 gallon tank, a long production run, it is reliable and easy to maintain, it is fun to ride, super versatile, and a great handling machine. So you like many other people purchase a 250 Ninja. It doesen't matter to you that the Suzuki Hayabusa is faster, that the Honda Goldwing is more comfortable, that Kawasaki ZX7 handles better. The 250 Ninja is the right bike at the right time for you. It will go faster than you want to, do all you need it to do, and achieve better lean angles than you will ever push it to...
Now imagine that the Suzuki GZ250 and the Honda CB250 do not even exist at all. What bike would you buy? So it was with the Honda CB350 - it had the prestige of the Honda name, it had electric start, it had an overhead cam, it was cheap, it was reliable, it was easy to work on, it was not some noisy smoking two stroke or some massive monster, it would ride two up, with the luggage rack you could go shopping or go to work with your briefcase, it cornered well enough for you, it was predictable and well mannered it had a twin leading shoe front brake (a very good brake for the time). It did everything that you wanted it to do and everything that you wanted a motorcycle for. It was the perfect bike for you at the perfect time for you.
This was not some corner cutting budget bike but a real machine with all of the big bike features you wanted in a sporty and unintimidating package from a manufacturer that you (and others) trusted. There were more new riders at this time that at any other and if you were new to street motorcycling in 1972 chances are you bought the Honda CB350 because there was just nothing else at all quite like it. Even to this day in the year 2002 people still commute with, shop with, and ride thirty year old CB350 Hondas because while they don't do anything well they will do everything ok and that gives them a utility that has transcended time. It does not matter that the new bikes are faster, smoother, more powerful and better handling. You do not ride a CB350 to own the best. You ride it beause it will do everything that you need it to do.
That is why the CB350 has earned a place in motorcycling history and a place in peoples hearts. When it was new it was like the modern equivalent of a Ford Escort, a Toyota Camray or the Volkswagen Beetle. Those cars may not handle like a Ferrari, they may not be as comfortable as a Lincoln, they may not have the prestige of a Mercedes Benz, but they sure do sell a ton of them every year and many people have fond memories of the things they did and the times that they had with those cars.
The CB350 is the bike that got people into motorcycling. It boradened the appeal and helped to make motorcycling the sport that it is today (instead of the underground realm of greasy garages and smoky taverns that it once was). That is why the Honda CB350 (like the air cooled Volkswagen Beetle) has endured through the decades and can still be found with us today. I hope that this helps you to understand the Honda CB350 a bit better.
About the author: I am a certified motorcycle mechanic. I have been riding for over 16 years. I have owned five Honda CB350s. I have owned big Yamahas, Suzukis, Kawasakis, and even a few Truimphs as well and I have found this to be true: no matter what a person rides - if they are riding a 125cc two stroke or a Honda 250 Rebel - they are still out there on two wheels sharing the same joys and the same dangers as the rest of us. That person having fun riding their GZ250 single cylinder cruiser is more of a motorcyclist than the person who will never get any closer to a bike than a tee-shirt and a sticker in the back window of a pickup truck will ever be.
So please, we get enough flack from the Government, from the safety folks, and from the car drivers - let's not give flack to each other. It doesn't matter what we ride. Only that we ride at all. Rubber side down to All.
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First of all these are just the opinions of one person and not meant as advice or technical information. You know your own bike. Please let your own common sense prevail. Do not take this as gospel. It is not. The Honda CB350 is one of the best selling (at least here in America) motorcycles of all time for many good reasons. Part of it was timing. At a time when many motorcycles had the reputation of being oil leaking noise machines ridden by people who were one step away from being back in prison or wild two-strokes with flexi-flyer frames and dubious reliability, there was Honda. There was the perceived quality. The perceived reliability. The good road manners of their well made four stroke machines and most of all the marketing genius and success of the ad campaign. "You meet the nicest people on a Honda".
The early seventies were the heyday of American motorcycling. Motorcycles were everywhere and there were more new motorcyclists than at any other time in American history. Honda was the motorcycle to buy and the motorcycle that people wanted. A new motorcyclist could look at the H1 Kawasaki but many people did not trust or want a two-stroke which could be unreliable and back then the power bands were either on or off so they could be very hard to ride. The Z1 Kawasaki and the CB750 fours were nice machines but they were huge, intimidating to most people and also rather expensive at a time when most bikes were singles or twins and not across the frame fours.
To the people of the day the CB350 was in the right place at the right time to be the perfect ride for the masses. The Honda CB350 was not too big and not too small. The bike had plenty of power for most people. I have owned eight of the machines and done two-up touring with them many times. You could get (and even to this day still can get) an endless array of accessories such as luggage racks, pipes, sissy bars, chopper frames, racing frames and anything you wanted to customize these amazingly popular machines in endless ways. They are even to this day a very popular bike to build for vintage racing.
The power below 6500rpm was highly manageable and came on in a pleasant rush above 6500 rpm that carried you all the way to the bike's red-line (about 10,000rpm if I am remembering it right). The handling was good and predictable for the time, the bike was comfortable and well laid out, the engine was indestructible, easy to work on, and ran forever. The bike came with many of the features that were associated with much larger machines like turn signals, electric start and a five speed transmission - all this in 1968!
The twin leading shoe brake was excellent for the time, the frame was good for its day, though even back then the forks and swinging arm were a bit on the spindly side. The shock damping was non-existent. The rear shocks were mere spring holders and the front damping was not much better... the bike bottomed out hard on heavy bumps and if you set the spring tension too low the rear of the bike would oscillate badly. Though with today's tires (Avon Roadrunners work amazingly well) a Marzocchi or Ceriani front end, disk brakes, and good shocks on the back and some pretty serious mods you can make them into a very fun cafe racer.
Also under tires... always replace the tubes when you do the tires and never forget to do new rim strips at the same time... bad rim strips can cause you all sorts of grief chasing mysterious flat tires and they cost all of about $1.50 for new ones. The bike has many quirks of which you should be aware if you plan to own one.
The alternator was too small for the bike even when it was new. Also, when the bike was made you did not have to run with the headlight on all of the time. Thus the bike's charging system is simply not up to the task. Because of this the battery is never being charged properly and the batteries tend to either go dead or have a very short lifespan on these bikes. The batteries do what is called sulfating. What this essentially means is that gunk builds up in the plates and shorts them out thus killing the battery. There are a few things you can do to help this. Make sure all of your connections are as clean as possible and replace your battery cables if they are bad, as this will lower the load on the charging system by making its job easier.
Also, buy the best battery you can get and about once a week or so put the battery on a trickle charger for one hour. Use the kickstarter and save the electric start for when you really need it. It is better to use the kickstarter and always have a working electric starter than to use the electric starter until you kill it and then use the kickstart because you have no choice. Doing these things will go a long way to helping the battery to live for a while.
The top ends can be a bit touchy. Make sure to adjust the valves regularly. They are adjusted on simple eccentrics and not so hard to do. Make sure to keep the camchain tension adjusted and be aware of this common cause of top end failure on the CB350 Honda. The bike's oil filter is a bit unique. It is a centrifugal oil filter and to clean it you have to remove a little cover on the side of the motor and then a snap ring - you MUST not alter the position of this cover (provided it was correctly installed). Make a mark on the cover before you take it off. If you install it any way other than the proper one you will fry the top end as it starves of oil and locks up the engine.
Make sure to keep the breaker points and the ignition timing adjusted. Adjusting the points/timing is a major pain on this bike and because the bike is always spinning at seven grand they go out of adjustment all of the time but their adjustment is critical to how the bike runs. Replace those old stripped out case screws with Allen-head ones and save yourself some grief there.
Make sure to keep the carbs synchronized. Make sure that your carbs' CV vacuum diaphragms and carb to cylinder head intake boots are not cracked and leaking. Make sure to keep all of your cables lubed and adjusted and make sure that you have the proper free play in them. Do not mess with the stock air boxes or put pods on the bike, they do not like it with the stock jetting.
Make sure the twin leading shoe front brake is set up right and have a pro do it if you are not sure. Also know that on the front brake and the clutch there are two adjustments. The one at the levers and the one down below. Make sure that your steering head bearings are not baked and that the swinging arm bearings are not wiped out. Make sure that the fork seals are not leaking and an upgrade to progressive suspension springs is a good idea.
Have the wheels trued if you are not sure whether or not they are okay and any damaged spokes replaced. Make sure the fork oil is of the right type and at the right level and make sure that your wheel bearings are in very good condition. Keep them packed and replace them if need be. If EBC still makes shoes for the bike they are excellent and if your exhaust is rotted out Motad is a good source which is available in the United States.
The bike has one major problem... as well made as it was the 5 speed transmission is just plain bad. It is notchy. It locks up. It has false neutrals. The real neutral is hard to find and it requires some finesse to work with. One problem is that you come to a stop, you are in fourth gear, you want to downshift to first but you can't. That is because you needed to have been in first before you ever came to a stop, this is done by pulling the clutch in and pressing down on the shift lever until you feel it click, then letting the clutch out, (one gear per clutch pull), then let the clutch out, pull the clutch in and do the next downshift. For upshifting it is similar - you have to pull the clutch in, upshift, make sure the next gear has engaged, if not pull the clutch back in and do it again holding up on the shift lever until you feel the gear solidly engage or you will encounter one of the many false neutrals that the bike has.
So if you have false neutrals do not panic it is just how the bike was made. A Barnett clutch and 5w/50w Castrol Syntec can help with this situation. But mostly it is a unique skill to work the tranny on the CB350 Honda and in 35 years your transmission may have bent shift forks so that the gears really do not engage properly, worn dogs that cause it to pop out of gear when you give the bike gas to accelerate, or a host of other problems associated with age, wear, abuse, or a combination of all of these things.
Lastly... it is well to understand that the CB350 in some form of perspective. In many ways it's the VW Beetle (the old air cooled ones) of the motorcycle world. Ask yourself which sells more - the Ford Escort or the Chevy Corvette? Answer: The Ford Escort. The Honda CB350 did nothing very well... the beauty of the machine was that it did everything okay. Even in 1972 there were faster bikes, better handling bikes, more comfortable bikes. Bikes like the Triumph 650 Bonnevile and the Norton Commando which could blow the Honda into the weeds.
CB350s are nice bikes to own and ride; they are great commuter bikes. What kept them popular for so long was this: They were cheap and easily obtainable. In 1984 in America you could easily buy one for 50 to 100 dollars and for 500 dollars you could get one with low miles that looked like it just left the showroom. Now sadly people want 1500 dollars for one that a person has to put a ton of money into when for 2500 dollars you could buy a new Kawasaki 250 Ninja which is in the spirit of the CB350 in that it is a small, lightweight, inexpensive, and sporty machine with many features associated with much larger bikes.
But the 250 Ninja's frame, brakes, tires, suspension, electrics, features, handling - and in every other category you can think of - make the CB350 look like some relic from a bygone era (which in many ways the CB350 is). Which is why I now ride a very sweet and fully customized KZ650, these days, which I bought for 300 dollars (about one third the price of the CB350's I was finding when I was looking to purchase one) as a basketcase and rebuilt myself with all kinds of nifty goodies.
The CB350 is a personal experience, a tinkerer's machine, a good first bike, a great way to go to work and back, or some nostalgia for those of us who remember them when they were new. They will not stop on their drum brake like a modern bike, they will not turn on their skinny tires like a modern bike, they do not have the power of a 250 Ninja, they have bad head shakes over 100 mph and if you try to go riding with people on modern small bore sport machines or older but larger bikes such as Nortons, BSAs, Kawi KZ's, or Suzuki GS's you will be pushing the bike harder than it was ever meant to be pushed and the spindly swinging arm, the pencil thin fork tubes, ancient frame geometry, lack of suspension damping, poor valving, skinny tires, drum brakes, and the fact that you have the engine strung out as far as it will go, can all work to get you way in over your head a lot faster that you can handle with no way to recover.
These machines do not like to be pushed. If you are riding with people and you feel like you are pushing the bike harder that you should - you are! - and you need to slow down and find other people to ride with. If your friends give you a bad time about not keeping up, understand that many people have let their pride and ego get them killed. Ride the bike for yourself. Never ride for anyone else. This is important on any machine but absolutely critical on the CB350 Honda.
The CB350 is in reality a 35 year old small bore commuter bike. Understand that the CB350 is (and was in its day) meant to be a reliable commuter, something you can go for a ride with your wife on the back on a sunny day, an enjoyable bike to own and to work on. The bike is not and was never meant to be a canyon carving, tire burning, earth quaking, fire breathing road machine or a loaded down long distance touring ride. Understand that the CB350 is best when viewed as a unique machine and a fine example of an enjoyable vintage Japanese motorcycle or one machine you can use to do everything (like the aforementioned VW Beetle).
If you own one... congratulations! You own a nice machine from motorcycling's yesteryear and if you enjoy the machine for what it really is you will find that one of the greatest joys in life is to own, work on and ride your very own CB350 Honda.
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