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Discussion Starter · #1 ·
I have read how the Honda DOHC twin invasion nearly or
did kill the British motorcycle industry. I believe these
included 305, 350, 360 and 450 models. Maybe also 250cc
twins as well. I am just a beginner so please excuse. One
thing I see repeatedly stated is complaints about vibration
and I wondered if or when honda first used balance shafts
in their motors. It appears that in the last twenty years
or so many mfgrs have figured out how to smooth large
capacity single cylinder cycles such that today they predominate
I assume because they are cheaper to build and sell. I am
thinking the secret weapon here is the balance shafts used.

Anyone that has worked on a lot of these engines over the
last 40 years probably knows the answer and I would appreciate
some clarification.

Thanks from Atlanta, GA
 

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The 450 was the initial big blow to the British bikes, but the real death knell was the CB750 4 cylinder in 1969. The later SOHC 400/450 series engines had balancers in them, not sure if they were the first from Honda to have them. Since you're now a member, please take a look at the link below and post an introduction so we can get to know you and your bike better to be of better help in the future

https://www.hondatwins.net/forums/23-member-introductions/121120-critical-read-before-posting.html
 

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Kinda funny though.. I have first hand experience with both Triumph (650s)AND Hondas (450s)... Old Triumphs have a huge "tollerance" and motors can be literally "slappped together".. and run.. not saying how well, but they will run.. as for VIBTATIONS, there is plenty!! The only way I have found to reduce it(noticed I said reduce), it good valve adjustments, ignition timing, and carboration balance. My old 650s fire at 180 degrees.. depending on RPMs and load the vibrations will vary.. 50mph isn't to bad, higher speeds aren't as friendly. My moto and handlebars are hard mounted (no insulators), I have read about guys filling their handlebars with "rubber" or dense material in an attempt to reduce hands going numb.
My 450dohc.. same with basic good tuning practices, I'm still learning this motor, not sure about the firing degrees... but it is a joy to ride compared to the Triumph!
Recently I attended a show in Savannah (Victory Moto Show) and a manufacture was showing thier line of bikes (vintage appearance w/ newer single piston drivetrain). This incorporated a counterballance, and was said to be smooth..
NOW.. my new Triumph Bobber.. 70-80-90mph... I swear it's like a sewing machine.. smooth as it gets ..well, as smooth as I have experienced, I'm pretty damn sure Honda has got this beat somewhere...
I sold my 2016 softail slim to obtain this bike... I read reviews, checked it out and honestly it was 99% on visual design...
I honestly believe Triumph saved their company on "re-release" of the Cafe Racer / Theuxton design several years ago and the recent designs from the past couple years...
Honda had got the "motor", tolerance, and attention to detail (engineered / assembly) down to a science.. proof is in the pudding.. what other manufacture has this many (name a product here) from 30-40-50-60 years prior still in operation and IN DEMAND!
If Honda sold a Vintage styled bike (visually), with a modern drive train.. I think it would be a major game changer..
Making a "old bike" more enjoyable to ride and enjoy... sign me up..
Classic autos have adopted this for quite some time, labeled and "resto-mods"... Not sure if it would be well received in the motorcycle world. A EVO motor shoved into a 46 flathead body/frame would probubly have Harley purists up in arms.. but motor internals.. THAT my be another story...
 

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Discussion Starter · #4 · (Edited)
Can we assume the parallel twins from Honda before 1974 did not have balance shafts.....
from the magazine review below.

Excert from Old Magazine review 1974 Honda 360cc Scrambler twin engine

https://ridermagazine.com/2015/10/30/retrospective-honda-cl360-scrambler-1974-1975/ f

Honda presented three 360 models for 1974, all under $1,000. The CL street scrambler ran for
two years, 1974-1975; the plain CB, with drum front brake, for one year, 1974; the CB/G, with
a disc front brake, for one, 1974. The CL had the “American-style” upswept pipes running
along the left side, a 2.9-gallon gas tank and drum brakes fore and aft.
Road testers of the time had varied opinions as to the rideability of the 360. The one constant
complaint was about the VIBRATION of the 180-degree twin. The 350 had been a shaker, and the
360 wasn’t any better. Also, the engine had been detuned in order to enhance the torque, so
while the 350 boasted 36 horses at 10,000 rpm, the 360 was down to 34 at 9,000. Honda felt
that this less-peaky engine would make the bike more fun to ride around town. It was definitely
a short-haul machine, as nobody seemed to like the saddle for long trips.

Internally the bearings on the crankshaft had been strengthened, and those who enjoyed
abusing their engines were less concerned about bottom-end problems…not that the 350 had
really had any. More important to the home mechanic, and most owners of the 350 who did
not have the money to pay a professional, the obnoxious oil slinger that passed the lubricant
through a filter was redesigned to make access to, and replacement of, the cleanable filter
much easier. The whole oiling system had been substantially changed, using a “trochoidal”
pump that utilized pressure rather than the previous splash system. Looking up trochoidal in
the dictionary doesn’t help much, but it appears to be more or less a five-sided Wankel-type design.
The tensioner on the rather long chain driving the single overhead camshaft had also been altered,
as the previous roller-wheel design had often been over-tightened by inexperienced types,
leading to disastrous endings. Now there was a simple slipper-type adjuster, easier for the casual
wrench-wielder to do properly. However, a recall in April of 1975 was due to malfunctioning slippers,
and dealers would install a new version, which worked well.

Adjusting clearances on the four valves was simplified by using setscrews at the tips of the
rocker arms secured by old-fashioned locknuts.
Major change was in the two carburetors—instead of the previous slide types, the new ones were
of the constant-vacuum variety—and test riders complained about them being too sensitive.
The throttle now had twin push-me/pull-you cables, but at slow speeds the carbs were blamed
for the lack of smoothness. The rubber blocks in the rear hub, which were intended to ease
tension on the chain final drive, were considered by some a bit too soft, contributing to jerkiness.
Straight-cut gears went from the crankshaft to the transmission, which now had a sixth gear.

A number of riders felt the extra gear was unnecessary, as too many gears can be as frustrating
as too few. Ride reviews found some testers complaining that the gears were now too closely
spaced; others said the spacing was perfect. You can’t please all the people all of the time.
The most important change was the new tubular frame, with a single downtube, splitting off
to create a cradle under the engine. Of note was the improved quality of the welds in the
frame; their aesthetics were a couple of notches above what people had been used to seeing
from Honda. Some ride reports said that, when ridden hard, the 360 tended to flex a bit
more than was pleasurable; others lauded the “superb chassis.”

CL sales not being up to expectations, it was dropped from the line after two years, while a
CB/T model, with minor cosmetic changes from the previous G, continued on in ’75 and ’76.
Then Honda decided to retrograde the bike, coming out with the CJ360 model, which had
no electric starter, drum brakes fore and aft and a 5-speed transmission. The two-into-two
exhaust was changed to a less costly two-into-one running out the right side, and the
centerstand was deleted. And the price lowered.

But that was just a stopgap until the CB400 appeared in ’78, the parallel twin bored out yet
again, this time to 395cc, and sporting a new three-valve, OHC head, with a pair of "COUNTERBALANCERS"
to quell the vibes—and a 5-speed transmission. Maybe that sixth gear was not necessary.
 

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FYI, the only DOHC Honda twin of the era was the 450. The smaller twins (305, 350, 360, etc.) were all SOHC.
 

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The only vibration-reduction device that works on these bikes is called an "ignition key" - turn it all the way counter-clockwise, vibrations will stop.
Realistically they're no worse than a lot of old bikes.
 

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It might sound simplistic but the best thing I did on my CX and CB to reduce vibration(I discovered this by accident) was adding bar end mirrors. Just having the added weight on the ends of the bars made a big difference.
 

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IMG_7478.jpg
For all those wondering just how long they have ridden...:)
 

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Discussion Starter · #11 ·
OK to really drill down here. I am in the hunt for a smallish/medium on/off road bike capable of minimum hwy use.
I have decided that I ONLY want to consider bikes that have balance shafts. What Honda models and what years of
singles or twins have balance shafts ? The magazine review above says the 360CL had a balance shaft but obviously
lots of others use them as well. What would those models be ?

To me I would also like to know which models to avoid if Honda made any later singles or twins without balance shafts.

I am kind of surprised that the existence of balance shafts is not more highly featured in mfgr literature and specs listings for
each model etc. Unless of course ALL newer motorcycles use the balance shafts and I dont think that is the case at least
with some of the smaller single cylinder motors.
 

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https://www.janusmotorcycles.com/
Give this a look.. this is the manufacture that was at the show..
Great concept, cool designs, the 250cc doesn't appeal to me, and the price is a coffin nail....
But you can't dispute.. it is cool as hell riding a bike that has a 1920s "board tracker" appearance with a reliable new drive train!
 

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OK to really drill down here. I am in the hunt for a smallish/medium on/off road bike capable of minimum hwy use.
I have decided that I ONLY want to consider bikes that have balance shafts. What Honda models and what years of
singles or twins have balance shafts ? The magazine review above says the 360CL had a balance shaft but obviously
lots of others use them as well. What would those models be ?

To me I would also like to know which models to avoid if Honda made any later singles or twins without balance shafts.

I am kind of surprised that the existence of balance shafts is not more highly featured in mfgr literature and specs listings for
each model etc. Unless of course ALL newer motorcycles use the balance shafts and I dont think that is the case at least
with some of the smaller single cylinder motors.
I'm a bit confused, are you looking for a vintage bike to modify for your needs or are you trying to buy something that meets your criteria?
 

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The magazine review above says the 360CL had a balance shaft
No, that isn't what it said - your own quote of the article was this:

"But that was just a stopgap until the CB400 appeared in ’78, the parallel twin bored out yet
again, this time to 395cc, and sporting a new three-valve, OHC head, with a pair of "COUNTERBALANCERS"
to quell the vibes—and a 5-speed transmission. Maybe that sixth gear was not necessary."

400, not 360.jpg

The article is seriously flawed in that the 360 was not simply bored out to make it the CB400 with a 3 valve head added along with counterbalancers... the 400 is an entirely different engine, from the plain-bearing bottom end to the hyvo-type chain used for the cam chain instead of the previous roller chain to the in-frame disassembly-capable top end, and probably more differences that I'm not familiar with because I've never owned or worked on one. And, I don't know if the author of the article ever cleaned the supposedly-replaceable new design oil filter arrangement on the CB/CL360 either, as it wasn't replaceable and wasn't any easier than the 350, in fact in some ways more difficult as the entire right engine cover had to be removed unlike the 350 before it. as far as I know, the CB400 series was the first Honda twin to have balancers in it. I don't have all of your answers, but the internet is riddled with falsehoods about these old vintage bikes - even by some companies that are vintage bike parts suppliers themselves. Don't take everything you see on the internet about these bikes as truth.
 

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Dont know much about the other bikes but the only vibration- reduction device on my 350 was my butt. At speeds pushing 80 mph it would go numb.


Bill
 
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