Advantages of the V4 engine configuration?

Cunados said:
There are numerous possible engine configurations Honda could have chosen for the ST1300. They chose a 1,261 cc longitudinal V4 fuel injected DOHC 4 valves per cylinder engine. Yamaha, Kawasaki, BMW and Triumph, to name a few, chose different paths.

Here's my question: What are the advantages and/or disadvantages to a longitudinal V4 when compared to the other manufacturers' ST engine configurations?

If I'm not mistaken, the ST1300 is the only current Honda model to use this engine configuration. I would suspect there is a reason. I wonder what it is?

Any insight would be greatly appreciated.
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Longitudinal so that they could fit a fuel tank that would meet the range requirement.
 
At the risk of repeating what others posted, the V4 in an ST1100/A/P has "perfect" primary balance and lots of torque at low revs, but that's just the beginning. The short length makes for a shorter wheel base and/or moves the big fuel tank down behind the engine, for less top heaviness. I'm still not done.

The ST's V4 is located way lower than any transverse 4 because much of the engine is below the lowest frame member. And Honda pushed the engine up as close to the front wheel as is possible with liquid cooling. (BMW failed to do so with their ill fated K75 triple.) All of that helps with quick steering, good front wheel traction, and low CG. I don't know the ST1300 very well.

(By the way, Honda said much the same thing at the intro of the ST1100. Maybe I trusted their hype a bit too much?)
 
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Also, they say that the Clutch and the Alternator rotates in the opposite direction than the crankshaft, to help control some torque reaction present in longitudinal engines.
 
You can think of a V-4 engine as either two V-twins or two parallel twins, which share a crankshaft. Each of those engine types has certain type of primary balance, so the advantages of each seem to mesh well.

What I found interesting the first time I saw it in a drawing in the Clymer is that both of the crankshaft throws are at the same degree of rotation, i.e., each pair of the parallel pistons rises and falls together.

That gives each pair the 180-degree timing of a vintage British twin instead of the 270-degree timing of a vintage Japanese twin. The V-cylinder pairs have the usual 90-degree V-twin primary balance.
 
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Ilbikes: I will say that it is the most top heavy bike I've ever ridden.
Wow, I haven't heard that claim before, but I respect it.
My personal view only: The low CG 'feel' is one of the many features that attracted me to the ST. Certainly my FJR1300, and even my Suzy 1250, 'felt' top heavier than the ST when manoeuvring them around my garage. But all of them including the ST are no light weights. To me the ST is a beautifully balanced machine, slow or fast, and gives me a feeling it is ready and willing to be controlled and do as I ask (within reason).
D
 
GryST said:
The ST is happy to turn and lean in corners, Bandit fights me. I have to put more force, and even with that is not as the ST. Don't know, maybe it's just mine. Tires are new and air pressure is fine. Good balancing and alignment...
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Okay, that's exactly the experience I had when I first got my ST. It resisted leaning in response to counter-steering input effort, and trying to apply more torque resulted in unpredictable turning. The previous owner weighs less than I, so after hating the handling for a couple of months, I raised the rear suspension about 1/2" at the shock, which probably raised the ride height around 3/4"

The results were immediate and profound. By raising the rear, the steering geometry angle steepened, increasing steering response. The bike now leans and comes back up easily and predictably. Soon after, when I picked up the ST after having new tires mounted, the handling was so wobbly, I thought I would have to lower the rear again, but I got used to it before I got home that day.

So, don't be so sure that the issue is the bike itself. The steering geometry changes with ride height, which changes with weight. Try raising the rear suspension, while keeping track of the adjustments you make, so you can return to a previous setting if you don't like the results. I have the feeling you will be able to improve the handling quite a bit this way. Let us know what happens.
 
GryST said:
Thanks for the suggestion, Larry. I was playing with the read (and front) suspensions. But I think maybe rear is getting old. It has 1 to 7 levels and now I'm at 7th now. Started at 3 and gradually went up after each setting became more wobbly on bumps especially in turns under load. At level 7 it's still feels ok for now but not great. Still handling didn't improve. Bike is at 55k miles. maybe I need a new suspensions just don't like to invest heavily.

As for the ST, I recalling when I bought it, the handling was bad. Plus right turns were worse than left. Replaced tires with Bridgestones T31 and (very important) had to do a good tire balancing. First balance on rear was not too precise and the bike wanted to throw me off over 70mph. After the rebalancing I had a new bike. But it had only 10k on. Not so with Bandit.
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When you counter clockwise back off all the preload to the Soft or 1 setting and then crank it clockwise to add preload does the adjuster wheel encounter resistance by a turn or two? As you know from being here the preload adjuster loses ability to actually add preload over a length of time but a simple service of the adjuster restores full travel to it. If the last line 7 now does what 3 used to it sounds like the adjuster needs refilling. At 55k the shock should still work well, at least not markedly worse than new.
 
I wasn't pleased at first with my ST's handling either. I then remembered the PO's suggestion to run the "A" model's big front tire at a higher psi, I find it much much better at 40 (or maybe I have to lose a few lbs)
 
DaveWooster said:
At the risk of repeating what others posted, the V4 in an ST1100/A/P has "perfect" primary balance and lots of torque at low revs, but that's just the beginning. The short length makes for a shorter wheel base and/or moves the big fuel tank down behind the engine, for less top heaviness. I'm still not done.

The ST's V4 is located way lower than any transverse 4 because much of the engine is below the lowest frame member. And Honda pushed the engine up as close to the front wheel as is possible with liquid cooling. (BMW failed to do so with their ill fated K75 triple.) All of that helps with quick steering, good front wheel traction, and low CG. ...
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Focusing on the longitudinal mounting, the engine looks somewhat like an inverted triangle when viewed from the front or rear. Its width at the top doesn't bother a rider. Its narrowness at the bottom gives two advantages, compared to a flat four or six. It does not spread the rider's boots apart, and in a curve, it gives better clearance; it allows more lean angle.
 
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DaveWooster said:
Focusing on the longitudinal mounting, the engine looks somewhat like an inverted triangle when viewed from the front or rear. Its width at the top doesn't bother a rider. Its narrowness at the bottom gives two advantages, compared to a flat four or six. It does not spread the rider's boots apart, and in a curve, it gives better clearance; it allows more lean angle.
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At a stop, a flat four or six prevents the rider's legs from having a straight shot at the ground.
An ST1100's V4 does not.

And ample cornering clearance leaves room for engine guards, which protect the otherwise vulnerable cylinder heads.
 
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Chris_64 said:
So, for those who might want to dig the subject from the start...
Here is a simple introduction video on youtube, explaining bore size, stroke lenght, Inline four vs Vee, Torque, Crank Shaft lenght, etc.
Why a V4 engine ?
Chris
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Hilarious video but informative too - there's something about that Monty Python way about him - laced with profanity ... :rofl1::thumb:
 
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Thread summary:

When it comes to bike engines,

Two heads are better than one.

And when it came time to design the overall ST1100 Series, two heads where better than one then, also. (Japan teamed up with Honda of Europe.)
 
Chris_64 said:
Here is a simple introduction video on youtube, explaining bore size, stroke lenght, Inline four vs Vee, Torque, Crank Shaft lenght, etc.
Why a V4 engine ?
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I just watched it. Entertaining and informative. His accent reminds me of the father in Shallow Hal.

Jeff F said:
Hilarious video but informative too - there's something about that Monty Python way about him - laced with profanity ... :rofl1::thumb:
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It's even better when you watch how the closed captioning interprets his "fookin" English.
 
I had a guy today ask me at a stop light.... is that a car engine? I had to laugh as I explained no it a V4 motorcycle engine. I think Honda just picked this engine configuration just because they could. They already had a flat 4 and flat 6. V twin engines mounted across the chassis and longitudely. Turbo charged engines, in line 6's air cooled and in line 4's air cooled and the liquid kind. I guess Honda did not want the same old engine design for their new flagship sport touring motorcycle.
 
I'd guess it makes sense to have the crankshaft driving inline with the drive shaft, ? I'm no engineer - sparky by trade
 
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