Engine noise under load - is it normal?

About engine revs. Yes, at low revs there’s little power, especially in a high gear, BUT, if your just cruising through a village or small town with a 30 or even 20 mph limit, you don’t need any power; there is absolutely no need to be spinning that motor up over 3,000 rpm, let it relax. These things will happily trundle along flat ground at idle IN FIFTH! Sure you won’t be cracking the throttle open in that condition, but you’re giving the engine a rest, saving fuel, and making a lot less noise. It’s also very relaxing, for you, your passenger, and pedestrians you pass. It also makes you look like a responsible citizen and not a hooligan. No one wants to hear a bike ringing it’s nuts off in a 30 mph zone. It’s also very immature. There’s also the issue of piston speed and the greater concept of mechanical sympathy. Why do certain racing drivers always blow up their cars and others always manage to nurse them to the finish? Mechanical sympathy; realising that what you do to the engine, has consequences. If you’re always in too low a gear, your piston speed is unnecessary high. No mater how well the motor is made there are only so many piston revolutions in it before wear becomes apparent. Why cruise at 3,500 in third when you could be doing 2,000 in fifth?…Mechanical sympathy. I’m not suggesting that lugging it everywhere is the answer, in fact lugging it is bad too (highest gear that is appropriate, does not mean lugging), just that, like a car, you should be in the highest practical gear for the conditions and your driving needs. Cruising? relaxing, riding respectfully through town? Keeping your noise down? Switch up those gears and let the engine relax too. Feel the need for speed/rapid acceleration? Snick it down a couple of gears and let her rip. In fact it’s the amazing tractability of these engines (power everywhere and not just at high rpm, like a 600 four) that makes this my “go to” bike for everything. I have a 650 thumper which is much lighter, and flickable and easier to pick up, so it should be my first choice for simply “going for a ride”, but that engine won’t pull cleanly below 2,500rpm, and prefers 3,000. That’s 1.400 to 1,900 higher than where my ST can waft along almost silently in fifth. So, when deciding what to ride, I reach for the ST. Despite its width and weight, it’s still the preferred “exploring “ bike because of that wonderful tractable motor.
Here’s another reason for riding in the highest gear possible; less snatch. If you hit a pothole or bump which causes a rotation of the throttle. Also when exiting a closed throttle corner, less snatch when the fuel injection kicks in. This is especially important if you have a passenger, because they get thrown around much less.
I know I’m going to get flamed for this post. So let me end in saying, when I need to move rapidly, I have no problem snicking it into 3rd or even 2nd and whacking the throttle open. Revs are not my enemy, just revs where they aren’t needed. I don’t need a dyno chart to know where my power is, in fact I discovered there’s a distinct power band from about 5,500 to red line. How did I discover this? Slipping clutch under hard acceleration ( yes, I know it will need changing soon, I have the parts already. )
 
Cheers for that. The link provided on page one is broken. 67lb/ft. of torque at 2,200 rpm. That’s impressive. In fact, the torque curve is pretty flat until about 7,000 rpm. You can definitely feel that broad spread of power. Also the HP line starts at 30. The original VW Beetle had a power curve that PEAKED around 32HP. If a max of 32 HP can move a whole car with 4 people in it, a bike that STARTS at 30HP is certainly capable of trundling along in the lower part of the rev range, with ease.
 
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I did another dyno run 114,000 miles later on the same dyno at the same shop and that thing made a little more power at 158,000 than it did at 44,000. Of course there are variables in dyno tune and atmospheric conditions but even so it surprised me. I expected a little drop in output.
 
that’s amazing. I remember in the 1970s if you were looking for a bike in the classifieds (industry newspaper only) if a bike had more than 15,000 miles it was considered getting close to worn out (BMW excepted). I don’t remember if that was just me and my circle of bikerfriends, or a wider held belief, but the mileage some modern bikes get is fantastic.
 
I hear you and your happiness at sub 2,000 rpm cruise but rev it a little more and the grumbly sound will be less apparent. You won't ever wear it out even wringing it out and it's just as silent wafting along at 2500 or 2800 rpm as it is at 2000.
 
Just curious where you are in the rpm range / load / incline or flat / speed when you're not getting any roll on, if dropping a gear changes anything? I wonder if it's lean, like vacuum leaks or too much PCV air, and your ECM is just able to make up for it. Does it go away a bit at least at 4,000 rpm?
 
I also had some noise on my 152000km 07 St1300. Did a synchronisation on the starter valves. A major difference. I also planned to do the balance shaft.
 
bstig60 said:
They are the throttle bodies (there is one for each cylinder), and like carbs, they need to be synced from time to time. Why don't you try contacting Igofar about your engine noise?
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Oh, so why not just say “throttle bodies”? As far as I can see the butterfly valves in the throttle bodies work all the time and not just at start up or to aid start up; that’s where I was getting confused. Anyway, I’ve had the air box off this thing twice in my brief ownership, once to adjust the cold idle speed ( it would idle way too fast, and take way too long to calm down, meaning snicking it’s into first was accompanied by tremendous knashings from the gearbox) (and no, the rumble was there from my test ride before buying it.).And once to try and trace an electrical short. I did closely observe the butterflies, and the gap when closed was equal to the naked eye. I don’t think I used a feeler gauge and I know I didn’t put my vacuum gauge into use.
how does one contact a member of the forum?
 
The throttle blades are fixed together and not adjustable like they are on carburetors. They should all look identical. The idle air is controlled by starter valves. Balancing the airflow to the throttle bodies using these starter valves is, in effect, balancing the throttle bodies... same thing. After balancing the throttle bodies at idle, you can crack the throttle a bit to take it off idle and see an imbalance in the throttle bodies. For this reason, I find it hard to believe that balancing the starter valves has much effect on performance above idle. I wish that there was still an adjustment to balance or sync the throttle blades, but i guess if it were capable of making an improvement, Honda would have done it.
 
I can't speak to why the Japanese call things what they do! I went back and read the whole thread and I can't find anywhere you described the noise you mentioned. Am I missing something? Adding power at low rpm is going to cause a spark knock. Adding power at most any rpm will get a good growl out of the engine and that is normal. When I first got mine, I learned quickly that you don't try to add power below 2000 rpm.
 
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