2017 CB1100 EX First Ride Review

[emptysea]

Ecu does fuel and ign curves. As in advance or retard, nothing to do with staggering of the cam timing.


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OK...so first off, thanks. Now, would changing the ignition curves change the engine tone or feel?

Also, and maybe this isn't the place for a discussion on basic mechanics, but how can valve timing be changed if the cam has not changed? (probably a dumb question, sorry)

[VLJ_imp]

Guth, do you think the obvious change in the engine note—not the exhaust volume, but the additional crunchy texture so easily heard in the comparison videos, and felt throughout the bike—can be explained solely by a shorter inlet tract and a smaller exhaust system?

That doesn't sound very plausible to me.

It doesn’t seem plausible that changes to the only 2 places the engine emits noise could change said noise?





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It doesn’t seem plausible that changes to the only 2 places the engine emits noise could change said noise?
No, it doesn't seem plausible that those two changes would create the different type of vibration felt throughout the bike, as well as the noticeably more arrhythmic texture of the sound.

The difference is similar to but nowhere near as pronounced as the difference one hears and feels when switching from an old R1 to a crossplane R1. Shorter inlets and slightly smaller OEM exhaust pipes can't explain such a noticeable change to the basic feel of the bike, never mind the different tone.

[Flytech99_imp]

Ecu does fuel and ign curves. As in advance or retard, nothing to do with staggering of the cam timing.


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OK...so first off, thanks. Now, would changing the ignition curves change the engine tone or feel?

Also, and maybe this isn't the place for a discussion on basic mechanics, but how can valve timing be changed if the cam has not changed? (probably a dumb question, sorry)

OK...so first off, thanks. Now, would changing the ignition curves change the engine tone or feel?

Also, and maybe this isn't the place for a discussion on basic mechanics, but how can valve timing be changed if the cam has not changed? (probably a dumb question, sorry)
Valve timing is 100% controlled by the cam, either by changing the shape of its lobes or its relative angle to the rest of the valve train (variable valve timing).

Ignition timing is purely electronic and can certainly effect the engine's feel in a negative way, especially if not optimized with AFR. Heat and excessive head pressure are also byproducts of aggressive timing which is obviously not wanted with air/oil cooling (and doesn't support the longer valve inspection intervals on the '17 models). I don't see how Honda could've only used ignition timing to get a FELT effect without changing a lot of other things to compensate (to include power output).

[Guth_imp]

Thanks, PowerDubs... Questions from a guy who performed his last timing adjustment on a 1970 Plymouth in his Automotives class in 1978:

ecu tuning would not change the timing, correct? that basically controls the fuel mix, right? Or does the ecu control ignition as well?

The best way to know for sure would be to reference the factory service manual. These specifications appear in the manual.

Exactly my point...just much better stated.

Exactly my point...just much better stated.
Oh jeez, I was out for a while. I must have missed more of this thread than I realized, lol.

[Flytech99_imp]

Excerpt from from interview with engineer designing first gen CB1100 engine form Honda Worldwide site:

Sekiya:
On the hardware side, phased valve timing gives the engine its characteristic feel around the 3,000 rpm range. How did you create the engine's personality?

Minami:
Basically, straight-four engines run smooth as long as all four pistons move the same way. My initial thoughts were, to give the engine a deep rumble, we'd have to change the movement a bit.
We ended up shifting the valve timing of cylinders 1 and 2, compared to cylinders 3 and 4, and by continuing to change the gap, found the right combustion out-of-sync feel.

Sekiya:
Valve timing is usually changed or made variable to increase output, but your aim was completely different. Maybe the exact opposite of conventional wisdom.

Minami:
Precisely. We took the opposite approach to conventional thinking, so we weren't sure if it would work.

If the cam is the same across the board, then this must have went full circle and surfaced again when the '17 was introduced??? Regardless, I think it's pretty obvious this is a key reason why the CB's power output remains modest... Honda was clearly more concerned with feel and sound than HP (which is OK-fine by me!)

[Guth_imp]

I remember back when the CB1100 had yet to be released here in the States. Someone wrote the the bike contained a single 36mm throttle body and then this was repeated numerous times until people figured out that wasn't the case. The only sure way to know these things would be to reference the service manual.

I have no doubt that there is some placebo effect involved. That's honestly one of the best things about buying any new vehicle — it's just such an awesome feeling. But that's not to imply that changes haven't been made. I have no doubt that there are a number of differences between my 2013 model and VLJ's 2017 model. As to what those specific changes are, I'm personally not too concerned about it but I would like to make sure that we're keeping our facts straight as much as possible (or at least get them straightened out as soon as possible) around here if for no other reason than for future reference. That is part of the value this forum offers after all.

[VLJ_imp]

If it turns out that the reports were wrong, and the only changes made to the '17 were in fact the shorter inlet tracts and exhaust system, and those two small changes somehow made my bike feel and sound that much different from Eric's '14, well, who cares how Honda did it, right? All that matters is that they did it, and one blip of my throttle was all it took for me to realize that the '17 not only sounded but also felt very different from the '14, and quite a bit cooler.

As for the possibility of erroneous info popping up in various reviews, sure, it's entirely possible, but the reviewer in the link I provided who stated that the '17's combustion chamber and fins were altered to help Honda meet the new Euro 4 requirements was mighty specific with those particular bits of reportage. Either someone at Honda fed him that info or he made it up out of thin air, and the latter seems wildly unlikely.

[alprider]

i can 100% confirm bcos i have a 14 and 17 model side by side: its a different feeling......and both are fine in her ways.....amen.....

[Guth_imp]

If it turns out that the reports were wrong, and the only changes made to the '17 were in fact the shorter inlet tracts and exhaust system, and those two small changes somehow made my bike feel and sound that much different from Eric's '14, well, who cares how Honda did it, right? All that matters is that they did it, and one blip of my throttle was all it took for me to realize that the '17 not only sounded but also felt very different from the '14, and quite a bit cooler.

As for the possibility of erroneous info popping up in various reviews, sure, it's entirely possible, but the reviewer in the link I provided who stated that the '17's combustion chamber and fins were altered to help Honda meet the new Euro 4 requirements was mighty specific with those particular bits of reportage. Either someone at Honda fed him that info or he made it up out of thin air, and the latter seems wildly unlikely.

I get it, my Staintune has the [url=http://cb1100forum.com/forum/showthread.php?tid=12089&pid=194255#pid194255]same effect. Some have reported around here that based on what they read the 2017 has more torque and power down low and has less up top than the previous models. That didn't make sense to me (I thought Honda might have headed in the opposite direction), but maybe there's something to that after all. Like I've said from very early on, these bikes are mostly for show (I bought mine primarily for the looks, and I'm not sure Honda would still be selling them if they weren't so beautiful to look at). The fact that they are actually great motorcycles with a little bit of git up 'n go is just the icing on the cake for me.

[itstuantran_imp]

This is well described about how the RS sounds "It sounds louder, deeper, and meaner, and you can feel the individual pulses more distinctly. It's almost like a V4 now. Call it halfway between a normal I4 and a V4."

At 2nd gear and rev it up to 3500 - 4000rpm, distinct sound coming out like something in between of V4 and I4

Guth, I'm no engineer, so I couldn't tell you how they altered the timing, but in their press releases and interviews Honda's engineers boasted that the timing of cylinders one and two were revised for the '17 motor in order to create a lumpier feel at low RPM, along with a more characterful tone. This new tone is clearly heard in any of the side-by-side comparison demonstrations, and with the revised, shorter exhaust system the sound is definitely deeper and snarlier.

My bike absolutely sounds and feels different from Eric's '14 Standard. It sounds louder, deeper, and meaner, and you can feel the individual pulses more distinctly. It's almost like a V4 now. Call it halfway between a normal I4 and a V4.

I don't know what the goal (or net result) was in shortening the inlet tracts, but that was the other stated change to the '17 motor.