Eliminate the rev limiter?

[Old Can Ride]

When me and my ex split she ended up with it. She sold it to get new boobs.

Know a old boy here in Houston who had about the same ex problem, except he wrote a song about it. So, we dedicate this song to "Frozenpoet".

[video=youtube;jt-DXiZHQqM]http://www.youtube.com/watch?v=jt-DXiZHQqM[/video]

 

[silverhound]

When me and my ex split she ended up with it. She sold it to get new boobs.

Well that's just wrong. Between the Vstar and the ex that's two sets of jugs you didn't get to enjoy.

 

[frozenpoet]

Well that's just wrong. Between the Vstar and the ex that's two sets of jugs you didn't get to enjoy.

O I made sure I got to enjoy them at least once.

 

[Mojave]

There are plenty of technical articles on the 700/750 engine that explain how the mission brief of maximum economy from given displacement was achieved

Right - marketing.. I've been reading motorcycle hype for 45 years, it's written for a purpose.

You are correct. With undersquare (long stroke, torquey) engines, the long stroke means high piston velocity.

Show where the velocity of this piston would be too high given it's stroke and a little more RPM. I don't think you can. There are lots of big short stroke engines around where the stroke is about the same that have redlines way higher.

Our rockers are cast aluminum (instead of machined billet or forged). They don't even have the cast flashing machined off. Our valve springs are small and low tension. At high RPMs, this will let the valves float and lead to misfiring, burnt valves and seats, and possibly contact between the valves and pistons.

Right - cheap chintzy components, great. Actually I think, and this is just my opinion here, I bet it's not that bad and this engine has more capacity to rev.

Kind of like comparing a 5.9 liter Cummins to a 5.9 liter V8.

Talking motorcycles here - trucks are different. I don't think this analogy makes much sense.

I think Honda tried something different and got some things right but botched the engine - my opinion. The change to 750 is a half measure of correction.

If the bike suits your riding style or commuting purpose, great. Honda aimed for a segment of the riding population and maybe hit it. I'm not in that segment. I like most of the other NCX qualities and, naturally enough I think, yearn to (mostly) correct the main deficiency. 5 or 10 more mpg means nothing to me. In my riding I pretty much want to pass at will on short visibility mountain roads, the NCX doesn't allow that. Most bikes outside of cruisers and beginner bikes do. Being stuck behind a truck or RV for miles is not defensive riding. I took a chance with the NC and it's not working out. Most of the alternatives have their drawbacks which the NC covers pretty well. For example, a 955 Tiger or 1050 Tiger would definitely be more of a handful in the dirt. I tried the R1150GS and that bike does what I need on the road but is a huge top heavy disaster offroad. Ultimately, I'm not emotionally bought into this bike, I don't have to defend my decision to buy it, or it. Many times in the past I've purchased bikes that didn't work out - I just sell them and move on to something else. I will miss the frunk.

 

[670cc]

The 700X horsepower peak is at 6140 RPM per CW dyno chart. Power is already falling off at the redline. If the NC doesn't have the power to pass a slow vehicle with the stock rev limit, it simply doesn't have the power.

Time to purchase a different motorcycle.

 

[Mojave]

True, and I will, but I'll take my time. My issue with it isn't dire, just an irritation, and not worth arguing about! In rock climbing it's what we call a "geo-fantasy", the rock we are peering at thinking to developed would be nicer if it were: higher, smoother, rougher, steeper, less steep, facing some other direction, didn't have ants/poison oak/road noise/swooping hawks, etc etc. Can't change it, so just have fun.

I'm taking it on a ride up to the Bay Area in the next couple weeks through the lovely roads in the hills east of 101, then back down the Pacific Coast highway, it should do great.

 

[SergeantChuck]

I've had a conversation with my wife about this very topic but it went a different direction. I've actually told her I am glad this bike doesn't have any of the attributes of my former CBRs. Don't get me wrong. I miss the power but it is a good thing I don't have it.

I was reminded why this bike is good for me a few days ago when riding home. A couple of knuckleheads on sports bikes came up behind me moving at about 90mph on a two lane road. I thought surely they would slow down since there was oncoming traffic but they didn't. They spilt the traffic down the center line.

Anyway, I didn't do things that stupid but close. The fact that this bike doesn't allow me to do things like that is good. Low revs is not a concern to me. I personally do not think the low rev motor or lack of power makes this bike unsafe in situations where you need something extra in heavy traffic. I drive around Little Rock, AR everyday. Lots of traffic and lots of terrible drivers. I feel completely comfortable in heavy traffic and have never once though that I couldn't power out of a situation if needed. At slow speeds this bike actually accelerates fairly well. The high speed acceleration is where I think the bike is lacking.

I'm glad this bike is the way it is or I'd be acting a fool and getting myself killed. Just my opinion.

 

[Mojave]

I'm in the same camp. I've had lots of too powerful bikes that I simply couldn't ride the engine to the upmost. A Ducati S4R was the worst - the front end would come up at 60mph! I'd nose around on sandy mountain roads barely cracking the throttle past the infamous Ducati surging.

I'm really pretty happy on any bike, however small. My beef is with cars I come up on, are clearly going a slower pace than me, but then speed up to block a pass. I used to ride a DR650 around, this didn't happen much, but once in a while... On a faster bike there simply isn't an issue, it's trivial to pass safely any (typical) car. I don't race WRX's, Corvettes, etc, and I don't split traffic on a two lane highway either, LOL! but I do cross the double yellow all the time. California a while back removed 90% of the passing sections on mountain roads. For cars this made sense as the straights were clearly not long enough unless the passing driver really nailed it and the driver being past cooperated. Human nature being what it is this didn't always happen.

Anyway, I have a tendency to argue technical issues, which is a little obnoxious (I'm told). Cheers, have a good ride!

 

[bigjeff]

Hmmmm - I have multiple bikes and have had many others over the last 40 years so I know what power feels like. Curiously, I have found the NCX has plenty of power for everyday riding at sane speeds.

0-80 the nc is quick enough to dispatch MOST cars with ease - over 80 - it runs out of breath. The bike WILL do the ton with ease - just takes a bit of a wait to get there.

Best way to make power for accleration past cars at speed is to short shift and ride the torque. More RPM will do you no good on this engine - the HP drops off at a little over 6k anyways.

 

[davidc83]

I with Pegasus on this, only I have only 43 years experience. Once in a while an extra 1000rpm would be nice. No, it probably won't be the peak power but it provides some flexibility for certain situations.

Not picking on you Dave on this rant - rev limiters are there to prevent engine damage. But to work that issue - why would this particular engine be unusually susceptible to that? Any 650 modern twin is redlined much higher. Did Honda use such a junk design that the redline must be kept really low? I think/hope that is a rhetorical question. Piston speed isn't the issue. Hydraulic valves aren't the issue. Is there a mechanical issue like a really chintzy crankshaft design? I hope no. Would the engine run out of breath at 7000+, probably. Single throttle body, crazy exhaust port and header, long stroke, all conspire against good highspeed breathing. But most bikes have a redline that provides significant overrun past where the engine is making peak power. Why not just provide the overrun?



If you believe the marketing. I ride my NCX std like any other bike I've had (75-80mph cruise, brisk acceleration) and it's getting 55mpg on Kali winter gas. The Sprint 955i I had got 53 and I was *probably* going faster on it. So is Honda being an institutional "nanny"? Limit the power available and you shape behavior?

There are qualities to the NCX I like - comfortable, good offroad, light natural handling. The power is adequate for the most part, but for some situations it falls short. Those situations are safety related - with enough power you can do certain things safely, if you know what I mean. When I ride I don't sit behind motorhomes and cars on mountain roads - I pass them. With the NCX that's problematic. With a little overrun it would be less so.

I had a bmw g650gs and even though the redline was 900 rpms higher (7400rpm) it ran 1000 rpms higher in every gear above 2nd and any comparible speed. In 6th gear on the NC700x, 60mph is 3000-3100rpm; on the bmw g650gs, in 5th gear (no 6th gear), at 60mph, it was running 4000rpms: same comparisons at 70mph, 80mph, etc....
I have yet to hit a limiter after 7000+ miles on the bike, but then I don't shift by the tach (I listen to the bike-it tells me when to shift) and if I need more power, I downshift to 5th or 4th-I was doing 68mph in 4th gear the other day and didn't hit the limiter, upshifted to 5th and got to 80mph lickity split without hitting the limiter; but then I have never owned a 'permformance' bike, and I am used to the low rpms.

 

[davidc83]

Hmmmm - I have multiple bikes and have had many others over the last 40 years so I know what power feels like. Curiously, I have found the NCX has plenty of power for everyday riding at sane speeds.

0-80 the nc is quick enough to dispatch MOST cars with ease - over 80 - it runs out of breath. The bike WILL do the ton with ease - just takes a bit of a wait to get there.

Best way to make power for accleration past cars at speed is to short shift and ride the torque. More RPM will do you no good on this engine - the HP drops off at a little over 6k anyways.

I agree with your comments, and for those riders who think speed gets you out of trouble-NOT! speed will get you into trouble. There is no production bike which can go from 0-60mph in a shorter distance than 60-0mph ( and any other comparable speeds)(even the bmw s1000rr has a shorter braking distance than accelerating distance). Gravity and friction are the two culprits for the longer acceleration distance while gravity and friction helps the braking distance. Most of the time, you can slow down and get out of trouble easier/quicker/safer than trying to twist the throttle...

 

[MAJikMARCer]

I get the point of this thread, but to me this makes me think of those guys who tune Honda Civics. I'm sure it's fun. They are cheap after all. But you are only going to get so much out of that little engine and in the end shorten it's life. I'd say if you want power buy the bike with the power. If you like to tweak and tune and engine life isn't a concern, what the hell.

If it's just a little ranting/buyers remorse, I get that too.

 

[Mike Cash]

I only wish they had made the rev limiter merely limit the revs instead of suddenly cutting out the power.

 

[L.B.S.]

I only wish they had made the rev limiter merely limit the revs instead of suddenly cutting out the power.

Apparently they did this with the 750, I sure do wonder if it would be a possibility to do some kind of firmware update/transfer to the 700's ecu?

 

[IronButt84]

I agree with your comments, and for those riders who think speed gets you out of trouble-NOT! speed will get you into trouble. There is no production bike which can go from 0-60mph in a shorter distance than 60-0mph ( and any other comparable speeds)(even the bmw s1000rr has a shorter braking distance than accelerating distance). Gravity and friction are the two culprits for the longer acceleration distance while gravity and friction helps the braking distance. Most of the time, you can slow down and get out of trouble easier/quicker/safer than trying to twist the throttle...

I have to disagree.......I've had plenty of incidents where my throttle saved the day.

 

[davidc83]

I have to disagree.......I've had plenty of incidents where my throttle saved the day.

Exceptions to every rule; just like people who complain about drivers driving too slow when it snows; most of the people who loose control on snow probably wasn't driving too slow.....

 

[Mi_ka]

In the "other forum" where we discussed the matter, a properly educated and experienced in the field guy pointed out using engine theory as his basis that this engine is designed to breath in a fuel efficiency extravagant way on the low-mid rpm spectrum keeping intake gasses' speed high at low-mid rpm giving away high rpm intake pumping ability (low-mid rpm in comparison to what is usual in the motorcycle world - cars have always been designed more or less this way since they need much heftier torque output dow low due to their much higher mass per engine output in comparison to bikes - it would be no fun to have to race the engine just to start moving your car in traffic, mpg problems aside).
Anyone interested can find even more elaboration here besides the link Ste7ios posted back on page 1.
We speculated that since this engine cannot breath properly in high rpm by design scope, they have also elected to go by soft valve return springs and narrow rod and? crankshaft bearings to cut down mechanical and oleodynamic friction losses in order to achieve their impressive consumption goal.
So no, it seems that the rev limiter is not there by some Honda's marketing caprice but for a reason, even more due to the easy and peaceful way this engine could go deep in the red tachometer zone running like a swiss clock until a very possible terminating ka-pow.

Having said the above, the similarly design minded Honda car engines seem to cope very well in out-of-mind ricer modifications but I see no reason in messing such a fine design in that way in order to achieve elusive power outputs even though I can really see canyon carving benefits in an extended redline by 1K rpm even at the cost of much lower torque (power) output as rpm rise above 6500
BUT
if this means an extensive redesign to support higher part loads compromising mpg then it is no good by my current standards and needs unless I could live with very probable lower reliability that simply moving the limiter higher in the range by ECU tweaking keeping all else as is in the NC engine would provide.
And by "live" I mean survive since a catastrophic mid-corner engine blowout could mean so much more than a ricer-car blowout since consequences on a bike are usually much more serious for the guy on it than for a car's driver.
Bikes need reliable engines much more than cars due to live-or-die obvious reasons.

 

[mtbmike]

I'm in the same camp. I've had lots of too powerful bikes that I simply couldn't ride the engine to the upmost. A Ducati S4R was the worst - the front end would come up at 60mph! I'd nose around on sandy mountain roads barely cracking the throttle past the infamous Ducati surging.

I'm really pretty happy on any bike, however small. My beef is with cars I come up on, are clearly going a slower pace than me, but then speed up to block a pass. I used to ride a DR650 around, this didn't happen much, but once in a while... On a faster bike there simply isn't an issue, it's trivial to pass safely any (typical) car. I don't race WRX's, Corvettes, etc, and I don't split traffic on a two lane highway either, LOL! but I do cross the double yellow all the time. California a while back removed 90% of the passing sections on mountain roads. For cars this made sense as the straights were clearly not long enough unless the passing driver really nailed it and the driver being past cooperated. Human nature being what it is this didn't always happen.

Anyway, I have a tendency to argue technical issues, which is a little obnoxious (I'm told). Cheers, have a good ride!

I went on a 300 mile road trip with a 2005 bmw gs1200 on Friday and I was in this situation a crap ton of times I had zero problems passing slower cars when needed and hanging with the big gs. Here is a scenario we are riding up on some slower cars that are going about 60 in a 75 we have to get by 3 cars 6th gear going 60 puts me around 3000 plus or minus 100 rpm that means I have 3000 rpm to play with click it down 2 gears and the revs jump to 5000 the nc powers out very nicely and I quick shift to avoid the limiter next thing I know I am right on the bmw 1200 rear tire accelerating at the same exact pace to get by 3 cars with plenty of wiggle room to the limiter because the bikes rpms climb slower the higher the gear this happened several times . You need to lean how to ride the nc in these situations when you do you you will find out it has plenty of passing power when you use the gear box correctly if you are trying to pull cars in 6th gear forget it. My 919 I don't have to think about it don't even have to shift and it pulls like a freight train and I can pass 3 cars in about 4.5 seconds if I click it down a gear or 2 even faster. If this is the performance you want then you need a liter bike because even a 600 super sport wont do that other wise the NC is perfectly capable in. One other thing if the cars decide to speedup they will not be able to hold you off unless they are in a sport car because they will not be able to anticipate quickly enough trust me.

 

[anglachel]

Exceptions to every rule; just like people who complain about drivers driving too slow when it snows; most of the people who loose control on snow probably wasn't driving too slow.....

Good way to tell if they lost control on the snow from driving to slow is to check the rear fenders for black paint to see if I pushed them off the road so I could pass... other indicators are out of state plates (I got stuck behind some one from ny state this winter who had no business being on the road... 5 mph on a straight highway, that had been mostly plowed) and exhaust systems that are dragging on the ground (nothing give me more road rage than a car so poorly maintained that parts are falling off and becoming obstacles for roses behind them.)

Seriously though I've been bicycling far longer then I've been motorcycling, I've always been able to out brake cars, I'd not always been able to get out of their way (which is part of why my bicycle has an air horn on it now).

On the nc I can out brake, out run, and, out handle almost any car I'm likely to see on the road. Being able to get out of the way with the throttle is the only thing I can do on the nc that I couldn't do on the bicycle... and it is wonderful.

I take nothing off the table when it comes to my safety on the bike, brakes, gas, steering, down shifting, ect. If I can physically pull it off and end up better off for it I'm doing it, try to keep it legal to the best of my abilities, but the law takes a back seat to my safety. Every one out there is trying to kill me (it's not paranoia when it is true) and I'd rather have some of the idiots well behind me than serving around in front of, or worse next to, me.

Sent from my SAMSUNG-SGH-I537 using Tapatalk

 

[bigjeff]

I only wish they had made the rev limiter merely limit the revs instead of suddenly cutting out the power.

If you don't short shift you are missing out on the best power production from this engine. This engine is designed to produce torque, not horsepower. The best wave of torque to surf is well below redline. Wringing it's neck for more power will only disappoint.

Try it - you'll like it.