Jump to content
Mike5100

rapid bike easy

Recommended Posts

Mike5100

The Africa Twin is snatchier than any of my previous NC's at low revs, and this device claims to cure it with a plug and play module that takes 15 minutes to fit.  I seem to remember knowledgeable people like Mika and Embee explaining why these devices that modify the lambda sensor don't work (or rather stop working after a while).  But I've done a search and can't find their explanations.  If anyone thinks the Rapid Bike Easy might work, I'd appreciate knowing as it's not too expensive 

http://www.dimsport.it/en/rapidbike/easy/

Thanks

Mike

 

Share this post


Link to post
Tex

I think these devices work by ‘fooling’ the ECU into thinking it’s colder than it is to make it deliver more fuel. Unless you have access to a dyno and can check power and air/fuel ratios under load how do you even know it needs to be richer?

 

There’s a common misconception that current emissions regulations have all engines running leaner than is desirable and an ‘across the board’ enrichment is required. I’m certainly not convinced by the argument. Factory designers and engineers are pretty sharp and do a damn good job. Euro 4 compliant bikes are some of the nicest I have experienced.

 

 I would start with a dyno run (with a truly skilled operator) before deciding anything. If changes to the fuelling are required then a power commander (dialled in by an expert) is the answer.

 

Good luck.

  • Like 1

Share this post


Link to post
chrisl01

I've tried these devices on 2 bike I owned that had horrid low speed snatch and surge and they just did not work.

The Aprilia Strada I had was so bad I sold as it, after spending over £200 on Lambda modifier and power commander..

I test road a Ducati Scrambler last year and it is terrible at low speed (in my opinion dangerous in town traffic round a roundabout for example) and the Ducat forum is full of guys trying to solve it, G2 throttle tube etc. the 2017 Desert sledge is good by all accounts and has the same engine but a modified ECU I was told.

When I test road my 750X I could not believe how smooth it was at low speed and think it one of its best features but never gets mentioned.

  • Like 1

Share this post


Link to post
Mike5100

Yes the 750 is smooth at low speed despite being leaned off for low rev emissions, but I think the lumpiness is also reduced because it's a relatively low powered bike and any power on/off pulses are likely to be smoothed out better than with a bigger engines bike like the Africa Twin

Simon - if you follow that link then elsewhere on the site they seem to be saying that they are only fooling the ECU in the rev range that Euro4 is causing problems.  Having said that they have put a IMHO stupid graph on the Rapid Bike Easy page which seems to plot a/f ratio against km/hour rather than rpm.

Others say they work and I would like to smooth out the round town snatchiness completely - it's not bad but mildly irritating.  Would a different air filter help does anyone think?

Mike

Share this post


Link to post
suffolk58

If it does work, I'd be keen to know.

Last summer I road tested the Suzuki Vstrom 1000. The price was good and the bike felt good to sit on.

Riding it was a real disappointment, as the fueling was awful. Like a puppy on lead for the first time. Trying to keep the ride smooth was almost impossible, and I ended up disliking the bike. Which was a shame, as otherwise it was a great bike.

Share this post


Link to post
embee

They are not running lean, they'll all be running stoichiometric (lambda=1) on feedback at low speed/light load conditions. The add-on device tells the ECU it's effectively colder so makes it run richer as a base setting so the engine management is always trying to lean it off towards lambda=1 rather than swinging rich/lean.

 

I haven't looked again, but I remember commenting last time that the one in question then was a bit better than some in that it didn't simply apply a fixed resistor alteration to the temp sensor, but used a second thermistor to give a variable effect. I can't comment whether it would help with driveability of any particular bike.

 

The most common cause for poor driveability is far too aggressive throttle progression in my opinion. Just the smallest change in your right hand position gives a far too big a change in throttle angle when just off closed throttle. This is (IMO) an undesirable design feature used to make the bike feel much more responsive and so more "powerful". It also unfortunately makes it very snatchy and jerky when you're on bumpier roads due to tiny movements of your hand making relatively big changes to engine output. A simple part-fix is to use a "slower" throttle tube (smaller diameter cable pulley at your hand). The better solution is a re-profiled throttle body cable cam with a slower initial progression, but no-one makes these as far as I'm aware (too much complexity). They are not normally circular, the shape of the snail gives the progression.  It wouldn't affect the overall fuelling since it simply alters the progression relation between your hand and the throttle spindle, the airflow vs spindle angle relationship stays exactly the same.

An example showing the progression of a throttle cable cam.

20170109_121339resize.jpg.524cf01b215b9113ecb878a55d050640.jpg

 

  • Like 1
  • Thanks 2

Share this post


Link to post
wendeg
2 hours ago, embee said:

They are not running lean, they'll all be running stoichiometric (lambda=1) on feedback at low speed/light load conditions. The add-on device tells the ECU it's effectively colder so makes it run richer as a base setting so the engine management is always trying to lean it off towards lambda=1 rather than swinging rich/lean.

 

I haven't looked again, but I remember commenting last time that the one in question then was a bit better than some in that it didn't simply apply a fixed resistor alteration to the temp sensor, but used a second thermistor to give a variable effect. I can't comment whether it would help with driveability of any particular bike.

 

The most common cause for poor driveability is far too aggressive throttle progression in my opinion. Just the smallest change in your right hand position gives a far too big a change in throttle angle when just off closed throttle. This is (IMO) an undesirable design feature used to make the bike feel much more responsive and so more "powerful". It also unfortunately makes it very snatchy and jerky when you're on bumpier roads due to tiny movements of your hand making relatively big changes to engine output. A simple part-fix is to use a "slower" throttle tube (smaller diameter cable pulley at your hand). The better solution is a re-profiled throttle body cable cam with a slower initial progression, but no-one makes these as far as I'm aware (too much complexity). They are not normally circular, the shape of the snail gives the progression.  It wouldn't affect the overall fuelling since it simply alters the progression relation between your hand and the throttle spindle, the airflow vs spindle angle relationship stays exactly the same.

An example showing the progression of a throttle cable cam.

20170109_121339resize.jpg.524cf01b215b9113ecb878a55d050640.jpg

 

G2 Ergonomics make Throttle Tamers https://www.g2ergo.com/

  • Like 1

Share this post


Link to post
trisaki
3 hours ago, suffolk58 said:

If it does work, I'd be keen to know.

Last summer I road tested the Suzuki Vstrom 1000. The price was good and the bike felt good to sit on.

Riding it was a real disappointment, as the fueling was awful. Like a puppy on lead for the first time. Trying to keep the ride smooth was almost impossible, and I ended up disliking the bike. Which was a shame, as otherwise it was a great bike.

Mate who owns the latest vstrom 1000 reckons it's soo much better  now compared with earlier version  apart from the thin paint etc 

  • Thanks 1

Share this post


Link to post
trisaki

Fitted a plug in box to my very snatchy  guzzi griso  as it was horrible  to ride around town after I checked throttle body balance etc got to admit  it  has made it an awful  lot less snatchy  not perfect but certainly  a lot easier to ride slowly  /  been  told I can get my ecu reprogrammed  if I need it any better  

Edited by trisaki

Share this post


Link to post
embee
1 hour ago, wendeg said:

G2 Ergonomics make Throttle Tamers https://www.g2ergo.com/

Hadn't seen anyone making anything before. Yes, the street tamer version would do the trick, it's putting the progression into the throttle tube (twistgrip) end (which is normally just circular) rather than doing it at the throttle body end. Ought to be an easy practical mod, if a little pricey, but at least it's going to have a real effect.

Share this post


Link to post
Mike5100
4 hours ago, embee said:

They are not running lean, they'll all be running stoichiometric (lambda=1) on feedback at low speed/light load conditions. The add-on device tells the ECU it's effectively colder so makes it run richer as a base setting so the engine management is always trying to lean it off towards lambda=1 rather than swinging rich/lean.

 

I haven't looked again, but I remember commenting last time that the one in question then was a bit better than some in that it didn't simply apply a fixed resistor alteration to the temp sensor, but used a second thermistor to give a variable effect. I can't comment whether it would help with driveability of any particular bike.

 

The most common cause for poor driveability is far too aggressive throttle progression in my opinion. Just the smallest change in your right hand position gives a far too big a change in throttle angle when just off closed throttle. This is (IMO) an undesirable design feature used to make the bike feel much more responsive and so more "powerful". It also unfortunately makes it very snatchy and jerky when you're on bumpier roads due to tiny movements of your hand making relatively big changes to engine output. A simple part-fix is to use a "slower" throttle tube (smaller diameter cable pulley at your hand). The better solution is a re-profiled throttle body cable cam with a slower initial progression, but no-one makes these as far as I'm aware (too much complexity). They are not normally circular, the shape of the snail gives the progression.  It wouldn't affect the overall fuelling since it simply alters the progression relation between your hand and the throttle spindle, the airflow vs spindle angle relationship stays exactly the same.

An example showing the progression of a throttle cable cam.

20170109_121339resize.jpg.524cf01b215b9113ecb878a55d050640.jpg

 

I can vouch for this explanation Murray but ironically because of the opposite effect.  i have a Kaoke cruise control and if I have it set for high friction on the motorway and forget to turn it back to free turning, I can find myself nearly falling off the bike at the first corner.  This is because the very sensitive throttle control that my brain has worked out is necessary for smooth riding, goes all to pot if the kaoke is wound on.  In fact if the bike wasn't a DCT I am sure I would have stalled it on several occaions because of this effect, then I would have been on the floor.

If you have time could you take a closer look at the rapidbikeeasy at http://www.dimsport.it/en/rapidbike/easy/http://www.dimsport.it/en/rapidbike/easy/ and comment on whether you think it is one of the cleverer ones that might work.  

I would use the cam throttle thing but I have had heated grips fitted and I'd rather not sacrifice them.

Thanks

Mike

  • Like 1

Share this post


Link to post
embee
1 hour ago, Mike5100 said:

...

If you have time could you take a closer look at the rapidbikeeasy at http://www.dimsport.it/en/rapidbike/easy/http://www.dimsport.it/en/rapidbike/easy/ and comment on whether you think it is one of the cleverer ones that might work.  

.......

Ah, OK, that's a different approach. It's taking the lambda sensor output and modifying it into something else. The other ones I've seen have been fiddling with the temperature sensor values. Interesting they say "... placing the lambda sensor value in the ideal range between 13.5 and 14.5."

Well I'm not sure on what basis they mean this is the "ideal range". It certainly isn't the ideal range for emissions nor for economy. HC and CO will be sky high, but you may not be concerned about that. On the plus side NOx will be low. It does give probably the maximum brake output for a given airflow (but not best economy), which is why they say more speed for a set throttle position, but if you're at part throttle this is pretty irrelevant (just open the throttle a bit more), and once above a certain throttle opening the factory ECU will go open loop and should run about 13.5 A/F for max output at full throttle anyway. Conveniently this part will be at a higher speed than their graph goes to.

Not sure what you are meaning by "might work". It looks like it's engineered to make the engine run richer when on closed loop. What do you want it to achieve? Will it solve any driveability issues? It depends what's causing the driveability issues. I have no idea whether it will do what anyone wants it to do, but it should make it run generally richer according to their description.

  • Like 1

Share this post


Link to post
Tex
6 hours ago, embee said:

Not sure what you are meaning by "might work". It looks like it's engineered to make the engine run richer when on closed loop. What do you want it to achieve? Will it solve any driveability issues? It depends what's causing the driveability issues. I have no idea whether it will do what anyone wants it to do, but it should make it run generally richer according to their description.

 

Exactly. All these devices work on the assumption that the fuel mixture is ‘too weak’ and a good gobfull of extra fuel will solve everything. I’m not convinced that the Honda Motor Corporation doesn’t know better than Bert Bloggs in his garden shed. :) 

  • Like 1

Share this post


Link to post
Mike5100

But surely the whole point of these things (and we've all had numerous discussions on this subject) is that in order for a manufacturer to get a bike through various Euro  regulations they have to lean it more than is ideal in the low rev range, and this makes most bikes lumpy and snatchy round town.  Richening up the mixture in that low rev range surely puts it back to where the engine would like to be and isn't illegal yet.  It worked wonders for me on a Kawasaki Versys with a power commander.  I never felt the need on the NC for reasons I mention above - Honda have done a good job within the parameters they have to work, and the low power engine and the DCT help smooth out the roughness.  Triumph by the way seem to have got low rpm fuelling issues well sorted - maybe it's in the nature of 3 cylinder bikes, but all the triumphs I have ridden in recent years have been excellent when dawdling around.

Mike

Share this post


Link to post
Tex

It rather sounds as though you’ve already made your mind up then, Mike. In which case, go for it and report back here with your findings. My current Triumph twin is, indeed, exemplary at dawdling speeds. But that has a single throttle body (like the NC has). I have heard murmurs that the 1200 Triumph twins (which use twin bodies) can be snatchy. I’m assuming the Affy Twin also has twin throttles? Could account for the difference.

 

Keep us posted, please.

Share this post


Link to post
embee

Again, sorry to sound like a broken record, but they don't run lean. They run at or cycling close to stoichiometric, not lean. If you run it richer than stoichiometric what it can do is mask poor transient calibrations which might result in undesirable lean excursions. If it goes too rich it can get "soggy" but will run OK up to the point where it is simply too rich, the limit is somewhere round 9:1AFR usually. If it goes lean it will get "fluffy" and hesitant, up to the lean limit which is typically around 18:1AFR for practical purposes. The combustion stability gets worse in both directions but the lean direction is usually more noticeable and less forgiving of transients.

 

I suspect the issues often encountered are a combination of big throttles and aggressive progression combined with relatively basic functions to cope with detecting transient air flow. Cars almost always use mass air flow meters combined with throttle position sensors. These allow a calibration which detects when the throttle moves and also when the air flow changes and can thus be tailored to deliver fuel when it is needed. If you use throttle position and density (like most bikes I believe) it is more difficult to get the delivery at exactly the right time (density lags behind flow, you have to use the TPI to "predict" the air arriving at the cylinders) so potentially undesirable A/F excursions away from where you want it. The bigger the throttles the more abrupt the air flow change with very small movements, making TPI calibrations very touchy. As Simon says, a single throttle supplying multi-cylinders makes a throttle angle/density system a lot easier to calibrate effectively.

Tricking it into running richer than calibrated will quite possibly mask such shortcomings, but it will be running rich essentially all the time. Potentially this could cause carbon build up on the lambda sensor and catalyst monolith over time if it never gets any free oxygen to burn it off. It may well get it to run more acceptably for you.

 

At present in the UK as far as I know it is not actually illegal per se to alter a vehicle in such a way, but it certainly won't meet emission regulations if that bothers you.

  • Like 2

Share this post


Link to post
pjm

Funny you should mention the Kaoko cruise control. On my ride up to the peaks I used it a fair bit and like you had left it on but only slightly. I found it dramatically smoothed out the low speed 'snatchiness' but after a while my wrist was beginning to ache from the extra effort. In fact I recall mentioning it to CFB as we chatted away. It would be interesting to experiment to find the ideal compromise. Certainly a darn sight cheaper and simpler than some of the more complex alternatives.

  • Like 1

Share this post


Link to post
Graham NZ

I'd rate the low speed/low throttle response of my NC very good, especially in MT.  I've had a cammed throttle on an earlier bike and it was a gem.  My Guzzi Breva V1100 ran better when cold with the stepper motor by-passed using the manual valve I fitted to the vacuum line to it.  One throttle is much better than more for slow speed response.  Guzzi got that right with the current 750 bikes.  The Norton Mercury I owned had a single carb and was much sweeter that the 650SS with it's always-needing-balancing twin carbs.  I was continually balancing the the throttles and zeroing the TPS on my two 1100 Guzzis.  That the NC has one throttle body is an example of intelligent design operating because these bikes are intended for practical use rather than as sport bikes.

  • Like 1

Share this post


Link to post
rainmaker

My NC700 was snatchy in low revs and my Africa Twin is pretty much the same. One way to deal with that I found is just keep the revs higher. For DCT that means one of the sport modes.

 

I looked at Rapid Bike product before, mostly just curiosity as I am not convinced they actually cure the issue. One note to point out is that somewhere I read specifically for Africa Twin the install is not 15 minutes and needs quite a bit disassembling. 

Share this post


Link to post
Chris750

Not sure what's happening with these "snatchy" bike's.  I've owned 3 NC's all DCT and the fuellng has been spot on, likewise the CRF1000.

Share this post


Link to post
Graham NZ

Doing a DCT reset did seem to improve pickup off a closed throttle despite it being a clutch-operation-only procedure.  I can 'walk my bike' into the garage in any mode through a very narrow gap with all the throttle/clutch finesse needed.

Share this post


Link to post
Mike5100

yes I agree all the NC's I had were very well mannered at low revs - the AT less so.  And when the NC dct did get a bit crotchetty, the DCT reset procedure gave a very noticeable improvement.  Again not so with the once I have tried the reset with thee Africa Twin.

Mike

Share this post


Link to post
SteveThackery
On 12/01/2018 at 14:12, embee said:

Again, sorry to sound like a broken record, but they don't run lean. They run at or cycling close to stoichiometric, not lean.

 

Absolutely spot on, and it's a point that some people seem unable to take on board.

 

However, a point of order: running stoichiometric might still be leaner than "ideal" or "correct" for a particular engine speed / throttle position.  One reason is that most motorcycle engines have far "wilder" cam timings than car engines, which makes them inherently less co-operative at low speeds and loads and more needy of a rich mixture.

 

It is interesting to note that most modern motorcycles don't idle at stoichiometric: in fact, the NC is one of the few that do and Honda regard it as an achievement worth congratulating themselves over (see Honda's R&D pages - I've temporarily lost the link).  Presumably because it's not a million miles away from it's Jazz heritage, which - being a car - does idle at stoichiometric.

 

So, even though the engine may be running closed-loop and stoichiometric at low speeds and small throttle openings, it might well still benefit from a richer mixture.  For what it's worth, under other conditions it might well benefit from running leaner than stoichiometric - steady speed cruising type conditions - giving better fuel economy.

 

The truth is that stoichiometric is rarely the "ideal" mixture in terms of performance and fuel economy.  It is really only used because a normal three-way cat requires stoichiometric to work properly.

 

The biggest concern I have is that the makers of the after-market boxes might, or might not, have a clue what they are doing.  There is no industry body for policing standards; the box might cure one flat spot and induce two others (or hammer the fuel economy); and so on.  Who knows what it's doing to the mixture under the enormous range of speeds and loads an engine experiences?

 

I would only trust one if I could instrument it first and observe what it is doing.

  • Like 1

Share this post


Link to post
Tex

Just a thought - it might be worth having the balance of the throttle bodies checked. BMW boxers run much nicer when they have been balanced. I’m assuming Honda (like Triumph) do it on a computer these days?

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×