I have read several reviews on the Bandit 1250 that included comments about surging at small throttle openings. I would like to know what speed/RPM/gears this occurs.
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Surging at small throttle openings.
- Thread starter WMU_BRONCO
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About what speed would correspond to 2,000 RPM in 3rd gear and in 4th gear?
I'm now convinced that I have these "surges" spoken of.... But given that I had the BMW R1150 single-spark NOTORIOUS for it's 'surge', I would have to say the Bandit's is very very subtle. Contractually bound to use the old fashion Bosch fuel injection, fuel readings/responses/delivery were too slow for the new lean running "green" engines. I got used to it over time, and actually rode the bike too fast to be bothered by these surges.
When I'm cruising in top gear on the Bandit, steady throttle reveals just a hint of not-so-smooth fuel delivery.... it kinda surges. I found it interesting when I read a post by somebody here who avoids from cruising in top gear at the slower freeway legal limits, choosing instead a lower gear where throttle response is NOT preceded by a lag. His findings were that his fuel economy actually went UP! His theory was that cruising in too low a gear did not so much lug the engine, as it did tax the fuel delivery. He theorized that twisting the throttle in too low a gear initially squirted enough (too much) fuel to get the engine & fuel injection motated and (back) in the range of it's most efficient operating rpm.
I've experimented with his premise in mind, and found that surging is more pronounced if one is in a gear too low for the speed & conditions. Although frankly, I think my (once new) bike could use a little throttle body synch' to get it back into optimum performance with minimal surging.
When I'm cruising in top gear on the Bandit, steady throttle reveals just a hint of not-so-smooth fuel delivery.... it kinda surges. I found it interesting when I read a post by somebody here who avoids from cruising in top gear at the slower freeway legal limits, choosing instead a lower gear where throttle response is NOT preceded by a lag. His findings were that his fuel economy actually went UP! His theory was that cruising in too low a gear did not so much lug the engine, as it did tax the fuel delivery. He theorized that twisting the throttle in too low a gear initially squirted enough (too much) fuel to get the engine & fuel injection motated and (back) in the range of it's most efficient operating rpm.
I've experimented with his premise in mind, and found that surging is more pronounced if one is in a gear too low for the speed & conditions. Although frankly, I think my (once new) bike could use a little throttle body synch' to get it back into optimum performance with minimal surging.
achesley
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I agree with Fittysom'n. After many years on R11 Series BMW's my DL1000 and GSF1250S is nothing to be concerned about. I felted it just a touch more after installing the Yosh can but still not near what my 3 BMW's were like.
As to what speeds at 2000 in 2,3 and 4 gears. I'm just not sure. I just have not paid attention although I quite often drop down at low as 35 mph in 6th and just gentle roll on when speed limit increases.
As to what speeds at 2000 in 2,3 and 4 gears. I'm just not sure. I just have not paid attention although I quite often drop down at low as 35 mph in 6th and just gentle roll on when speed limit increases.
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I think what you are experiancing is just all of the raw power of your Bandit just waiting to be released, so open up that throttle and give your Bandit what it's craving for. 
achesley
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I think what you are experiancing is just all of the raw power of your Bandit just waiting to be released, so open up that throttle and give your Bandit what it's craving for.
That's one way to put it. 
suzukijo
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uh, ...we used to call that lugging.
either rev it up, downshift, or slip the clutch.
that anyone would that there is something wrong with the motorcycle, and not with the operator, I got this investment scheme, where you are guaranteed not to loose, contact me off list.
either rev it up, downshift, or slip the clutch.
that anyone would that there is something wrong with the motorcycle, and not with the operator, I got this investment scheme, where you are guaranteed not to loose, contact me off list.
What I was referring to is not lugging - lugging requires a load. When you're on a dead flat road or even going slightly downhill and the throttle is open a small amount to maintain around 30 (IIRC) in a mid gear like 3rd, there is a feeling like the bike is running out of gas. The first time this happened to me I pulled over to the side of the road to see what was wrong with the bike...
Yes, you can avoid that spot by staying at a higher rpm but that doesn't mean the surging is not there. I think the O2 bypass fixes this. I did a TFI at the same time, so I'm not exactly sure which one cleared up the problem.
Yes, you can avoid that spot by staying at a higher rpm but that doesn't mean the surging is not there. I think the O2 bypass fixes this. I did a TFI at the same time, so I'm not exactly sure which one cleared up the problem.
"Surging"....., it ain't 'lugging' (the engine).
As I understand it, the computer in the fuel injection system is constantly reading, evaluating, and responding to the need for fuel. Some folk believe they have had success disconnecting the Throttle Position Sensor on certain bikes. In an attempt to keep it all "green" the fuel injection is instructed to deliver juuuuust the right amount of fuel (not too much!) to meet the demands of the engine, rider, and conditions. On my 2001 BMW, it was said that the old Bosch fuel injection took readings and responded accordingly just a few times per second. The newer fuel injection systems are taking a reading and responding MUCH faster than the older systems.
There is also a point where the fuel injection interprets the need for fuel to be virtually non-existent; this is just between on-throttle & off-throttle..... So the fuel injection's brain kicks the fuel delivery into a mode that provides only enough gas for the engine to 'idle'.
When I was looking recently at the new sexy super duper KTM Super Bike, the sales tech' explained to me that KTM has equipped the bike with TWO idle modes to deliver gas (or some'n like that). He said that when a motorcycle goes aggressively into a series of sharp swoop doopy banks, the fuel delivery system in traditional fuel injection systems cuts off the delivery of fuel and can be likened to a subtle 'chopping' of the throttle... this can cause a nasty kicking out of the rear wheel, upsetting the bike. So the SECOND idle mode kicks in and provides a constant flow of fuel when the rider is off the throttle; makes for a smooooth & controlled transition through the corners.
So unless or until a similar system is engineered into common street bikes (suddenly making them cost prohibitive), those of us sensitive to the subtleties of the oft' whined about "surge"..... will just hafta deal with it, OR THROTTLE OUT OF IT, ride babiee RIDE!!! WhoHOO!
Disclaimer:
I really don't know what the heck I'm talking 'bout here. Just sharing with you how my mind has interpreted bits & pieces of info'.....
As I understand it, the computer in the fuel injection system is constantly reading, evaluating, and responding to the need for fuel. Some folk believe they have had success disconnecting the Throttle Position Sensor on certain bikes. In an attempt to keep it all "green" the fuel injection is instructed to deliver juuuuust the right amount of fuel (not too much!) to meet the demands of the engine, rider, and conditions. On my 2001 BMW, it was said that the old Bosch fuel injection took readings and responded accordingly just a few times per second. The newer fuel injection systems are taking a reading and responding MUCH faster than the older systems.
There is also a point where the fuel injection interprets the need for fuel to be virtually non-existent; this is just between on-throttle & off-throttle..... So the fuel injection's brain kicks the fuel delivery into a mode that provides only enough gas for the engine to 'idle'.
When I was looking recently at the new sexy super duper KTM Super Bike, the sales tech' explained to me that KTM has equipped the bike with TWO idle modes to deliver gas (or some'n like that). He said that when a motorcycle goes aggressively into a series of sharp swoop doopy banks, the fuel delivery system in traditional fuel injection systems cuts off the delivery of fuel and can be likened to a subtle 'chopping' of the throttle... this can cause a nasty kicking out of the rear wheel, upsetting the bike. So the SECOND idle mode kicks in and provides a constant flow of fuel when the rider is off the throttle; makes for a smooooth & controlled transition through the corners.
So unless or until a similar system is engineered into common street bikes (suddenly making them cost prohibitive), those of us sensitive to the subtleties of the oft' whined about "surge"..... will just hafta deal with it, OR THROTTLE OUT OF IT, ride babiee RIDE!!! WhoHOO!
Disclaimer:
I really don't know what the heck I'm talking 'bout here. Just sharing with you how my mind has interpreted bits & pieces of info'.....
Before anyone goes out and tries this someone should point out that it's not the TPS that people disconnect, but the O2 sensor. If you disconnect the TPS the ECU won't know how wide open the throttle is or, consequently, how much fuel to inject. In fact, most injected bikes probably won't run at all with the TPS disconnected.
yeah.... I think it mighta been my fellow Bonneville owners (before the recent fuel injected models) who were disconnecting the TPS.... I didn't.
suzukijo
0
i guess what i meant to say, that small throttle openings is lugging, not what most people think.
some time back, i tried to describe the way i rode, and small throttle openings were not part of what i did (sorry bandit owners, i'm not riding one anymore). so one day i actually kept track mentally of what I did, and found that i either slipped the clutch to get the revs up, or simply wound out the engine, hardly ever letting the throttle keep attached solidly with the engine at low rpm.
its difficult for me to explain, but maybe my bike had the stumble, and i corrected for it, and years of having to overcome difficult to ride motorcycles with peculiar power deliveries, makes me stay away from finding the part that has hiccups, and stumbles, so to me, very light throttle in any gear is "lugging" it.
my suggestion, to overcome it, would be to simply pull in the clutch, get the revs up, and get moving. I also realised, i almost always used the clutch on both upshifts and downshifts, slipping the clutch to ease engagement, at every moment.
the only time i got rough with slamming the transmission was either in panic stops or unsettled about to throw it away situations. (few of those, but the last one did the hat trick)
some time back, i tried to describe the way i rode, and small throttle openings were not part of what i did (sorry bandit owners, i'm not riding one anymore). so one day i actually kept track mentally of what I did, and found that i either slipped the clutch to get the revs up, or simply wound out the engine, hardly ever letting the throttle keep attached solidly with the engine at low rpm.
its difficult for me to explain, but maybe my bike had the stumble, and i corrected for it, and years of having to overcome difficult to ride motorcycles with peculiar power deliveries, makes me stay away from finding the part that has hiccups, and stumbles, so to me, very light throttle in any gear is "lugging" it.
my suggestion, to overcome it, would be to simply pull in the clutch, get the revs up, and get moving. I also realised, i almost always used the clutch on both upshifts and downshifts, slipping the clutch to ease engagement, at every moment.
the only time i got rough with slamming the transmission was either in panic stops or unsettled about to throw it away situations. (few of those, but the last one did the hat trick)
dhula
0
I had a surging/hunting situation on my bandit for quite a while
It was in the 4-6 gears and started around 2500 and lasted till about 4500 as long as you were in those top 3 gears.
It only occurred while cruising so on steady throttle
Not sure if it's the same as your talking about but maybe the case
How did I cure it
After much stuffing around and TB syncs etc etc I disconnected the GPS (gear position switch, not global positioning system
)
This sorted the problem in an instant, only thing was I no longer had the neutral light on the dash. To fix that I reconnected the GPS after removing the PINK wire from the connector
Now I have no surging/hunting.
I still get the slightly harsh transition from off throttle to on throttle no matter how smooth I try to be so around corners (intersections) I just fan the clutch a little and that is my work around ATM
One thing to remember if you do this is that the ECU now thinks your bike is always in 6th gear (apart from when neutral is selected and indicated on dash) so if you do a TB sync you need to disconnect the GPS as it does make a difference.
But then again what you are talking about may not be what I had.
It was in the 4-6 gears and started around 2500 and lasted till about 4500 as long as you were in those top 3 gears.
It only occurred while cruising so on steady throttle
Not sure if it's the same as your talking about but maybe the case
How did I cure it
After much stuffing around and TB syncs etc etc I disconnected the GPS (gear position switch, not global positioning system
)This sorted the problem in an instant, only thing was I no longer had the neutral light on the dash. To fix that I reconnected the GPS after removing the PINK wire from the connector
Now I have no surging/hunting.
I still get the slightly harsh transition from off throttle to on throttle no matter how smooth I try to be so around corners (intersections) I just fan the clutch a little and that is my work around ATM
One thing to remember if you do this is that the ECU now thinks your bike is always in 6th gear (apart from when neutral is selected and indicated on dash) so if you do a TB sync you need to disconnect the GPS as it does make a difference.
But then again what you are talking about may not be what I had.
I've had the exact some problem several times. I even tried opeing it up (a lot) more and in lagged for a few moments and then took off like a rocket.
Old news and just my .02 worth. Like some others I disconnected (added the O2 bypass plug) for the O2 sensor and noticed a big difference right away at low speeds/RPMs. What I thought was a throtle controle issue on my part was, in fact, this low speed surging. The O2 bypass doesn't fix everything - just made my bike a little smoother at low speeds around town - no effect whatever on the highway.
ol dave
ol dave