Low-Speed Bucking and Lurching

[JeffOlson]

How does one entirely eliminate low-speed bucking and lurching on a modern EFI motorcycle? Is it even possible? Do all new motorcycles buck and lurch at low speed? If not, which ones are the smoothest? Harley-Davidsons perhaps?

One of Beetle's maps and GuzziDiag have largely cured my Norge of most of its low-speed bucking and lurching, but not all. (My Vespa GTS 300 is smoother.)

Even my V-8 BMW, with an 8-speed automatic transmission, is not very smooth. It is really annoying. Years ago, I had an old V-12 Jaguar with a 3-speed automatic transmission and four carburetors. Now, that was smooth (though it had other issues)!

[LowRyter]

uhm, what?   

I don't have the problem on any vehicle.  If you're lugging the engine, then shift down or slip the clutch.

otherwise, I am clueless to the problem. 

[JeffOlson]

I must be doing something wrong, then...

[twowings]

Make sure your throttle cable is adjusted correctly...

[Gliderjohn]

I noticed it some before the break in service. Not been an issue as I can cruise just fine at 20-30 mph. Two things maybe, first I may have just got use to it if minor and second FI as a whole has a quicker "hit" when cracking the throttle than a carb bike will. Long story short, no it should not be bad enough to be annoying.
GliderJohn

[pete roper]

What sort of engine speed, road speed, throttle opening are we talking about Jeff? My Griso will pull cleanly from 2,500 my Stelvio, for some reason, not sure why yet, will pull cleanly from even lower! 

Pete

[guzzisteve]

Make sure your throttle cable is adjusted correctly...

Take all the slack out of the pull cable(top) w/bars to right or left so that it doesn't rev up w/you turn.

[Tom]

Sounds like your rpm's are too low.  Someone said it earlier.  You're lugging engine.  On lean fire engines.....more r's.  On Moto Guzzis raise your rpm's to 4k to 5k cruising.  Shift above 5K.  If you ride it like a HD.....wrong.

[Sasquatch Jim]

  I've been bucking and lurching at low speed for years now, Oh, you mean the motorcycle.

[Tom]

 

[twowings]

  I've been bucking and lurching at low speed for years now, Oh, you mean the motorcycle.

For you, I suspect a fueling problem...

[rocker59]

I have never had a problelm with this bucking/lurching on an EFI Guzzi.

I did have it on a 2003 BMW F650GS.  Real annoying.

My Guzzis have been great!

[JeffOlson]

I try to keep the revs well above 3,000 and shift between 5,000 and 7,000 RPM. It's the low-speed, 5-10 MPH "freeway" riding that is difficult, where the throttle acts a bit like an on-off switch.

[fotoguzzi]

has your TPS been calibrated?

[pete roper]

I doubt building a map for it will be a problem, it's busting open the protocols to read and write that are causing the problems. We're hoping to be able to help with that but we need to be able to 'Piggy back' a map upload to do it.

To do this with any accuracy requires Mark to be around to hold my hand and run the sniffer software since we live 300km apart and he works in a demanding full time job this makes it difficult. It may also of been made harder by Piaggio having made it so that since my subscription has expired I may not be able to perform map uploads with PADS to 7SM bikes but I'm not sure on that yet. There is a Cali Custom in my workshop that I'm pretty sure has an 'Upgrade' waiting for it in PADS. It'll be interesting to see if it allows me to do it.

Pete

[Chuck in Indiana]

One of Beetle's maps and GuzziDiag have largely cured my Norge of most of its low-speed bucking and lurching, but not all.

To me, digital control of fueling is comparable to a digital recording vs a vinyl record. There is a harshness there that can be very subtle or not subtle at all.  My 07 Norge was terrible at small throttle openings and low speeds. The Kid was following Dorcia and me at Bikeweek, and he said, "Now I know why they call it a CARC. Clanks and Rattles Continuously."  With that bike, you had to use the clutch constantly to keep from 

Low-Speed Bucking and Lurching

Yes, I had the throttle cables adjusted and throttle bodies balanced..

[Nic in Western NYS]

Linear response to subtle throttle inputs at low rpm is my acid test for whether I'll enjoy driving a car or bike.  Without that, I move on.

[tris]

My B11 had a "on/off" throttle response from low setting until I took all bar a gnats whisker of slack out of the throttle cables.

I probably only had a couple of millimetres slack max at the bars to start with but it was enough

No idea why it works, but it definitely does.

[sib]

As others have commented, if there's too much throttle cable slack, it could cause low speed lurching.  Mine disappeared when I properly adjusted the cables on my V7II Stone.

[JeffOlson]

As others have commented, if there's to much throttle cable slack, it could cause low speed lurching.  Mine disappeared when I properly adjusted the cables on my V7II Stone.

I will definitely have that looked at when I take the bike back to Moto International for its next service... (I must be one of the few who actually likes paying someone else to work on my bike!)

[Gliderjohn]

From JeffOlson:

(I must be one of the few who actually likes paying someone else to work on my bike!)

I wouldn't say I like to pay but it beats me F-ing it up worst and then paying even more to get things right.
GliderJohn

[JeffOlson]

From JeffOlson:
I wouldn't say I like to pay but it beats me F-ing it up worst and then paying even more to get things right.
GliderJohn

 Yes, I should not have said "like" but "don't mind" instead!

[sib]

From JeffOlson:
I wouldn't say I like to pay but it beats me F-ing it up worst and then paying even more to get things right.
GliderJohn

I have an inborn distrust of hired hands.  Sorry, no offense intended, but I've learned the hard way that if I want something to be done right, I have to do it myself.

[JeffOlson]

^ I do, too, but I also want to do my bit to help keep my dealer in business.

[KraZ440]

I'm dealing with the bucking and lurching on my 2016 Stelvio. I see it at lower speeds (even in 1st gear). Once I'm going fast enough to be in 3rd gear, I don't notice it much anymore. I adjusted the slack in the throttle cables this weekend, but haven't been able to take it on a test drive yet. Hopefully that will help some.

I've also seen comments about throttle body balancing, TPS reset, better fuel filter, and new ECU map (which are all on my ToDo list).

I'm probably a little more sensitive to it than many here, since my Stelvio was a BIG jump in power/weight/height for me after too long being off a bike, so I'm still getting used to her. I guess I just need to ride more. 

[SportsterDoc]

I only notice it at very low speed (10 - 15 MPH, first gear) when cold.
OK once warm.

[80CX100]

I must be doing something wrong, then...

No you're not,,, I've owned and ridden lots of carbed bikes over the years,,, ALL were smooth down low,,,

I've only owned 2 EFI bikes and both are scarey trying to ride slowly in parking lots, ultra low ie walking speed, starting from a stop on a slow turn etc.

I put a power commander on my VStrom, and balanced the TB's and Throttle secondaries,,, helped a lot, but didn't completely cure it.

My CalVin was not near as bad but still not as smooth as any of my carb bikes.

What I have found really helps smooth things out and feel much more controlled at slow speed is dragging the rear brake slightly,,, I believe the technical term is trail braking

fwiw ymmv

Kelly

[beetle]

It's all about throttle response. Fuel injected bikes have better throttle response. Adjust the slack in the throttle cables. Make sure the throttle bodies are well balanced. With a big lump like the 1200 8V, you've got a lot of torque to tame.

I can probably fiddle with the throttle correction in the map, but if you're stuck in low speed traffic you may want I consider adding something like a G2 throttle tamer.

[SportsterDoc]

No low speed issues, hesitation or any issues with my 2012 Bonneville, but the dealer programmed with an Arrow tune, no charge.
Wish the MG dealer could do something like that.

[JeffOlson]

Thank you, everyone, for the replies. I will have the bike serviced in a few hundred miles and have Moto International look at and adjust everything. (A throttle tamer might help, too.)

I paid more attention this morning on my ride to work. Part of my 21-mile commute is bumper-to-bumper "freeway" riding, often in first gear (if that!). Below 3,000 RPM, the throttle acts like an on-off switch as I accelerate and then decelerate to go with the "flow" of traffic trying to make it north across the "border" (no, not California, though it seems like it; the Boone Bridge, just south of Wilsonville). Lots of bucking and lurching today!

I seem to recall my first Norge running much better at very low speeds with an Agostini "silencer" with the DB killer removed. The ECU seemed to trim around the freer-flowing exhaust, and there was not so much bucking and lurching. But maybe I am imagining things...