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Tourer
Posts: 329
scotts valley, California | Since it was new, my Vision has had a little void between power on and power off that causes a little jerking motion kind of like an old car with a bad u-joint. It is most noticeable on a gradual slow down with the throttle just barely open. As the rpm drop the jerk occures at the point where minimal power on changes to compression slow down. Of course, down shifting solves the problem, but if I choose to give it just a little gas for a low rpm drift, it jerks back the other way. Blasting through the twisties on Hwy 9 in third gear, the same thing happens every time I let off the throttle to ease into a curve and, when I give it some gas to power through the curve, it jerks again. This makes for a jerky ride through the twisties at any rpm. So, any ideas? |
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Visionary
Posts: 1359
New Bohemia, Va | I thought someone was starting a post about me.
check your belt adjustment - but I also notice some lag at times. I'm usually hard on the throttle on the twisties anyways, so I don't notice it then, but cruizing through town I get it. |
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Tourer
Posts: 324
New Orleans, La, | What year is your Vision? The early transmissions and primaries from Victory had excessive amount of gear lash and hence the cause of the jerky power transition. Victory has tightened the tolerence betwen the gear mating surfaces and change the type of gear from straight cut to dog cut gears. All of this in an effort to cut down on gear noise and reduce gear lash. I believe this change took place starting the 2010 production run. |
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Visionary
Posts: 3204
Memphis | Early ECM software mapping has a hiccup right at the 1,750 rpm mark. (About the exact same time where we slow down and pull the clutch in just prior to stopping.) If you keep the revs at 2000 and above in the twisties you should never feel it. |
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Tourer
Posts: 329
scotts valley, California | My Vision is an '08, Kevinx'd. This is probably just something I'll have to live with. She even jerks running moderately hard in the twisties (25to3500rpm). Like the proverbial wolf in sheep's clothing, she goes like crazy from 35to5500rpm, but try to ride sanely and she bucks like an old cow! The old cow part of that is a slight exaggeration. I hope she didn't hear me. |
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Visionary
Posts: 1436
| That jerk is completely normal. Victory doesn't use any type of torque inhibitor so you get that take up lash. Believe it or not HD only just recently (past 2 years) began using one on their tour models. In any case it isn't anything to worry about as it won't hurt anything. |
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Tourer
Posts: 329
scotts valley, California | NORMAL JERKS SCARE ME! Thanks for the feedback, gentlemen. It sounds like all of us deal with the same situation, and I am the only one who felt like whining about it. OK, I'll suck it up. Even the best bike in the world has little idiosyncrasies. |
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Tourer
Posts: 432
Gettysburg, 2008 Tour Premium | Does your bike have Lloyd's IAC. The IAC valve helps a lean part throttle and the resulting abrupt throttle surge. |
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Tourer
Posts: 329
scotts valley, California | Don't know about Lloids IAC. How do I find out? |
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Tourer
Posts: 457
Green Bay, WI United States | E-Mail him or just order the part. I understand it's an easy install and have seen nothing but positive feedback on this part. My 08 runs like a raped ape so I will not be doing any mods except the Lloydz exhaust gaskets.
Ride hard, ride fast, but above all, ride safe and free........ |
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Tourer
Posts: 415
| Lloyds IAC Valve gets rid of that throttle lag. Instant throttle response, just takes a little tinkering to get it right.
Plus will be a tad cold blooded once installed. Well worth it.
I used to occasionally get what I would call an air explosion from intake when getting on the throttle.
Never get it now. Takes a couple of minutes to warm up then throttle response is amazing!!!!! |
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Havasu, AZ | Just an FYI. It's called the IAV (valve). Designed to take the popping out of exhaust by choking down the air thereby richening up the AFR.
If I may; that surging you feel may be a symptom of a lean AFR and really should be re-tuned to get rid of it. |
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Tourer
Posts: 432
Gettysburg, 2008 Tour Premium | If you use Lloyd's fuel controller the IAV is the way to to tune the lean part throttle response. |
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Tourer
Posts: 494
Akron Ohio area | Part of the 2011 new transmission was a fix for gear lash in all but fifth gear.
Solution?
Buy an new bike. LOL |
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Visionary
Posts: 1436
| You can get rid of gear lash but if a bike is geared the way the 106 is and the response to throttle input is sensative, you are going to get some takeup lash. After all it ain't like the rear wheel is connected to the motor, lol..... Throttle control rather than chop and bang will reduce 95% of it. |
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Iron Butt
Posts: 802
| The ECM has a fuel cutoff "switch" built in. Many modern f/i systems use the same function. The idea is that when you close the throttle at higher RPMs the fuel is turned off. This accomplishes a couple of things, it is part of the emission control strategy and also helps to eliminate back firing on decel. When you hit 1750 RPM on closed throttle the switch turns the fuel back on again so the engine can idle. The problem seems to be that there is an excessive amount of intake air coming through the idle control valve on closed throttle so that when the fuel turns back on there is a surge. That's the jerkiness you're feeling when slowing to a stop and passing through the 1750 RPM range. My '10 never did it but my '11 does consistently. On the other hand, my '10 consistently popped on decel and my '11 never does so maybe the engineers changed something. I added a Lloydz IAV and it helped quite a bit. The surge is still there but not anywhere near as severe. I also tried to tune it out with my PC by playing with the mixture before and after 1750 RPM but that accomplished nothing. Any mods made about 1750 on decel are moot since the fuel is turned off anyway. A waste of time it turned out. This explanation does not address any kind of off/on surge at higher rpm as I haven't experienced that with either bike. My bike transitions perfectly everywhere except when going through 1750 RPM on closed throttle. BTW, Harley uses the same scenario but they seem to have transitioned it smoother. Besides, Harley's aftermarket controller allows the tuner to disable the switch entirely so the transition can be programmed manually.
In summary, if your particular bike surges at 1750 RPM on decel I don't know of a way to eliminate it completely but you can minimize it with a Lloydz IAV.
I hope this makes sense.
Marc |
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Is this jerk normal?