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Hey everyone, I got my 2008 Sportster XL1200 Custom one month ago. I've never owned a Harley before, only Honda's. I noticed it's extremely "jerky" mainly in 1st gear going slow. I know it's a 1200cc and doesn't like to go slow. But, it just seems to be a little too "jerky" , more than normal. What could be causing that?
 

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Greetings, I saw your other thread about the clutch being stiff. I wonder if a clutch adjustment could fix both of your issues.
 

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My wife's 2016 Forty-Eight is "jerky" in first gear - especially at lower speeds. It just takes some time to get used to it and "finessing" the clutch at lower speeds. I think it has a lot to do with how it is geared.
 

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Can you compare it to the Hondas you have ridden previously? Are you suggesting that it is abrupt when throttle is applied? Does this occur at any rpms, or only when giving it a lot of throttle from low rpms?
 

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Hey everyone, I got my 2008 Sportster XL1200 Custom one month ago. I've never owned a Harley before, only Honda's. I noticed it's extremely "jerky" mainly in 1st gear going slow. I know it's a 1200cc and doesn't like to go slow. But, it just seems to be a little too "jerky" , more than normal. What could be causing that?
My 48 does the same, and I think it is normal or at least common for Sportsters. The reason is first of all that there is a lot of slack/backlash in the transmission. Not the drive belt, but the gearbox and primary chain. Unfortunately H-D accepts poor workmanship and large variance in tolerances, and this adds up. To give you an example, if you want to adjust the primary chain to reduce slack, you have to take into account that the two shafts are not straight so you must adjust the chain where they have the most distance from each other. The fact that H-D even has to put this in writing is embarassing, but unfortunately that quality level is fine for them.

The issue of jerkiness is amplified by the nature of the engine that has the well known uneven firing intervals, and Sportster engines have relatively low inertia which amplifies that property even more.

Check and adjust the primary chain and the belt drive if necessary, following the correct procediure. It will probably not do much difference, but it is the only thing you can do.

If H-D bothered to reduce the tolerances the Sportsters would be less jerky and have less piston slap noise, and last longer, but that is not going to happen due to cost. It seems H-D reduced their quality dept. and used the money on the marketing dept. instead.

Maybe some will say that their Sportster is smooth, and that might be so if they are among the lucky ones where the tolerances happened to be in the acceptable range. Thats the nature of tolerances.
 

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My 48 does the same, and I think it is normal or at least common for Sportsters. The reason is first of all that there is a lot of slack/backlash in the transmission. Not the drive belt, but the gearbox and primary chain. Unfortunately H-D accepts poor workmanship and large variance in tolerances, and this adds up. To give you an example, if you want to adjust the primary chain to reduce slack, you have to take into account that the two shafts are not straight so you must adjust the chain where they have the most distance from each other. The fact that H-D even has to put this in writing is embarassing, but unfortunately that quality level is fine for them.

The issue of jerkiness is amplified by the nature of the engine that has the well known uneven firing intervals, and Sportster engines have relatively low inertia which amplifies that property even more.

Check and adjust the primary chain and the belt drive if necessary, following the correct procediure. It will probably not do much difference, but it is the only thing you can do.

If H-D bothered to reduce the tolerances the Sportsters would be less jerky and have less piston slap noise, and last longer, but that is not going to happen due to cost. It seems H-D reduced their quality dept. and used the money on the marketing dept. instead.

Maybe some will say that their Sportster is smooth, and that might be so if they are among the lucky ones where the tolerances happened to be in the acceptable range. Thats the nature of tolerances.
What is your source for this information?

Have you measured the backlash of sportster transmissions?

How do you measure backlash of a chain?

Have you measured the runout of the "shafts" in the primary?


Sportsters have "low inertia"?

Where do you come up with this shit?
 

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The poster has been reading posts on the web. You will find any and everything on the web.
Back to the original question... Sounds like there is nothing wrong with the bike, just a matter of getting use to a totally different bike than a Honda. Sportsters are a little less "refined" than your previous Hondas, they also have a relative large engine, with large parts, and at slow engine speeds can easily lug. Learn to use the friction zone of your clutch when riding slow,( that's something you most likely never did on a Honda, as the Honda was likely geared lower and somewhat more "civilized" in first gear).
Sportster clutches are somewhat hard to pull, it takes a while to get use to, but it will come. Hang in there, give it some time, you'll get the hang of it.
 

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What is your source for this information?

Have you measured the backlash of sportster transmissions?

How do you measure backlash of a chain?

Have you measured the runout of the "shafts" in the primary?


Sportsters have "low inertia"?

Where do you come up with this shit?
Thank You. You saved me the trouble of saying that.
 

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Sorry, I do not want to start a fight here, but really just trying to explain the reasons for the “jerkiness” being described.
As a mechanical engineer specializing in gearboxes and owner of a Sportster, I have both the technical understanding and the personal experience to know what is the underlying reasons.

I could reply to your questions but what is the point if you just get annoyed or aggressive?
 

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You must know that chains stretch unevenly right? I would love to see a bent transmission shaft. I know how they are made and know they aren't machined and ground in a bent condition. If you have ever put a pressed up crank between centers and checked with indicators you would know that if the drive side wobbles so does the timing side. Sportsters drive the cams with gears. That doesn't leave much room for a wobbling crank. I think you don't know what you don't know.
 

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Sportster Dane is the only one who answered the O.P.'s question. The V twin with both connecting rods using a common crank pin has uneven firing pulse's. This quite different than the design of most other engines and is the major contributor to the chop or jerking you notice at low speed. It is also what gives us the famous Harley exhaust sound. You just won't get it on an engine that fires evenly.
 

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Christina - What you're experiencing is the nature of the beast. At low speeds such as you'd find in a busy parking lot or making a U-turn you need to feather the clutch, using the clutch's friction zone to reduce jerkiness. Feathering the clutch allows for slow speed with higher than idle RPM. The clutch lives in an oil bath that reduces heat and is made for that purpose, unlike a car clutch which is dry and can burn out easily. This is something that is basic to a Harley in general. Please ignore comments that talk about bad quality control etc; do you really think that a company with a history like Harley would be around as long as it has with poor quality control and engineering? Ask yourself why a claimed mechanical engineer specializing in gearboxes would buy a machine with flawed machining. I, too, am a new Harley owner for the first time, I understand the jerkiness you describe, and with 5K miles on my 02 Low Rider I'm getting used to the quirkiness of my beautiful machine. These things are not like an imported bike which is why they have a world wide following. Hang in there and keep reading the forums but take with a grain of salt the extremes in opinion that you find here. Smooth shifting and operation, especially at low speeds, comes with more miles driven. By the way, all of this is assuming that the used bike you bought is mechanically sound. Have someone you trust who rides Harleys to test ride your bike or take it to your local dealer just to gain confidence that all is mechanically correct with your bike.
 

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Sorry, I do not want to start a fight here, but really just trying to explain the reasons for the “jerkiness” being described.
As a mechanical engineer specializing in gearboxes and owner of a Sportster, I have both the technical understanding and the personal experience to know what is the underlying reasons.

I could reply to your questions but what is the point if you just get annoyed or aggressive?
What sort of gearboxes do you design?

As an aside, Evo Sportsters do last a long time without rebuilds-frequently as long as Japanese inline 4s.
 

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Try working on your Friction Zone at low speeds in a empty parking lot.
 

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Christina - What you're experiencing is the nature of the beast. At low speeds such as you'd find in a busy parking lot or making a U-turn you need to feather the clutch, using the clutch's friction zone to reduce jerkiness. Feathering the clutch allows for slow speed with higher than idle RPM. The clutch lives in an oil bath that reduces heat and is made for that purpose, unlike a car clutch which is dry and can burn out easily. This is something that is basic to a Harley in general. Please ignore comments that talk about bad quality control etc; do you really think that a company with a history like Harley would be around as long as it has with poor quality control and engineering? Ask yourself why a claimed mechanical engineer specializing in gearboxes would buy a machine with flawed machining. I, too, am a new Harley owner for the first time, I understand the jerkiness you describe, and with 5K miles on my 02 Low Rider I'm getting used to the quirkiness of my beautiful machine. These things are not like an imported bike which is why they have a world wide following. Hang in there and keep reading the forums but take with a grain of salt the extremes in opinion that you find here. Smooth shifting and operation, especially at low speeds, comes with more miles driven. By the way, all of this is assuming that the used bike you bought is mechanically sound. Have someone you trust who rides Harleys to test ride your bike or take it to your local dealer just to gain confidence that all is mechanically correct with your bike.
True I bought a new Harley, but I would have been happier if the tolerances in the transmission were smaller.
As you can understand I am not impressed by the quality. When I picked up my new H-D it had excessive vibrations due to faulty balancing of the wheels. The dealer had to remove about 50% of the lead on both wheels. That solved the issue, but it just shows the lack of quality and control.
Anyway I like the bike, but it looks better than it drives :)
 
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