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Discussion Starter #1
Hi all, I am new to this forum and this is my first post.

Just got a new Sportster 48, so far just 300 miles on it. According to the users manual it is fine to cruise at 50mph in 5th. However the vibrations are severe between 45 and 70 in 5th. At 75mph it is quite smooth.

I have no previous experience with Sportsters, and I am surprised of the magnitude of the vibrations. It is worst around 50mph and I hoped that the tires where oval or flat spottet, but they seem round. Also the vibrations cause a back and forth rocking motion rather than up/down, so I think it really is the engine vibrations.

I would like to know if a new Sportsters are supposed to run like that, of if someone has an idea about what could be wrong.

Sportster Dane
 

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Dane
I have a new Iron 1200 and asked the shop to check it out twice due to vibration.If it is too severe check the front motor mount for looseness and the belt tension.Otherwise I guess it is the nature of the beast. Mine is fine at 60mph but at 65 mph I can barely make out vehicles in my mirrors. At 75 mph it goes back to smooth again.Even though it vibrates more than I have gotten used to I love it. The Sportster just seems like I am back to riding a 'motorcycle' rather than a rolling couch.
Colt.45
 

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New Iron 883 here. Can't say much, but keep in mind that they build these Evo motors a little loose - it's one of the reasons they are (nearly) impossible to kill. Not unheard of to hear piston slap or other noises. Not sure if that might lend itself to vibrations or not.

If nothing else, keep an eye on it and see how things go. Dealer will likely tell you to go the 500-1000 miles before worrying too much as everything is 'seating' in the engine and learning to play nice with one another.

Just keep in mind you have a 2 year warranty, as well as the Freedom Promise by the end of next August. If anything is wrong, have it fixed on HD's dime.

Welcome from NY! Leather side up! :smile
 

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Sportsters from 2004 up have rubber mount motors. They will vibrate at a certain RPM range due to harmonics of the rubber mounts.
 

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What you are experiencing, is almost certainly a tire/wheel out of balance or out of round. You said the tires seem true, did you measure runout on the tires? have you had the balance checked? That type of vibration is not normal! Newer Sportsters are pretty smooth normally.
 

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Discussion Starter #8
What you are experiencing, is almost certainly a tire/wheel out of balance or out of round. You said the tires seem true, did you measure runout on the tires? have you had the balance checked? That type of vibration is not normal! Newer Sportsters are pretty smooth normally.
Bobf,
I think you are right. I found a hill long enough to stop the engine at speed, and coast in the vibration range. The vibrations are still there just slightly lower.
Now I increased the tire pressure to 60psi to see if that can help on an eventual flatspot.
Thanks to all for your replies.
 

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As others have said - It's under warranty so I would have the dealership look at it and take it for a test ride. You paid a lot of money for that bike so take advantage of that two-year warranty. My wife has a 2016 Forty-Eight. There is a lot more range in each gear and a lot of times, I'm still in 4th gear when going 50 m.p.h. If a tire is out-of-round or not balanced properly, they should be able to see that if they re-balance the tire.
 

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My '05 1200 is smoother than my '19 1200. Not sure why, but it's carbed while the '19 is FI. Maybe the gearing is a bit taller now. These two Sporties are my first HD bikes, but as far as I know, it's the nature of the beast. I've been watching the tach and it would seem that the engine likes to be above 2200 rpms before you can accelerate a tad harder without the vibration, and only in 1st through 4th gear. I don't use 5th until 45 MPH and only if accelerating lightly, and at 60 MPH if merging into traffic or whatnot, to keep the HP up in it's good range in case you need it. The torque limit is at a lower RPM than the HP max is, but HP is what speeds you up, while torque is what is actually moving all that weight. V-twins are just naturally set-up that way, just like a truck engine V-whatever. You will know if you are lugging the engine because it will be a violent shake and the engine will sound as if it's running on 1 cylinder. That is very bad for the engine and the oil pressure is so low at that point that you could scar bearings. It doesn't mean that will happen after one or two times, but continually doing that will eventually lead to a very expensive repair bill. I suggest just shifting later, which means keeping the RPMs up higher, which won't hurt a thing, until you get a better feel for it and do what works for you. Higher RPM doesn't always mean more fuel used, as these engines are now fuel injected and the TPS plays a major role in it. Translating that, the more you twist the wrist the more fuel used, even at lower RPM. Personally, I like the vibration. I have pinched nerves in my back and riding bikes is soooooo much better on my back than my car is. It's not like that for most people, but then again I'm not like, well, anyone else lol.

Here are what the experts in the 60s said about vibration....

 

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Discussion Starter #13
Main reason found and fixed

The dealer had both wheels off the bike to check the balance. It turned out that the balancing done by HD was ridiculous. After rebalancing the wheels the shaking is reduced by some 60%. The remaning is tolerable and probably due to the tires being slightly out of round.
 
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