Hi,
I have a 2011 FXDWG but I guess everyone with the same engine on the Dyna can answer this:

Driving a stretch of almost 500 miles yesterday I felt something in the bike that I _don't think_ I have felt before.

When accelerating up on the highway, in fifth gear at around 55-60 MPH it smooths out but then at around 65 and up it starts to "rattle" (or vibration) before I gear up to sixth. I usually when accelerating are in fifth gear to maybe around 65 before putting in sixth.

The "rattle"/vibration was not just in the pegs but also under my seat. This is maybe totally normal but being tired in the back and behind after 450+ miles I started to "feel" things.

If you accelerate, in fifth gear and go up to 65+ MPH, can you feel the rattle/vibration from the engine under the seat? Why I am asking is that I think people say they are usually running at 65 MPH in fifth gear, and I just can't imagine cruising around with the vibration under my seat at that speed.

In fourth gear when accelerating up, after smoothing out at around 50 MPH it starts to rattle/vibrate at around 55 MPH.

Don't get me wrong, this could be totally normal and I really hope it is. I just want to make sure what others are thinking. In the pegs and handlebars I think it has always felt like this, it's just that it got so distinct yesterday when tired from driving non-stop the whole day.

 

Mine doesn't do that .. Sorry

 

Me neither.

 

i dont even think about 6th gear till about 75---sweet spots where the engine is smoothest seems to be in the upper rpm range...wish i had a tach to tell you more

 

How ya doin'

The "Sweet Spot on my '06 superglide is 75-80 MPH in 6th gear. that's 28-3000 RPM. If that vibration you refer to is the same as mine, it's valve train chatter. I've discussed this with my mech. and, he says "all the twin cams do it. Some more than others". Been thinking about going to gear drive for the cams to eliminate that. My SG has 112K Mi. on it, been there the whole time. No change! Anybody out there have some input on this?

 

What happens if you rev past that point? Does it smooth out? I don't have a tach so I can't tell you rpm but my bike does it in 4th gear at about 80 kph and 5th gear does it about 95 kph. If I go faster than that in those gears it smooths out.

A Harley tech told me that the emissions test is done at idle, 2% throttle and 3000 rpm. That is were the bike runs the leanest. I have assumed that is what I'm feeling and just don't hold it at those speeds / gears. Bump it up a gear and it feels so smooth you can't even tell it's running.

 

I remember when my bike was newer it did that but it must have went away with either age or pipes/tune because I rode my wifes 2011 street bob and I noticed it which brought up memmories. Not sure what's its due from. Motor mounts loosening up or engine loosening up? it will go away.

 

how many miles on it? mine started having a strange vibration at around 700 miles
when i had the 1k service done last week it went away.... mechanic said the front mount
was really loose.

 

Thread starter here,

Yes at those points; 80 kph in 4th gear and 95 in 5th, after that it smooths out and gets totally "still" but if I rev even more it starts to vibrate/rattle again with a higher frequency (of course since its more RPMs). This stage is what I have earlier only thought of as something that is in fast acceleration and never a gear/speed to cruise in but I hear people are cruising at these speeds.

Now yesterday when driving for long I felt that it rattled/vibrated at high frequency and I could feel it under my *ss which I hadn't done before.

low RPMS = "dyna shake" ---> mid RPM's (95-105 kph / 60-65 MPH in 5th) = "smooths out" ---> high RPM's = If I go past 65 MPH in 5th gear it again goes from smooth to a higher frequency vibration. Yesterday I felt this under the seat which I have never before been thinking of, which is why I am asking.

 

My high rpm vibes went away after about 1k.