I wouldn’t worry about it. I mean, how much time do you really spend at that RPM?

 

That’s the thing, any time you Leave from a stop the motor will cross over 1500rpm on the way up and down. I don’t cruise at 1500rpm but every time it crosses it vibrates pretty good. I’m not worried if it’s normal. If no one else has this issue then I would say something is off on my bike and I’ll look into it further.

 

Not normal. Could be several things like compensator, or as mjwebb suggested motor mount or stabilizer bar.

 

Also could be a loose primary chain or even the tune.

 

Have you had the ecm tuned / dyno'd? You might have an odd (to your specific bike's conditions) ignition timing at 1500 rpm in your map. I'd certainly try another dealership. I know we've got one smaller H-D dealer around here that is pretty poor when it comes to diagnostics. The bigger dealers around here have much better techs for the modern bikes

(spit-balling possibilities)

 

Nearly impossible to get a chart that says anything meaningful (or anythingat all for hat matter) at 1500

 

Vibrations gone! Installed a power vision from fuelmoto with their map and the bike has never run this smooth. From day one I thought mine wasn't as smooth as the one I test rode. I thought it was in my head but now I know how smooth the M8 is supposed to be. I'm a happy rider again.

Also big thanks to fuelmoto. I ordered my power vision Wednesday morning and it was at my house Thursday afternoon. Excellent service!

 

I have a hard time believing that this vibration was due to tuning of the motor. My 2018 RGU is completely stock, including and especially the tuning of the motor, and it doesn't make any unusual or objectionable vibrations. I rode one other 2018 RGU, and it was the same as mine. I don't see how completely stock bikes from the factory would vary in their tuning.

When I read the last post from the OP I thought I was reading an ad for FuelMoto.

 

I had a mysterious vibration for awhile. Try this...get up to about 65-75mph pull the clutch and coast for a few feet then release it. The revs should go way up basically do a few hard down shifts. See what happens. Mine went away after doing this. Was chain tensioner in primary. Worth a shot. Someone here recommend it to me as well.

 

Glad the OP got his problem squared away. FWIW, my 2018 Road King engine is smooth as silk at 1500 as I accelerate though to cruising RPM. But hey, his problem is solved so that's great!