I don't visit here often but I know there is a ton of knowledge here with you sportster guys. So I'm gonna ask a question that I know is hard to answer without actually seeing/hearing the bike in person.

I have a 2008 Rocker C. My motor is nice and balanced, smooth and quiet (as quiet as a Harley engine can be I guess). No loud clacking or rattling (for lack of a better term).

My wife owns a 2011 1200 nighster. Only 3000 miles on the bike. The bike rides fine as far as throttle response and power. No weird color smoke coming from the exhaust or anything like that.

When I ride her bike I do notice that at high speeds (50 mph+) the thing shakes like hell. I also hear a lot of clanking and rattling (for lack of a better term) coming from the engine.

I hate to sound like a total newbee but keep in mind that this is the first and only sportster I've ridden on a consistent basis. I rode a 48 on two different occasions the year it was first released, I frankly don't remember if that shook or not or if it was a rattling beast like my wife's sportster is.

The only mods done to the engine are HD high flow air cleaner, v&h short shots and HD race tuner.

I'm hoping you guys who own sporties can put my concern at ease. I fear the engine is knocking (miss firing) and We don't know it. Never thrown a code or anything like that.

I know we like pics here in the forum so I attached one. The grey/blue is my rocker with clip ons.

 

Check the motor mounts/rubber isolators. Just a guess. A little valve-train noise is normal, but don't lug a Sportster. They like a little bit of RPM. I wouldn't get into 5th on my OL's '04 1200 until about 60 mph. For the vibration concern, I guess the other things to check would be neck bearings or an out of balance wheel.

 

Gonna check the motor mounts, can't believe I didn't think of that.

I'll check for play on the front end as far as the neck bearings go. Wheels just got put back on the bike after being balanced and white walls put on.

I'm planning to take the bike to the dealership and have one of the techs ride and see what they say.

I'm hoping you guys can give me some input before I put myself at the mercy of the stealer.

 

I can't see it being neck bearings as those would likely vibrate even at lower speeds. However, you never know so play it safe. My first guess was engine mounts. My second guess could be a improperly tuned race tuner.

 

I don't think it's the neck bearings either. The bike has 3000 miles on it and it doesn't get ridden much. I know that sometimes doesn't mean anything.

when it vibrates, it does it at high rpm and it feels like the whole bike vibrates not just the handle bars.

I did some reading and I saw a few posts about compensator nut being loose.

Anyone have any insight about that.

 

Hey Alain,

I have a Heritage and two Sportys. The top end noise on a sporty is going to be a bit noisier than your Softail.

However, it should not be shaking at all. Mine are rock solid up to 100 MPH+

I know you just got new tires installed, and paid for them to be balanced...but might be worth double checking. I had a new tire installed & "balanced" a couple of months ago. But it wasn't balance and the bike shook to varying degrees at different speeds. (wasn't one of the Sportys)

Since the nightster is spoked, I would check the spokes also.

Also, like was mentioned, keep the RPM's up...like 3000+

The Sportys don't have knock retard like the later Twin Cams. So if there is a chance it is pinging, need to get that tune adjusted. It won't throw a code if it pings.

 

I kind of get the same thing out of my 2014 Sportster 1200C during a higher rev of the engine. Sends a buzz into the handle bars that kind of reminds you of holding on to an electric fence. Tires a factory balanced Michelins.

 

Thanks for the info Kevin. I didn't know that if the engine was pinging I wasn't going to get a code. Thank you for that info. Is there any other way to determine if the engine is pinging other than hearing the knocking?


I'm glad Yogie replied cause the word he used is a better way to describe the vibration. I think I might have used the term shaking. A "buzz" into the handle bars and foot controls is a much better way to describe what it feels like when you're going down the road at 50+ mph.

 

Curious on this as well. I have some bling on my '11 Custom, but only mod is SE slips and a stage 1 with the flash. The sweet spot is just above 2800 rpm and is as smooth as my King.

Not too sure on the motor mounts as the bike has low miles, but you never know on these things. A loose or cracked rubber mount can cause that 'buzz' at speeds.

 

the injectors also make´s alot off noise, try opening a hood on a vw golf gti mrk6 it almost sounds like a diesel
but i thought there was a safty with knock retard what is the thing in the middel off the head on the rear cylinder then?????????


regards
RIX