I bought a pre-owned 2010 Street Bob. It has the same engine as my boyfriend's Crossbones, but when I start it, this bike is like a 3yo with ADHD, it just wants to go. It has aftermarket pipes on it, but we're not sure what kind since there doesn't appear to be any stamps, but we're pretty sure it's had either a chiptune or some sort of engine mod. When I start it, you can see the horn cover jumping. I've seen other Street Bobs running and they don't do the same thing. Any idea what could have been done?

 

Unless there's a bolt-on tuner like a PowerCommander or FuelPak visible then there's no way to know what's been done to the tune. You would have to get a tuner that programs the ECU like a SEPST or TTS and download the tables off the bike and inspect them.

 

Actually not the same engine. The softtail twin cam is counter balanced so it would be smooth at idle. The Dyna has a non-balanced rubber mounted engine. They hop around more at idle, it is normal. If it is excessively shaking you may just need new engine mounts (even on a 2010). But different cams could make the engine lope more as well.

 

Its definitely shaking more, I saw a street bob the other day and waited for him to leave (yeah,i know, stalker) so I could see if it reacted the same was, it didn't. I called the dealer to have him check the records, we'll see if he finds anything out. If not, I'll have to check those engine mounts. Thank you both!

 

FYI Two motor mounts on the bottom one on the top, change them all at the same time or you will eventually be replacing the old ones as they take the vibes and fail.

 

I had a similar experience when I traded my fat boy in and got the new SB. The rubber mounted engine shakes a lot more. Just enjoy The good vibes! You can also make fun of your guy because your bike will smoke his! Ha ha.

 

I've done 2 different set of engine mods on mine and it really shakes. I've put new motor mounts on it and it doesn't change.. also loosened the mounts up ,let it idle and then tightened them down again and it did nothing to stop or slow down the shake.
I have a feeling that my flywheel has slipped just a hair but I don't want to tear down the bottom end to find out.
It maybe something you have to live with unless you tear the whole thing down.

 

Shimming the mounts to get rid of the preload also helps, I did this on mine when I changed the front mount.

 

my front tire and horn both shake at idle since new but it smooths out right off the line. Do you have any vibration once your feet are up and your moving down the road?

 

It seems to be a smooth ride, honestly this is my first bike, so I don't have anything to compare it to. My dealer called back yesterday, nothing was ever mentioned about any modifications, but he said he really doubts it's the engine mounts since the bike only had 21xx miles on it. For now it looks like it's going to remain a mystery and I'll chalk it up to a personality quirk. Granted, it's one hell of a personality quirk! (I love it!)