so when i had stock apes I noticed a very small shimmy under decel.

now I changed to 4 inch z bars and blamo. at 50 miles per hour on decel it straight death wobble.

what gives. what are possible things that are loose or need checking out?

Its only on decel around 50 mph. do you think it could be from the vibration of the motor.

 

Your steering neck could be a little loose

 

How old is the bike? I have never gotten any wobble like you describe from any bike I have ridden.

 

Seems coincidental that the more stable bar arrangement would create more front end wobble.

Do check your front fork's fall away and make sure your risers are tightened to spec. Then check your engine mounts for tightness.

There are many more areas that can be causing your problem, but something is loose, out of balance or out of alignment.

Worn out wheel bearings or steering head bearings come immediately to mind. Sometimes they aren't packed good at the factory and after a few high pressure washings or just after few years of use they rust out, dry out or otherwise lose their firm and smooth movements.

I've had year old bikes that I've torn down to find dry and rusted bearings, just because I trusted that the bike was properly greased at it's initial assembly.

 

the bike is a 08 street bob. it has 4500 miles on it now. I have put about 2200 miles on it since i got it a few months ago.

i guess i need to send it to the shop for a sound looking over. sucks. its only at 50 mph on decel though. not so much fun. bars look **** though. i think i will get loner 4 inch riser extentions and powder coat them black.

any one else had these wobble issues?

 

my thought (just a thought) is there was a pre-existing problem. While 4" z bars are more "stable" per se, there is less leverage exerted by your grip on the bars to the front end. Bearings for the steerer tube are suspect. I ride a BMW from time to time and had this same wobble anytime I would decel from 90 or better...ended up being a slightly warped rim AND rotor...all but fixed the problem. New tire finally took care of it for good. Just my .02

 

Why would you bother to powder coat some loaner risers? Your first area of concern should be to correct the wobble issue. Or are you referring to a particular brand called "Loner" that I'm not familiar with?

At any rate, first address your problem before considering how to make it look pretty.

 

and IMHO this is one of those issues where the shop is gonna say "well we test rode it and spent a few hours lookin things over and it all looks good to us...now please pay $150 ( or whatever they charge ) for us to have done nothing and tell you your imagining things"

 

So, you say that when you are riding at 50mph and then decelerating, your bike begins to physically swaying back and forth within the lane of travel like if you were riding at, near, or above triple digits, but not accelerating?

are you sure you understand what the 'death wobble' is?

I guess my first real question is...Did you install the handlebars or did a shop?

What did you disassemble to perform said handlebar swap? Sometimes people will go much further with disassembly than needed.

 

Most everything else has been covered, so, Do you have spoke wheels? Have they ever been checked? If they have ever been tightened before check the holes in the hubs for play.