Hello everyone need some help, I have a 1999 Fatboy bought used about 3-4yrs ago in good shape no major issues other than leakey valve giuides. My issue is a wobble at hi speed, its been wobbling for a couple years now and havnt been able to figure it out I did lower the front 1" and back was already lowerd 1-1/2" when I bought it. so, Here is what I have done to it to try to figure it out:
with stock solid wheels and proper air pressure checked run out with new timken bearings and races, No Wobble Fix
Replaced tire with new Dunlops, stock 16"'s, others were staring to crack. No Wobble fix
Checked neck bearings, then replaced with new and races, No Wobble Fix
Raised front back to stock. No Wobble Fix
Replaced wheels with fat spokes 21" front 16" rear still No Wobble Fix.
So last week rode to Reno and actually noticed that my bike didnt Wobble when I took it up to 70-75 in 4th gear but when shift in 5th gear its started Wobble. In 5th gear Wobble started at 60-85 and any time in between but not in 4th at those speed.... Can tranny shaft bearing or 5th gear bearing be bad? Any suggestion what to look for?

 

I have a 99 Fatboy an never had a problem. It came with spoke wheels an new Dunlop tires. It did feel like the front end was very light feeling over 80 mph....I added a windshield an it really helped stablize the bike on highway.

 

Everything that needs to be checked for the wobble should include, but not be limited to:

• Air Pressure
• Rear Wheel Alignment 0.793mm In Between Side To Side
• Tires Not Balanced
• Rim / Tire Out Of Round
• Steering Head Bearing Incorrectly Torque
• Wheel Spacers
• Wheel Bearing
• Engine Mount
• Transmission Mount
• Equal Amount Of Fluid In Both Forks
• Loose Axle Nut
• Caliper Alignment
• Neck Bearing Adjustment
• Swing Arm Pivot
• Shocks Rear Aligned Equally
• Top Of Forks Not Extending More Than 10.66mm - 12.7mm And Be Equal
• Steering Stem Nut
• Swing Arm Bushings

 

Put it back to stock height. [no really,try it]

 

All of what you guys listed has been checked and redone couple time including back to stock height and swing arm bearings replaced. Engine sits on frame so no engine mounts, 99 Softail. Im thinking its in primary or transmission bearings. I have a batwing fairing also no difference in wobble other than speed when it happens but still in 5th gear. Ill post my finding after I tear into primary and bearings in a couple weeks.

 

+1 on neck bearing adjustment (being too loose) and front axle nut, especially having even spacing on front axle nut adjuster (very very important).

 

Another thing to look at is the fork fluid. Went with the 15wt se fluid made the ride ten times better. It stiffens everything up up front. It's easy to do with dear lift also. Best money I've spent in year

 

Good post by next in line. Anything out of balance on a bike can result in a wobble, because the fork hinge is the path of least resistance. I wouldn't think a bad tranny bearing would result in a wobble though, but maybe. If the bearing was that bad, I would think e tranny would grenade first. I know some people have had issues with bat wings on softails. Something about the triple tree geometry. Do you have the wobble without the batwing?

 

I say ditch the batwing faring and see how it goes. I thought I read somewhere that another softail owner
Had that problem and it turned out to be the faring.

 

Have you though about checking your front end for a bad or defective spring or inter shock parts ?
You said the back was lowered before you bought the bike , I would double check them to.