Recently I installed a Softail Custom front end on my Fatboy.. For the past couple months months I was also trying to fine tune the S&S G jetting.. My low end was excellent with an .031" intermediate.. But the midrange seemed to be flat not as responsive.. So tonight I decided to make more changes to the main jet and log some data on my Wego III.. As I was approaching 105 mph I felt the Death Wobble coming on so I let off and continued to log in 3rd and 4th gear in the 3000-4500 rpm range..I was pleased with my AFR's so I did another test hit.. This time trying to surpass 105 mph but this time it really started wobbling very hard actually scared me a little.. So again I let off I slowed back down and then it dawned on me, I remember watching a video where his English bloke was showing how to get out of a death wobble. So I started cruising back up to speed to see if it would happen again and sure as **** the death wobble turned aggressively but this time I laid down on my tank as instructed by the video and the wobble definitely disappeared I brought it up to 115 in fourth gear and I was very happy with the results.. I shut it back down and felt safe.. So if any of you guys start experiencing it do as the English bloke said, last down on your tank.. I tried to find the British Video but could not.. If anyone can find it please post it up.. It really was a very good video..

As for jetting the S&S G, I was going the wrong way with the main..I thought I needed more fuel but it turned out I needed less.. Currently in running .031"/ .070" and a 1.20 mm MIK in the T-jet.. Must say it's hawling as again..

 

Good info on laying on the tank with the wobble. I never had issues with my 1998 RK until I converted from EFI to carb. I noticed significant increase in power which is what I contribute the sudden wobble around 90 - 100 mph if I get on it a bit. Never had decent power in 5th gear before. I noticed the wobble was less prominent if I eased it up to speed. All the sudden I'm dealing with the wobble on the highway where I wasn't before so I appreciate you sharing the info. Will try it out. I don't really care about speed but I do want to feel safe and be able to keep up on the highway.

 

Such Death Wobble is sometimes associated with Not Enough Trail...caused by Mix and Match of Triple trees, and Fork Length...
But, also Improper "Fall Away" Too Tight would feel like a flat tire at lower speeds...Too Loose???? IDK...Never did that one!
Good Luck...
There is a Reason I Tune at the Drag Strip!!! Course, I have No Intentions of Expressways nor Bonneville!!!
Edit; Forgot to add...Wobble is also caused by the Tracking of the front vs rear wheel...certainly if the Rear is "aimed" to one side or the other...BTDT, Scary **** at 135+...and the Shut down approaches!!! Laying in the Tank will Not cure it... but, sitting up, will exacerbate it!!! Lightens the front end!!!

 

Yeah I agree with some of that, I definitely need to check my alignment again cuz it seems to be more prevalent on right hand sweeps than left hand sweeps.. It tends to go away on left hand sweeps. As for messing with the rake and trail yeah that does contribute as well.. Currently I'm at 4.8 in of trail where it used to be 6.2 for the fat boy.. And as we all know decreased trail decreases stability at speed..

 

In My World...4.8 ain't enough!!!!

 

True but it all depends on what you're looking for or your necessities.. I like the fact that I have major improved handling in the twisties.. For a Fatboy it's pretty nimble

 

The English Bloke.


I saw this a couple of years ago so I knew exactly what you were talking about.

 

Thank you, That was the one ...

 

In the world of large trucks Navistar started having death wobble issues with a newly design class 8. Truck was built with a lighter front axle and overall weight for fuel economy, Navistar engineering put a more restrictive pivot bearing on the drivers side of the steering axle and gone.

I know you just put it together but trying to relate our steering issues to neck bearing adjustments on a bike, may need to tighten up the neck bearing since it's not a factory design no more. Navistar used a setting that has worked for years but the newly designed truck sent them back to the drawing board.

 

I always did have my fall off tight but recently I noticed a solid knock over small quick bumps.. Possibly indication it's loose again.. Will check in a few days.. Working overtime the next few days..
I'm also thinking the weight transfer to the rear by going 2" over on the front end might have something to do with it as well...