So I'm running a narrowglide with 21" wheel and Avon ribbed front tire on my 77 FXE - I've wound it out pretty far on the highway and it is very straight - stable in a straight line - can ride the bike no-hands and it tracks straight-smooth - HOWEVER - on sweeping turns on the highway - when I hit bumps - the bike tends to wiggle a bit - feels like the bike is flexing - it corrects quickly - does not wobble - but seems to feel a bit unstable - since I have mainly ridden ironheads - and I have not experienced this before - I'm wondering if this is normal for shovelheads running skinny tires/narrow fronts??????? Obviously, I would to avoid a 65MPH tank slapper and massive head trauma as I flip-flop across traffic in the morning at rush hour - ferg

 

Check swingarm bearings

 

More common is the swing arm shaft pitting out were the bearings ride, just takes a hair and the *** end will be all over the road. Uneven fork oil levels or a bad shock on one side will make her squirrely too. Isn't the 21 I've been running them decades now.

 

a rusty neck bearing that has become tight

the fork tubes being misaligned to the front wheel

lower tree bolts loose for the tubes

a broken inner spring < you need to look at everything before you ride it again

 

TwiZty I think you nail it for me here!

Been fighting the wobble issue for a bit. Then last night visiting the bike in
the garage for a little one on one quite time after work I did find moisture
coming out of the right front shock ...Sigh, yet glad to hopefully end this.

 

It would have to have been putting out oil for a long time to get a wobble, I'd check the swing arm bolt it's the most common wiggle problem I've found on the older ones. Have somebody follow you and watch the rear tire, if the bolt or the swing arm bearing are roached they'll see it moving around on you it's that obvious.

Rear wheel bearings going out will act like that too.. Check them.

 

I had a lil jammer hard tail with a 103" engine and a 19" front and rear tire


@ 147mph when I let off it would wobble - then I learned not to just shut the throttle and I slowed easy like -- got smart and installed a steering dampner


then like a dumb *** I decided to look back one time to see what happened to the guy on the Kawasaki - man talk about a bike change lanes when the wind grabbed my helmet -


but no serious these guys have some great answers..

 

Just throwing it out there but my Shovel does the same thing when my front tire pressure is low. I have a slow leak so I check often but sometimes I forget. I have a friend that has an 09 Dyna that was doing the same thing. Same problem low front tire pressure.

 

check for loose rear spokes....if you have them.

 

+1 regarding some good advice given here...

I recently chased a high speed wobble occurring at 70 mph in highway corners (1982 FLHC). I went through the process of elimination starting with the front end: Adjusted fall-away, new neck bearings, new progressive front fork springs, checked all spokes and decided on a new stainless steel spoke wheel complete with bearings. I finished up the front-end overhaul with a GMA front brake caliper and Russell rotor. Lastly, to be thorough, I added a new Dunlop.

It still wobbled. So, on to the rear: New swing arm bushings, new shocks, and while truing the alignment, I noticed some lateral play at the flanged axle spacer (OEM 43602-78A). That part was the source of the wobble. Again, to be efficient, I purchased another new stainless steel spoke wheel complete with bearings and internals. Money well spent, as riding now is safe and steady at all speeds.

So it’s accurate to say that the rear wheel can also initiate a serious wobble felt in the front end. Hope this helps.