I have a 96 Heritage
At mid range speeds 30 to 50 mph the front end starts to shimmy, over 50 it seems to smooth right out ( so I try to keep it around 90, lol) When I put on a new front tire it went away for about 500 miles, then came back. its 5000 miles later and I put a new tire on again it went away but this time 280 and the shimmy is back.
Does anyone have any idea what could be going on, any info would be greatly appreciated.

 

I would say that I'm pretty sure it's loose steering head bearings, that need to be tightened. That's where I would start first. If you don't have a service manual, do a search on these forums and you'll probably find the procedure to tighten them, . Keep us posted on what you find.


Good luck
John TN

 

Here's a simplified neck bearing check & adjustment procedure. You also should check the front wheel bearing end play.

Jack the front end of the bike off the ground. Tighten the adjusting nut until the front end is hard to turn. Next turn the handlebars back and forth, from stop to stop, through several cycles. Notice the front end becomes easier to turn. Back off the adjusting nut to a slightly loose fit, then tighten to about 9 ft-lbs torque. If the front end still wobbles after this (tire pressure good and tire in good condition, with no cupping, etc.) and the wobble occurs during deceleration, tighten the adjusting nut a bit more.

If you get a shimmy and more tightening does nothing to help, then suspect that the steering head bearings have shifted and the races are no longer parallel to the axis of the steering head. This is not unusual in HD bikes as they are relatively heavy. Modern bike head bearings tend to shift back and forth in the frame, especially on the heavier bikes, and this causes the bearings to become non-parallel. Any free play in the head bearings will compound this situation. This sets up torque forces that constantly try to correct themselves resulting in a shimmy, or head shake. The cause is not looseness; the bearings have shifted, and things ain't parallel. Pull the front end off and try to reseat the races in the frame neck.

Check the head bearings frequently IAW the service manual. Since these bearings do not move around like those on an axle, they tend to stay in one spot in relation to the race. Therefore every blow on the front end from road conditions tends to flatten the individual rollers or ***** ever so slightly. Over a period of time these flat spots can cause a condition whereby you point the forks straight ahead, and they tend to fall back onto the flat spot, causing a weave as you go down the road. If tightening the preload does nothing to correct the situation, suspect flat spots in the neck bearings.

Alpha Samuel (from MSN Harley Tech Tip Message Board)

I had a similar problem to yours on my '87. It just about dumped me once, and shook so badly that it loosened the bolts holding the risers to the triple tree. I ended replacing the tire, wheel bearings, adjusted the endplay to spec, replaced the neck bearing cups, neck bearings, and adjusted them as described above. I also drilled and tapped the neck post for a grease fitting to shoot some lube into the neck bearings on a regular basis. My final adjustment on the neck bearings was a bit tighter than above, almost 15 ft-lbs. It handles as good as can be expected for a big ol' HD Sloptail.

 

thank you for the heads up so to speak, i was thinking it could be the system was loose but not sure . i just didn't want to start work that is not necessary, but now sounds unaviodable
I will keep this updated to my progress

 

Well said Skip,

I too like mine just a tad on the tight side. It's amazing at the number of bikes that are running around with loose bearings and this can cause you to crash, even at slow speeds and as you described. I usually every ride when going slow (30 mph or so) lift both hands off the bars to see if I'm getting any shimmy at all, and if I do it's tighten time.

John TN

 

great info skip!

 

Great info,

This is only one of the many reasons i will be doing service like recommended in my manual.


David

 

Thanks
It was the head bearings. I did the test according to the manual; put the bike on the lift took off the break and accelerator cables, the windscreen and the wind deflectors. Put masking tape on the fender hung a plumb bob over a centerline on the fender.
There was a 1/4 of an inch to the right and a 1/2 inch to the left. Therefore, I tightened up the bearings and they tried to lock up with very little adjustment. Therefore, I just swapped out the bearing. Now when I let go of the bars it stays straight and smooth. I thank you all for your input.
Now I need to do the same to my Softail.
I also think that this winter it will be time to replace all the bearings. On the heritage