Hi all, been quite awhile since I've posted anything here. Now that winter is in full swing I've decided to tackle a project I've been meaning to do for some time, strengthening my swingarm on my 1988 FLHS. Yeah, I could have gone the swap to later route but I wanted to keep my custom wheels and besides, I needed a project. I was going to replace the cleave blocks with a spherical bearing kit but before I removed the swingarm I fitted up an under brace to give the arm a bit more stiffness. This is an old school way of bracing the swingarm, the first time I did this was to my Suzuki road race bike back in the early 80's and I knew it worked. This bracing in combination with the spherical bearing kit and using the swingarm axle and mounts from the Glide Pro kit I already have installed should help stabilize the handling some. Next is to finish out any surface imperfections and then off to powder coating.

Old reliable, 88 FLHS

Braced swingarm

 

Right on! Nice work. Nice bike too.
I’m at a similar point with my FLHR - the swingarm’s off for inspection (it’s a new bike to me) but I’m leaving the like new OEM Cleve blocks and outer bushings as is for now. I might go for Glide Pro outer bushes later if I notice wobbly performance, which I haven’t yet.

What front brakes are you running? I assume you have an aftermarket master cyl as well?

Carry on.
Cheers!

 

Thanks! I'm running PM 6 piston differential bore front calipers with EBC floating rotors and a PM matched master cylinder. My bike has had a weave issue forever, I've tried the Glide Pro stuff, as well as making my own 3rd link stabilizer for the trans to frame. It all helped but the swingarm really needed stiffening, IMO. I've managed to firm up the front end with Race Tech emulators and springs which really helped too and am running Drag adjustable shocks on the back. I've been told I ride the bike too hard and it wasn't meant for that type of riding. Well, I say bs, what's too hard?

 

Nice looking bike!
Ditching the weave blocks will get most of that wag out, the swingarm mod looks good, did you relocate the oil filter?

I went with the 02+ swingarm, but the spherical bearing conversion is what I think helped most, also went with new oem rear mounts with Sta-bo bushings stuffed in them.
I didn't even feel the need for a third link stabilizer, I can roll up with it like it is now.

They're right, the bike wasn't meant to ride hard the way it came stock, but it's not stock,,, so

 

Didn't need to relocate the oil filter, everything fits with plenty of clearance. While fitting all the pieces I made sure to cycle the swingarm through it's complete range of movement ( based on the amount of travel in the shocks ) so it clears the belt and frame.

 

" Weave blocks " hahahaha

 

May help to stiffen up the swing arm, but does not solve the cracking problem to begin with (and worsened with the swing arm stiffer now as well).


So would have started with steel plates top and bottom to reinforce the axle windows part of the swing arm to start with, the would have welded in the stiffer after that.


Also, ditch the OEM stock axle blocks that go into the swing arm for the the axle to go through, and go to something more beefier to help prevent the stress point cracking as well.


Also, don't be in such a rush to stiffen the swing arm, since its the lesser of the problems in the end on a touring bike dam near 1K in weight
Hence front and the top of motor to frame couplings that wear out quickly since they are the hold points for the drive line to begin with, flex in the forks, and even a bit of frame flex as well. Simply, HD has all this flex in the bike, to lesson the amount of vibration that is translated to the rider in the end from the motor.

In the twin cam and up, HD went to counter-balancers in the motor to lessen some of the motor vibration, but this brought on its own problems, including the motor having more chain it it than a 10 speed in the end.

 

Nice. Did you have to build a jig to bolt it into to prevent the possibility of warping or were you able to just clamp it to a welding table?

 

Had that happen on my 01 Road King. Ended up upgrading it to a 02+ swing arm. Pricey but provided peace of mind.

 

Looks to me like the tube welded under the axle window will do a fair job of reinforcing the place that sometimes cracks.
Maybe weld a plate on top also.

When I still had that swingarm, I made washers with a diameter a little larger than the swingarm sides, made one for the inside also, just had to shorten the spacer the width of the washer, inside washer was aluminum and about 1/4" thick, outside washer was stainless and as thick as I could use and still get the pin through the castle nut.

Those aftermarket adjusters won't fill the inside of the swingarm enough to help stop cracking because the shock mount will let them slide in, The important thing is that the adjusters are close to the same width as the inside of the swingarm tubes to prevent crushing the swingarm when the stack up is tightened, the large washers stop the damage to the axle widow area.