Swingarm Attachement

[Mayday53]

My mechanic and I are trying to reinstall the swing arm on my 53 K model. However, despite the bolt being removed during deconstruction, now we cannot slide it back through the swing arm bearings. It simply does not fit and we know it is the same bolt since it was placed in a labeled bag. So I am totally confused...actually dumbfounded. We ordered a whole new swingarm bolt/bearing assembly kit today, it was only $83 so I figured what the heck.

Question 1: does that bolt and bearing assembly need to be machine pressed into the frame?

QUestion 2: Any techniques for installing it?

[EKHKHK56]

Hello. IF I remember right...the assembly needs to have the preload backed off a little. No pressing needed. Loosen preload, assemble, than retighten bearing nut to preload bearings one foot pound. Hope this helps. Erik K

[hennesse]

I did mine recently by myself, and found it to be a real pain. The bolt has to slide through the bearing and inner spacer, through the frame holes, then through the other side inner spacer and bearing. The bolt and the other parts are an exact fit, so getting them all aligned so the bolt slides through is a little tough. Wiggle!

If you can get the bolt through all the parts with the swingarm off, you should be able to get it through with the swingarm on. Wiggle!

[Mayday53]

thanks hennesse. Unfortunately, the bolt will NOT go through the bearing and it is really making me wonder if we,somehow, got the wrong bolt. It seems unlikely, but the proof is that the dang thing will not go through either bearing or the spacers. We did order a new kit, as I mentioned, so we will see how that compares when we get it in a couple days. This has been a LONG, LONG refurb on this bike (2 years) and I am anxious to get it on the road this summer for the first time in decades...wish me luck!

[sportsterpaul]

If the bolt fits in the frame-- its a slip-fit, no pressing or tapping required, then you might have Taiwan bearing with a mm inner bore. Its like the batteries you get with the terminals backwards, that the website assures are a "perfect fit". Are the bearings new, or the same one you took out?

If meticulously cleaned bolt does not slip into the surgically clean frame, maybe with a little Tri-Flow, then somebody dropped the bolt and put a ding in it, or someone used it as a drift to pound out the pin on the hydraulic cylinder of a D9 CAT. To test this theory-- look at the threads-- if they are all smushed and the goofy nut does not spin on finger-loose, well, good thing you bought the new bolt.

I had a brutal time getting a bolt out of a 1979 frame, the slide hammer did the trick. But once it was out, cleaning everything and some 600-grit on the bolt to show any dings or high spots, and it slipped in, helped by a liberal application of PermaTex anti-seize from the tube. The pot/brush anti-seize bottle gets dirt in it, and that just gets you back to seized components.

The bearing should be "real" xxTimkinxx Timken bearings, not aftermarket "close enough" made on metric machines.

[hennesse]

The bearing should be "real" Timkin [sic] bearings, not aftermarket "close enough" made on metric machines.

Yeah, I used Timken bearing #17580 and Race #17520 - from BSC 231-853-5522 E-mail: [email protected]. Original Equipment Timkens are pricey, but should last another 50 years or so.

Dave

[sportsterpaul]

Yeah, I agree Timken bearings are worth the price. Not so sure about 50 years-- depends if you over-tighten them. I was complaining to racer Vance Breese about how involved the procedure was. Take off the shocks and everything else, tighten the spanner nut until-- what is it-- something like 6 pounds or 9 pounds drag? Vance laughed and said the only way to get an iron Sportster to handle is to find the biggest cheater bar in the shop and tighten the bearing spanner as tight as you can. I pointed out this would egg out the rollers and leave little divets in the outer race, so called "Brinelling". I found this in a few of the bikes I have taken apart. Vance's attitude was "So what's your point?" In other words, he saw those bearings a frequently-replaceable component. What he was trying to fight was the rear swing arm loading and unloading as the chain pulled on the rear sprocket. He pointed out some racers would even stay on the throttle a bit as they were on maximum brake, since staying on the throttle kept the swing arm pulled to the right by the constant chain tension. He said some guys would get into trouble since if they let off the throttle completely, the swing arm would relax to a neutral position, or worse yet, get pulled left by the 79-and-later disk brake. Then the bike would get squirrly when you got back on the throttle coming out of the turn, since then the swing arm is getting pulled to the right by the chain again.

After that I became a lot less diligent about the assembly procedure. I even own the Chatillion scales needed to pull up on the swingarm and get that drag measurement. Now I just grab the swing arm and tighten until I feel a little resistance to up and down motion. I don't want to dent those races right away, but I don't want a loose swing arm that acts flaky when I power out of a turn.

[Mayday53]

SP,

Yes the bearings are original, so is the bolt, we thought, based on the way it was bagged after extraction. Good thought on the 600 grit cleaning and threads. Interestingly, the nut would not fit on the bolt properly, so we are at a pint where we figure we must have just flippin got it wrong somehow...at this point I do not care how since we have the new parts.

Follow up question: Is there a recommended torque setting for the nut on the swing arm bolt? I had one guy recommend we drill and cotter pin it after assembly...thoughts/tips?

[mikeslemmon]

100 ftlbs on the big nut is kr xlr spec