Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Chief]

Has anyone ever experienced a non-planar, or not flat, swingarm?

What am I talking about? When I was installing the Progressive shocks on the bike, both shocks would not bolt up at the same time. At first I thought the shocks were of differing lengths, about 3/16". I measured both of them and they are the same. I didn't bother with it, and found a way to bolt them on.

Enter the Bitubo's. Same problem. When bolting on the shocks, with all of the weight off of the rear wheel, when the left shock is bolted on, the space between the lower and upper shock bolt holes, on the right side, is longer than the holes in the shock. If I did the right shock first, then the holes on the left side are too closely spaced making the left shock appear too long. My process is to bolt the left shock on and then lower the bike some until the weight on the rear wheel compresses the left shock enough so the right shock bolts up. I then use different amounts of spring pre-load, left and right, to offset the difference in shock compression.

Assuming the top of the motor is not cranked over to the right and skewing the swingarm, has anyone ever come across a swingarm that is out of wack? My thought is that if I were to lay the swingarm on the table, it would only touch in three places, and rock like a chair with a short leg. Or, could it be the upper shock mounts on the rear frame tubes are out of wack?

Has anyone ever seen anything like this?

[hogasm]

Re installed the 440's last night and found the exact same situation you are describing. My buddy at Harley said that no frame is perfect and that most frames on the left side are longer than the right side.

[Chief]

Re installed the 440's last night and found the exact same situation you are describing. My buddy at Harley said that no frame is perfect and that most frames on the left side are longer than the right side.

Well, there ya go. I got home today and started pulling off parts so I could establish some good reference points, and my initial assessment of 3/16" was a bit off. The true measurement is right at 1/8" I'm pretty sure that would fall into manufacturing tolerances, so back together she goes.

[SPIDERMAN]

Chief,
        The first thing I'd do is verify that both shocks are the same length bolt hole to bolt hole. Doesn't take much on the adjusters one to be a bit different. If the shocks are 100% the same, then check the top motor mount. It would not be unusual for the top motor mount to be off. I've adjusted a fair share of them on FXR's in my day. Best way to deal with this is to get the bike on a lift and take a magnetic plumbers level and hold it against the front fork tubes to check plumb. Once you're sure the bike is plumb check the motor for plumb. You can do this by removing your derby cover and putting the level across the opening vertically. If the motor is out of plumb then loosen the locking nut on the rods on the top motor mount and adjust it till you're plumb and retighten the locking nuts. At this point, your swingarm should be level. If it's not then I'd check the mounts on the sides in the front for wear. There is a big hard rubber donut almost like a hockey puck on the end of each side of the swingarm. There is a small dowel pin the holds that in the correct position and then it is all more or less a compression fitting on the end of the swingarm with the clevis blocks being the vise. Beyond that, it's possible for your swingarm to have a twist in it that was never taken out when the welds were stress relieved or maybe happened if the bike was dropped at any point. And I don't mean skidding down the pavement sparks flying road rash dropped, it can be as simple as the bike going over on it's side. The best way to tell if you're swingarm is out of whack is to have a buddy ride behind you and sight down the side of your bike to see if he can notice any crabbing. That's about it for me on this subject.

B B

[DW6019]

Of the five (FLH type bikes) that I have put shocks on, they are all shorter on one side. Nothing to explode over. Just about 1/8 to 3/16. Doesn't hurt anything. Mine is that way and it tracks very straight.