My one modern bike is a 2009 Harley FXDF Fat Bob. I'm not your classic "Harley Guy" and never owned one prior to this bike. I guess I just never saw one that really appealed to me. While on vacation in VA Beach in 2008 we were stopped at a light and a guy pulled up next to us on a flat black Fat Bob, and I was hooked. I thought about it, talked about it, procrastinated and probably would have put it off for a while, but my wife went and got me one as a birthday gift. Some wife, huh?
It's a great bike, fun to ride and nice to have as part of the stable. However, I really don't like the front suspension - its way to soft and bouncy for me, and I'm not a big guy at 170 without gear. When my bike recently developed the dreaded Dyna "clunk," I decided it was time for a few changes.
If you poke around a bit you'll find that there are many reasons that Dyna's clunk. You'll also see this described as a rattle, shudder, vibration, and general front end noise. The Harley forums offer a lot of advice and possible cures. Some older bikes actually need a stem washer upgrade, but mine isn't one of those. Other causes can be the top stem nut not torqued correctly, the fall away set incorrectly, loose tank bolts, and too light grade oil in the forks.
I figured I'd kill two birds with one stone and fix my clunking and do a little fork upgrade at the same time. After doing a little research I ordered a set of 49mm Ricor Intimidators to help with the stock valving, got a couple quarts of Amsoil Suspension therapy 10W shock fluid, and yesterday set to work to get everything sorted out.
Getting the forks off the bike is basically the same as any other bike. Remove the front wheel and fender, get the brake calipers out of the way and loosen the pinch bolts. I loosened the top nuts on the forks while they were still in the clamps, as I don't have any clamps floating around to easily do it once they're off the bike.
My 13 year old son Sean gave me a hand with the forks and the rest of the job. Having a second set of hands around made it much easier to pop the top caps off once the forks were off the bike - I had him push down on the rag I had covering the nut while I undid them the rest of the way. Once apart, I showed him the spacers, the springs, and explained how to drain the fork oil, cycling the forks a bunch of times to get as much as we could out.
The stock Harley oil was not too bad looking- a bit dirty but I expected that (this bike has about 10,000 miles) and a little on the thin side. We cut the spacers about 1/2 inch each to match the space the intimidators would be taking up in the bottom of the tubes. Once done we measured out the new fork oil (26.4 ounces per leg) and started the reassembly. I added about half the oil, cycled the forks a bunch of times to get the air out, then added the intimidators and the rest of the oil. After measuring each leg to get them correct and the same, we dropped the springs back in and got the top caps back on. Here again another set of hands is a huge help. The first one went back together easily, but we struggled a little with the second one. Sean came up with the idea of having him turn the fork tube while I held the nut down, and that worked like a charm. Again, we used the triples to hold the forks so I could torque the tops down. End to end this job took us less than 3 hours, and that was taking our time with a break or two mixed in.
Once everything was back on the bike I checked the fall away. The HD service manual describes their procedure, but it's a little too much for me. I could tell right away it was way loose, so I loosened the top nut and the top pinch bolts, and found a long screwdriver to use to tighten the star nut.
All that being done, I fired up the bike and took it around the town for a bit. What a difference! The dreaded clunk is now history, the bike feels tight again, and the front suspension is much improved. I'll have to get some more miles on it this week before I get too crazy raving about it, but I am much happier with forks now. I attribute all the noise I was hearing to the fall away adjustment being off; I'm going to keep a closer eye on that in the future. I'm sure the neck bearings are now well settled and I doubt I'll have to do that again, but the entire procedure took about 10 minutes so it's not a big deal.
Ride smart!
Good article thank you
ReplyDeleteThanks for the info. My 14 Fat Bob is making the same noise and my steering is quirky. I imagine going to HD for the maintenance will be too expensive.
ReplyDeleteThanks for the info. My 14 Fat Bob is making the same noise and my steering is quirky. I imagine going to HD for the maintenance will be too expensive.
ReplyDeletegot that on my 2014 too. needs new oil and the upgrade sounds like a good deal
ReplyDelete