Share any thoughts please!

So I get this low speed mild tank slap a few weeks ago, thought I might have hit that pothole/whoop at an odd angle, didn't think about it. Rode a week or so later & after I rolled off throttle and it happened again. I then set about zeroing in on when & how it does it to learn what's going on. Here's the weird part, it is far less determined by speed then it is RPM. It happens only when I roll off the throttle and the RPM's drop to the low 2K range, say about 23/2400 down to about 1900, regardless of gear. Picture yourself casually coming to a stop light using engine decel only right before you pull in the clutch. To test it I merely remove my hands slightly from the grips to allow the bars to start to wiggle enough where I can say "yes, this is indeed a tank slapper" without concerns of losing control.

Needless to say I have to wonder WTF is causing that?

Then I start to ponder if any mildly odd sounds or feelings during past rides might be indicative of the origin of the problem. No odd sounds, cool. But I'll share this. I normally ride solo 99% of the time. My girl received a mild foot injury from a cager accident (couldn't ride her bike) so I slapped on my detachable Ultra TourPak (TP & mounts are secure) after finally ordering a missing antenna cable to take her with me. Get's a little interesting. In the past, on those rare 2-up rides with her I'd notice a faint amount of extra vibration when using the rear brake during moderate-to-heavier braking below 20-30 MPH. Couldn't detect at higher speeds. Absolutely nothing has changed except that now I have the TourPak on, but now I can feel the engine vibration through the brake pedal a lot more than I ever did before. The brake pedal is not touching the heat shield in any way, but I would describe the feeling of the brake pedal (and bike vibrating more) as if it were touching. Very strange.
My girl is something like 120 pounds, so that surely isn't a factor. The TourPak weighs squat, so that can't be it. Wheel nuts/axle are tight, tire pressure is spot on, brakes aren't dragging, belt is at correct tension (I have the tool). Bike is an '09 Roadie with maybe 10K or so on the clock and maybe 2K on the tires, which aren't cupping BTW.

Sorry so lengthy, simply put, WTF is up with my Roadie? Any thoughts?

Thanks for any and all!!

 

Check front tire pressure. If its low speed it's gotta be in the front during weight transfer. Tire, tire pressure and neck bearing/adjustment. Something is out of round or balance in the front.

 

remember that there has been a spec change for the fall away test.

mike

 

Check your neck bearing for excess slack. Tighten it up if it feels sloppy. There are test guides in your manual.
Check for bolt security in your front forks right up to the trees & with the front tire off the ground, look for lateral movement in your front wheel bearing.
Although this is a remote possibility, check your frame from the gas tank down under the motor & transmission for cracks.
Have you ever checked the fluid levels in your front forks? If not, drain them out & replace the oil using an accurate measuring system like a large siringe that has cc's as a measuring scale. this is also in your manual.
On a heavy bike like a RK or FLH, going to progressives isn't a bad idea!
Keep us posted!
Hatch.

 

What is the condition of your front suspension? Have you ever had the forks apart for mods or just to varify proper flud levels? I would recommend pulling the forks and just freshen up the fluid if nothing else, only had 5k on mine first time I got into the forks, and they had uneven fluid levels and one tube was full of rust. It definately influenced better handling. Check the neck bearings, front motor mounts, rear isolators, rear shocks, rotors, calipers, and wheel bearings. Check it all until you find it, your life is riding on it.

 

Already mentioned the tire pressure is spot on, for both tires. My thoughts lean near yours regarding front end for reasons you mentioned, Thatzmister2u. Note; when I say "low speed" I'm comparing mine to the common complaint riders had near the 80 mph range where mine will happen at 50, 40, 30, and even as low as 20 mph with the only thing in common is the RPM's at which the tank slap will start. It's always the same RPM range. Strange.

mkguitar, true. but..............

but............to both because here's the part I can't wrap my brain around. Why would it be, quite literally, immediately after I through the TP on the bike?
I say that because my bike handled perfectly fine right up to and including shortly after my girl's foot issue. We rode quite a distance over a few rides before she got fed up with not having anything to lean against. That's the whole reason I through the TP on with antenna's hooked up only, no speaker or lighting wiring yet.
Then, no kidding, immediately after the TP was on the bike this tank slapping crap started. Oddly with or without her on the bike.

Cool part is, with the thoughts from you guys here on the Forum, I'm less likely to overlook something and may likely look closer at other items.
A real help, and appreciated.

My office is closed on monday so I plan on re-torquing all the obvious items just to be sure once again.

 

Check the fall away. A good amount of the RG are having this issue and specs for the fall away have changed to be tighter to correct the problem.

Search the forum for it, there were a couple threads about Road Glide wobble etc after adding the tour pak and for other reasons

https://www.hdforums.com/forum/touri...nd-wobble.html

 

Even though its relatively light, the TP slightly changes the balance and weight distribution on the chassis. Ever had a chassis alignment, does the bike track straight if you let go of the bars? Just start eliminating all the possibilities, the fault will turn up.

 

Like hatch said check the headset for excessive slop and make sure front tire is aligned with the rear. It' easy to do just wet water both front and rear tires and roll the bike a head in a straight line on a dry concrete. checking to see the rear tracks in the same line as the front. Not like a Mexican low rider going down the freeway at a skewed. You can also use a string line or a straight edge watching for all four sides of the rims should touch at the same time in a straight line. thirty years ago we took a tape and measured from the swing arm pivot bolt center to the rear axle bolt center. Never trust the notches on the swing arm for belt or chain adjustments.

 

Damn, the link to that thread was truly helpful! As long as I've had my bike I had no idea it was "that" common amongst Roadie owners. Added some extra oomph to the points shared here. Thanks for that.

hatchetman & fabrik8r, chrome lowers during 1K service, part of the deal at time of purchase, future plans are for RaceTech set-up for forks but up 'til now had zero issues, gonna hit each possibility to ferret it out. Common thought is strong on the neck bearing adjustment. Sucky part is, if I remember correctly the proper way to adjust the swing-away is to remove all the crap from the front end (cables, and whatnot) to remove any influences. Time being so limited these days will mean it'll be as-I-can-get-back-to-it length of repairs. Gotta do it of course. Oh, she has always tracked straight FWIW. Going to check mounts and frame thoroughly as well.

For now I'll sign off for the evening, but gotta give huge thanks for the right direction you guys pointed me in already. I'll check back before I dig into it over the weekend and I'll follow up after I (hopefully) figure it out.

Thanks again, Good night gents.