oops...wrong thread... response removed

 

I am running a Michelin rear and a Dunlop front. There is no wobble.

You can create a cup in the front tire from an imbalance in the front suspension, a warped rim, or a manufacturing defect. The cup can get worse faster if you run the wrong inflation pressure, too.

Time to take it to someone that puts the front up in the air and checks the fall away, the wheel true, the bearing condition (neck and axle), the wheel balance, and the spokes front AND rear (if you have them). Also the alignment of the rear wheel... if you don't feel competent in doing this.

 

I replaced the front tire a few weeks ago. The wobbly problem is pretty much gone. Except at around 40-45 mph, it feels like the bike is bouncing. Took it to the shop where the tires were put on, and they checked the balancing, spokes, belt. All good. They rode it and didn't feel anything. I call BS. But I really don't know what would be causing the bounce. It's not really in the front or rear, but rather the whole bike. could it be shocks?

 

Bouncing-are you lugging in 4th gear? lol. Need a better description of symptom please. Where it seems to be coming from in regards to the bike and description of the symptom.

 

this is a very timely thread for me. 6 weeks ago bought new to me '08 Deluxe with 18K miles on it. Fairly early on (within the first couple hundred miles) I noticed bar shake/wobble. Not really bad, but under prolonged hands-off-bars deceleration it would get bad enough that I'd grab the bars before riding it out. It is most pronounced at 40 mph, it goes away over 45 and under 35. It also seems to be worse in 4th gear than third (see comments regarding lugging in 4th below). With hands firmly on the bars, the bars don't shake, but I also feel a bouncing - feels like ONLY the front end to me - best way I can describe it is poor rebound damping in the shocks...it's got a regular frequency to it. I have to this point interpreted it as the reaction to me dampening out the bar shake by holding on - that energy has to go somewhere, so I guess it goes into the suspension.

The best way for me to initiate the condition is on a gentle downhill, go 45 MPH and roll off the throttle and take hands off bars. The bar shake amplifies pretty well as it decelerates through 40 - the downhill seems to increase the issue because it spends more time though the 40 mph band. Doing this gets it to the 'scary' point and I'll grab it before I ride it out. On level ground, I usually lose speed quickly enough that it doesn't have time to get 'scary' before it smooths out again at 35.

I've also noted what feels like the front end, for lack of a better term, gently wanting to 'step out' during 40 mph sweepers (think highway cloverleaf on ramp). Not bad, but enough to notice it. Not sure if it's related, but thinking it might be.

Both the front end bounce and the 'step out' tendency happen under steady constant throttle - no deceleration required to get these effects. Haven't tried hands free in neutral at 40 to see if it will do the shake without engine braking. Now I have an experiment to try tomorrow.

I'm curious what your thoughts are on the reason behind lugging causing the shake? Higher levels of engine braking at VERY low RPM causing on/off pulsing of drag to the rear wheel? Or same effect through differential tensioning/loosening of the drive belt between compression and exhaust strokes? Since the drag is happening off-centerline (from the drive side) that is pulling the bike momentarily out of alignment??

First thing I did after feeling the shake was check tire pressure. Front is kept spot on spec at 36psi, and I run the rear at 38 psi (compromise between solo and 2-up, I'm a bigger guy anyway, and I'm more comfortable with that for short 2-up hops with the wife. Goes up to 40 if we're going any significant distance 2-up)

It's going back to the dealer (under 60 day warranty) for the second time tomorrow for this. First time they trued the front wheel (was in spec but close to tolerance - .36 IIRC, trued to .11). I am also getting some gentle pulsing from the front brake at very low speed under light brake application - they checked front rotor runout, in spec at .08 I think it was. That was all they put on the service ticket. On my call to the service manager to set up appointment number 2, he said they also checked head bearings and fall-away. I haven't noticed any unusual front tire wear, and they didn't mention front tire as a potential issue the first time. Would the truing process also include balancing the front wheel?

Can anyone point me to a good guide for checking rear wheel alignment myself? Was easy to do a quick check on the sporty, but I'm not sure how to do the 'same measurement from the dot to axle centerline on both sides' without a single swingarm with the dot...

Thanks, and sorry for the wall of text...


Dan

 

You described a lot better than I did!
I notice it most using a steady throttle or going downhill, not lugging in 4th, around 40-45 mph. I also have some drag in my rear brakes, but I was told that was because after putting a new rear tire on, the pads are in a slightly different location and are wearing differently. I would think that by now, that would be gone.

Please do let us know what the dealer finds. I hate the service department at my local dealer, so it's kind of a drive to visit the dealer that I do like. But that might be my next step while I still have warranty.

 

Check the neck bearings adjust and lube

 

Had the wobbles a while back, would always happen at highway speed...for me, it was a bad front tire. Sucker started to disintegrate...was the weirdest thing. It was a quality tire...the company replaced it, no charge, and have been wobble free ever since.

 

Just a minor update on my wobble issue...

On the way to the dealer yesterday had a chance to see how it behaved hands off in neutral. The wobble DID start, about the same as it normally does, but it did not seem to get progressively worse. Due to traffic and the short ride to the dealer, I didn't get a chance to try it a bunch of times to see if that behavior was consistent. But based on this test, my guess is that there is something causing a minor wobble that gets amplified by the off-centerline forces during deceleration.

Dealer service manager seemed rather reticent - kept giving me the line about "Harley won't do anything if the wobble only happens when hands off bars." I repeatedly told him the wobble is happening hands on but can be damped out by holding on - can definitely feel it with light grip on the bars. Hoping for the best, but don't have a whole lot of faith. Going to try to get a list of all the stuff they checked when it's done...

 

Could also be a bad rear shock or broken front fork spring .