wobble at slow speeds

[MexiCan]

Hi everyone. I wonder if anyone has encountered a slow speed wobble on their MK1. Mine is a 2012 model with 55K km and new tires. The dealer suggested a change of the steering bearing which was done after a 3K Km trip on the new tires. After the bearing was replaced, I immediately noted an instability in the bike's handling, similar to what someone posted here at highway speeds. Basically, there is a slow oscillation of the bike (1Hz or less) most noticeable between 40-60 Km/hr and decelerating or keeping such speed steady. However, I also noted a tendency for the bike to fail to track steadily at speed on moderate radius turns or on/off ramp. The sensation is similar to that described in the high speed wobble: as is following a large truck and being mildly buffeted by the turbulence, or as if riding on a surface with tar "snakes".
This bike is rare in these parts and looking at the usual part suppliers, you can't even find the bike in order to search for compatibility. The invoice from the dealer indicates a part 237221020, fit for a CB600F/VT600.
I have been twice back to the dealer. They say they have tightened everything, checked the rear wheel axel alignment and tire pressure/balance. The mechanic initially acknowledged some degree of wobble but seemed to be giving me the benefit of the doubt.
I have had this bike almost since it was new and travelled/commuted everywhere with it. It is just not the securely planted bike it was prior to the bearing job.
Any thoughts? Is the part wrong for the bike?
Thanks in advance.

[pedro]

So, you could check the wheels are balanced properly. Then check they are aligned properly. Next, check the forks work as they should. Then I'd have a look at the effectiveness of the rear suspension. I don't suppose you've dropped the bike any time? Just thinking the frame might be a little bent. Hopefully not and indeed probably not. I'd also check all the engine to frame bolts.

But I think, from what you say, the steering bearing is what seemed to start the wobble, so that, for me would be my first port of call. You can't assume because it was done by a mechanic in a dealership that it's good. They are fallible. Only then would I look at the other stuff.

[MexiCan]

Thanks Pedro. No, the bike has not been dropped and the alignment seems fine. As you said, the main change in the bike prior to this issue is the bearing replacement. I suspect they put the wrong part in. Is there a resource where I could check the compatibility of the bearing kit they used?

[Art]

With Honda steering head bearings its almost one size fits all, for your reassurance check out Hunters of Newcastle upon Tyne they list the 22 1020 tapered roller steering bearings and seals kit by All Balls as suitable for CB600F, VT600, all CBF1000 models 2006-2016 and many many more Honda models.

If you’re allowed spanners check the tyres, wheels and headstock bearing as per pages 4/32, 14/13, 15/6 and 14/30 of the workshop manual. If you haven't already, you may want to download the Honda Workshop and Owners Manuals here.

[MexiCan]

Thank you Art. I will check but your information is reassuring (in terms of the part)

[Rev Ken]

MOST Biffers have some sort of wobble at low speeds even when perfectly set up. It varies in severity for riders of different physiques. It is a result of a compromise between 'quick' steering and stability. It isn't a problem unless you like riding with your hands off the handlebars at these low speeds and is only transitory. Incidentally the floating top box plate is designed to reduce the effect when the top box gets buffeted at higher speeds.

[oldtimer03]

Even when experienced mechanics fit new steering head bearings, they can mistakenly think that they’ve been fully seated, but after a brief period of riding, braking etc, they can need retightening. That happened to mine, and a retightening sorted out the wobble just fine. Rev Ken is absolutely right though, so a minor residual wobble is nothing to be worried about. Keep your hands on the bars and it’ll disappear!

[MexiCan]

Thank you all for the reassuring comments. Unfortunately, the issue has taken away the sheer daily joy of riding a (formerly) well planted and stable bike. I guess I will have to get used to it. Just to be clear, the swaying is felt through the chassis, not the handlebars.

[Art]

In that case I'd suspect the rear wheel balance, tyre pressure or alignment but you say the dealer has already checked those.

Place the motorcycle on the centre stand and using and use a lever between the rear tyre and ground to check for any play in the rear end (wheel bearings, swinging arm and shock absorber)

[MexiCan]

Will do, thanks. A friend suggested increasing the dampening of the front fork. He reasons that it will diminish the tendency of the rear wheel to caster. I guess that's a simple thing to try too.