Handlebar Wobble

[velocipede6295]

It was quite a nice day today so I went out for couple of hours on the Forza ( it's great being retired! ) and had an enjoyable trip, but with one problem. When I slackened my grip on the handlebar grips I got a very noticeable wobble/shake on the bars, as the bike decelerated. The shake was very pronounced the longer it went on, I only did it momentarily, say 1-2 secs, before I again gripped the bars with a light grip, and it immediately stopped.
The scooter has just been MOT'd at the supplying dealer, so I would have thought any problems with the forks, or steering head bearings would have been found, but it passed with no advisories.
I checked the tyre pressures, which were OK, the City Grip tyres have plenty of tread, and do not look to have worn unevenly, and the front axle bolt is tight. I noticed if I leaned a bit further forwards, putting more of my weight on the front, the wobble did not disappear, but was less pronounced.
I have a large ( 42L) top box which only had some very light contents - a cap, screen cloth, neck tube etc.
My next step is to remove the top box tomorrow, and try riding without the top box, and see how that goes. Has anyone got any other suggestions?
Thanks - Malcolm

[mottza]

Old tyre maybe

[Greyerbeard]

Don't necessarily trust the MoT test - can you check the head and wheel bearings yourself while you prop the bike up; or someone else holds the tail down?

[roadster]

This is a tricky one! I've had bikes and scooters that showed signs of this when practically new, usually just in one lowish speed range. Its true that the MOT has very little relevance and its worth checking basics yourself. What is behind the rider is as important as what is in front and sometimes its aerodynamics rather than weight that makes a difference so taking off the top box may change things. Does it happen on all road surfaces and does changing tyre pressures (within reason) make any difference? Are there any extras such as wider mirrors or different bar end weights affecting the handlebars?

Once you have checked the basics and are satisfied that the tyres are safe and don't have peculiar wear patterns it would in my opinion be something that could be ignored unless it becomes a problem when lightly holding the bars too. In the past I have noticed that some tyre brands ( Continental being worst ) square off badly on the back and cause instability but this is more of a weaving than a wobble.

[Andym]

The only relevance I would place on the MOT was if they adjusted anything and that's when it started. It should just be a clipboard exercise in seeing if your bike is from the 1960's by tapping the plastic with their anti-rust hammer and then paying the bribe to make them forget you didn't contribute anything by VAT on new bikes this year. They achieve nothing of real substance on modern machinery.

Check tyre pressures then the head bearings.

Andy

[velocipede6295]

I've adjusted tyre pressures to exact spec as per book - they were actually a couple of PSI down, both tyres are in good order with plenty tread left and look to be quite evenly worn, also checked wheel /fork/head stock play - no play detected, removed top box - no difference, tried with screen up /down, axle bolt tight. Mirrors and bar end weights are standard. The shake/wobble is worse on rougher uneven roads, but stops as soon as I re grip the bars even slightly, and normal riding does not show up the problem, when I am holding the bars normally.
I've not ridden the Forza much this year but I do remember something similar similar in previous years, so it's not just suddenly come on. I've checked the basics, and I am satisfied with the tyre condition, with no unusual wear pattern, and as there is no problem when I hold the bars lightly, I think I will go with roadster's advice to ignore it, unless it starts to happen when holding the bars lightly.
Thanks for everyone's advice and input, much appreciated.

Malcolm

[Bellman]

Interesting, I have the same 2019 Honda Forza 300 model, I bought mine in October 2018 so I've had mine seven years. There's not a lot I can say about mine, it' also has Michelin Citygrip tyres with plenty of tread on them, and I regularly check tyre pressures and set them to Honda's recommended pressures.

I have the the larger Givi screen and bodywork mounted hand wind protectors which I fitted as soon as they came on he market in early 2019, and a Givi E55 top box which doesn't make a difference to riding whether it's empty or full.

Apart from a new Yuasa battery I fitted earlier this month, I've had no issues with my Forza whatsoever. In fact the new battery seemed to give the Forza a bit more pep. I've certainly never experienced any handlebar wobble, in fact I was quite surprised to read your post..

I'm not into the maintenance, tinkering, and spannering side of maxi ownership, I just grudgingly do what's necessary. So as a rank outsider guessing, could your handlebar wobble be due to losing one of those balance weights on your front wheel?

[Greyerbeard]

One final thought - are you sure it's 'wobble' and not 'white lining'? Any tyre can do this depending on road imperfections, patches of damp, changes in road surface etc...seemingly at random depending on the mood of the tyre, time of the month and so on!
Even my ADV350 was doing it the other day on one patch of streaky damp road, and that's normally rock solid.

[Waldorf]

Serious question: How does one hold the handlebars abnormally?

[roadster]

Serious question: How does one hold the handlebars abnormally?

I would interpret normal as holding them with a relaxed grip rather than grasping them in panic and locking arm sinews. Perhaps a few will remember the speed wobble at 90 mph on the Norton Commando that induced this behaviour instinctively ( but ill-advisedly) !