Wobble at speed major 110 km/h on mk1

[biffa82]

Good morning group

HISTORY OF MY BIKE,
2007 MODEL MK1 ,4 MTH'S OLD WITH 41.500 KM.
TYRE'S  ARE GOOD & CORRECT TYRE PRESSURE (2.5 bar front and 2.7 bar rear).

I have a problem that is driving me lethally mad.
After changing the steering bearing (conical bearing fitted) and the tyres (fitted Metzeler M5) I notice a wobble from 110 km/h upwards.
I should point out that the steering doesn't wobble, the oscillation is of the whole bike horizontally, like when you get in the back of a car and feel the turbulence effect.
Now could it be that the M5 doesn't mate well with the CBF 1000 because the profile is too pear shaped ?
As part of my previous work on the bike, I replaced the forks (new).
Removing the panniers seems to improve the situation slightly (but the effect remains).
Any advice?
Many thanks

[Philby21]

Do you have a top box?  If so, is it genuine Honda?

The genuine Honda top box has a "floating" mounting plate that allows the top box to move.  It is a known issue that other makes of mounts can cause a wobble or instability at higher speeds.

Something to look at, if you have a box then maybe remove it and go for a test ride.

Otherwise I'd suggest checking that all your steering bolts are torqued correctly.

[Art]

If the wobble only came about after replacing the steering head bearing and the tyres then there is no point in looking any further than that.

Were the tyres and head bearing fitted by the same person? If that is the case take it back to them, the theory here is that the last person to repair it broke it.

If I was a gambling man I'd wager the tyres being most likely to be the cause. Maybe they were not balanced (unlikely) or, they were not balanced correctly or, a balancing weight has jumped ship or, the beads were not seated correctly.

Its also possible the steering bearing hasn't seated correctly, was it checked for seating after 500 miles of fitting?