Egg shaped wheels

[exBanditOwner]

in 4th gear doing 40mph there is a weird sensation like the bike has Egg shaped wheels.
it sort of surges but slowly. like waves on the beach.

anybody else have this?

[flatfour]

Something very similar happened to my BMW K1200 RS after new tyres were fitted. Sorry to say that the cause was never found (wheel and tyre run - outs measured, wheels balanced three times by three different dealers, including a BMW Main Dealer). It was very noticeable at 40 - 50 mph (at least to me) but went away at lower or higher speeds.

As I was ready to change anyway, I sold it for the GTR. Apparently, the new owner didn't ever complain of the problem!

Perhaps after some 25,000 miles and five years of use, I was just too sensitive to the feel of the bike? (At the time that the problem developed, I went from one type of Metzeler, unfortunately can't remember which but probably Z6, to I think Z8).

[1ka]

Might be  RPM related, so:

Does it go away if you change gear?

Are you using ECO mode?

[shaggs147]

Yeah my bike tends to surge a little in eco mode around town. I tend to only use eco mode on the motorway now.

[pross]

Does this only happen at Easter 

[Ant]

Thats revving a little low in 4th gear at 40mph, is it not ? I never hit 4th until at least 50.  Its a bike that likes to be run above 3000rpm.

Might be a good idea to stick some premium fuel in a couple of times and steer clear of supermarket rubbish.

[exBanditOwner]

its not in eco mode. only going slow in 4th it's noticeable a bit in 5th at 40-50. i think it's something to do with the fuel injection and trying to keep a constant mixture. it might be slack in the secondary butterflies and it over compensating or something.
or even wind blowing hard against the inlets causing a ramair situation and then it trying to compensate.

it's not a massive issue.

it just a tiny bit annoying.

[exBanditOwner]

yeah it is a bit on the low side, but it's happy enough dawldling about through villages in the high gears.