Acceleration Flat spot

There appears to be a "flat spot" when accelerating through 4th gear, there's a little blip as if I've dipped the clutch and let it out again.

It doesnt appear to happen in any other gear but 4th.

Anyone have any ideas? The bike was just MOT'd today.

[Bibio]

might help a bit more if you could give us what speed and revs it happens.

d'oh, thought i had...

40mph or 4k revs in 4th gear....

the bike has never done this before, first time i've ever noticed it tonight.

[Bibio]

so its just started and it doing all the time?

yup, started tonight on a run from Johnstonebridge to Home, changing up through the gears into 4th get to 4k revs and it kind of slowed like the clutch had been pulled in, and then it powered on through and was fine in all other gears...

[Bibio]

hhhmmmm. have you tried holding at 4k in other gears?

Mine feel like this sometimes, as if i have the clutch half pulled in when i try to open up and so doesnt pull away like it should, checked clutch and its all adjusted fine....

Hmmmm

yup tried that Bib, no issues at all.

Webber, thats exactly what it feels like!

Yer not sure what it is, only noticed it recently, maybe clutch plates? But i know little of that kind of bike tech, so no idea if its that or not.

[Bibio]

hhhmmm. so fine in 4th till 4k then a sudden dip then ok again after 4k and only in 4th.

strange one that as flat spots tend to affect all gears.

so i haven't a clue. maybe our resident spanner monkey Y_C might have a better idea.

i was going to say fuelling or a duff plug/coil/lead. but that would effect all gears.