6th gear slip

[CapeT400]

Hi all

I've had my CB400 Super Four Project Big 1 for about 2 years, ride her every day to work, and it's been a wonderful relationship so far :)
She's reliable, fun, and good looking... except suddenly this week, she started jerking in top gear. It's only when under load (i.e. not while decellerating or cruising at about 80km/h). If I open the throttle in top gear, she jerks, or slips, every 2 - 3 seconds. The revs jumps up about 200 rpm during the very brief slip...
No problem in any other gear.
I'm guessing it's something worn in the gearbox, but am holding out that there just *might* be something easier to check for before taking her apart

Thanks!
P.s. I've been struggling to find a workshop manual. not sure how old she is, but I guess late 90s or early 00s? Engine VIN: NC23E -1396.... Frame: NC31 -1026...

[amorti]

Hi all

I've had my CB400 Super Four Project Big 1 for about 2 years, ride her every day to work, and it's been a wonderful relationship so far :)
She's reliable, fun, and good looking... except suddenly this week, she started jerking in top gear. It's only when under load (i.e. not while decellerating or cruising at about 80km/h). If I open the throttle in top gear, she jerks, or slips, every 2 - 3 seconds. The revs jumps up about 200 rpm during the very brief slip...
No problem in any other gear.
I'm guessing it's something worn in the gearbox, but am holding out that there just *might* be something easier to check for before taking her apart

Thanks!
P.s. I've been struggling to find a workshop manual. not sure how old she is, but I guess late 90s or early 00s? Engine VIN: NC23E -1396.... Frame: NC31 -1026...

Check the clutch cable adjustment first, then if that's okay it's probably clutch plates and/or springs. Was easy to get for the CB-1 as it was the same as F1 CBR600, don't know for sure about your super-four.