Topic: 1980 CB750F DOHC slipping out of 4th gear into 3rd

[jtai]

Hey all,

New member here with a transmission question. Occasionally under heavy acceleration my 1980 CB750F "Super Sport" will pop out of 4th gear into 3rd - NOT a false neutral since the rear wheel is still driven albeit at a higher RPM when this happens. Revs don't just shoot to the moon. I've done some preliminary research about this and people mention 3-4 different general causes in order of frequency left to right: worn dogs, worn shift forks, worn shift drum, or worn roller detent. Wondering if anybody has experience with this exact or very similar issue and what was done to remedy it.

My second question: is there any way for me to adequately inspect and/or pull the transmission without having to remove the engine/split cases? I just want to know what I'm getting into before pulling this thing apart. The problem is not yet serious enough for me to just rip into it and frankly it's an old bike anyways...no need for me to WOT in 4th gear on a 42 year old bike. I'd be happy just enjoying it under 7k rpm around town, just want to make sure nothing's gonna grenade the motor any time soon.

[Alan F.]

Get a genuine Honda Factory Service Manual and investigate each one of these suggestions. Some can be checked without splitting the cases, others are more invasive. Keep it simple.

[jtai]

I've got the Clymer but no particular mention of this issue. I'll have to look again and double check.

[Alan F.]

Clymer manuals are not highly regarded for their accuracy. There are errors that can put you in a really bad position. We don't recommend them for anything other than door stops, beer coasters or to place under your kickstand to get a better angle to photograph your bike.