Be careful until you fix it. Jumping down a gear when your dragging a knee wouldn't be fun

 

yeah, that's why I'll run 3rd to 6k max. It's not too fun just going straight so I'd hate for it to happen in a corner, they'd be cleaning me up out of the trees haha. I'm just taking it easy with 3rd and skipping it when I want to run hard now to avoid the issue. 1st, 2nd, and 4th are good thru the entire rpm range, haven't gotten to where I can stretch 5th or 6th out much. There's a guy I work with that's continuesly trying to get me to sell him my bike, if I can get him up to 3k I may just do that and completely get rid of the problem haha

 

Check shift drum cam, detent arm and spring.

 

So I was riding home today and gunned it a little in third going uphill when I felt the shift lever push back down against my foot and shifted back down to second.

Don't know if that would help with diagnosing the issue but in my mind it seems that it would point more toward the shift forks and not the actual gears (which is what I'm hoping for)

Shift forks are something I should be able to get done in a day so I'm about half tempted to jump into it in the next 2-3 weeks but I'm afraid I'll do that and it ends up being the transmission or something more critical and time consuming

 

2nd and 3rd gear are selected by different forks. Therefore if the 3/4 selector fork was bent or worn, and the bike were to jump out of gear it would just go into a fake neutral. The fact that 2nd gear is getting selected means that something is also moving the selector fork for 2nd gear. Maybe the shift drum.

I could be wrong, after all it is amazing what some bikes decide to do to themselves.

 

The cause of a specific gear jumping is worn gear "dogs", the square tabs that stick out the side of the gear. When you shift, the gears move along the shaft and engage, disengage the gear next to it. When the transmission is beat on the dogs get rounded and don't stay engaged. It can be fixed but you'll probably need to install new parts.
I'm not a tranny expert but I remember this problem someone else had long ago.

 

Does anyone know if the gears, shift drum, and shift forks from a '87-'89 cbr1000f will work in a '96?

Been looking everywhere and found a few good deals on ebay but they're from an '88 and an '89 so I figured I'd ask instead of just assuming and spending money

 

How do you change the shift forks without splitting the case?

 

That would require magic.

Are you a Wizard?

 

Nope cannot say I am, only magic I've perform is being married to a hot Latina wife and getting her pregnant twice lol. FYI I'm a corn feed white boy so yea.

But the not splitting the case thing I've read mechanics doing it, that's why I ask. But o'well life's a B then you get hit by a minivan lol.