So I just picked up a 94 900cc cbr. Slips second gear over 3k rpm. Ive heard under the oil pan, I can access the forks to see if they need replaced (most likely). Does anyone have a link to a guide that I can follow? I am pretty mechanical, but not the best by any means. It's dark outside and I can't mess with it tonight. Any help would be appreciated.

 

When you say slip, do you mean it clunks and goes out of gear and the rpms go instantly high? Or do you mean slip as in there is no noise, but
the rpms just increase and the bike doesn't accelerate like it should?

If your not hearing any noise, it could just be a weak clutch.

How does it shift otherwise? A bent fork will usually be hard to shift into gear. Besides, I don't think you will be able to visually inspect the shift fork to see if its bent.

having said that. Second gear is the most common gear to chip. Mainly because so many people clutch up wheelie's in second. If its a chipped tooth, it will clunk, pop out of gear, rpms instantly high. it could go into neutral, but it could also pop back into gear. If the problem is only in second gear, I'd suspect the gear. Which is not good since the entire engine needs to separated. You have to split the engine case to get to it. So make sure what the issue is first.

As for actually being able to see the forks from the oil pan, Im not sure. Hopefully someone here will be able to add som assistance. But it may not be a bad idea to remove the pan anyway. You may find a piece of the gear in the pan. If you do, you will have found your issue.

 

like said 2nd gear gets the most abused. Check out YZF600R Forums • View topic - DIY Comprehensive 2nd Gear Fix W/ lots of pictures as this is a popular problem for yzf600's. This will give you insight on the general problem.

 

It will change to 2nd. Than after about 3-4k rpm, it will drop into neutral and because I have throttle going, it will rev pretty high. I have to change to 2nd than immediately to 3rd with clutch in.

 

I also run into that same problem you are mentioning. Sometimes I dont think I put enough upwards force when shifting, so it only goes halfway. There is a spring in charge of relocating the shifter after a shift, and the mechanism sometimes doesnt catch. Check out this video of how the shifting is done to give you and idea.

‪YZF600R Shift Shaft and Factory Pro Shift Kit (Part 4) - Krab Boil‬‏ - YouTube

 

I shift up pretty hard. It does go into 2nd. After a specific RPM it will drop into neutral.