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She's slippery above 7k RPM at full throttle


CB750 New member
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Every gear, whether I start at 1500rpm or 6k rpm, it slips around 7k. It will also slip into a neutralish state, like i'm driving a standard tranny car and didn't quite get it in gear....but there isn't a neutral between 3 and 4th gear. :confused:

I've changed her oil a couple times, replacing the filter each time. The first oil change that I completed at 22k miles, (I bought the bike at 20k) had small metal shavings in it. I haven't seen them in any other change, and I've done a chemical based engine cleaner after the last oil change. I figured maybe there was 20k miles worth of sludge and maybe it was causing the clutch to slip.

Before I put her out of commission, I'd love some advice, anybody ever experienced this?
At 22k miles I would bet the clutch is worn and the springs are weak. Weak springs are kind of common after a lot of miles. When you say neutralish state between gears, do you hear a gear clashing noise? Couple things cause false neutrals or jumping out of gears. The "dogs" on the gears are getting rounded, one or more shift forks bent or really worn, and I have seen the shift drum pins on the end of the shift drum get loose. My 836 motor would jump out of 3rd under hard accell.....it had worn "dogs" on the gear. In case you don't know what the dogs are they are the pins on the gear that engage in the slots of the adjacent gear. The more it pops out of gear the more it rounds the corners off the dogs, when they are rounded off they don't stay engaged in the other gear. You can put new gears in or have a good set of gears "undercut" which puts a bevel on the dogs so they can't slip off the other gear. I put an undercut gear set in my motor and never jumps out. If a shift fork is bent or worn it wont push the gear all the way into the adjacent gear thus letting it pop back out. Only fix for gears or the forks is to split the case. Hope some of this makes sense.....If not let me know and I will try explaining more in depth.
So sorry for the huge delay in my response! I figured that is what it was. I'm going to end up tearing the motor apart anyways to do the 836 kit on it and my girlfriends bike (she has a twin to mine). Thanks dirtdigger!
dirtdigger, nice explaination! :thumbsup:

SingleSpeed4815, your girlfriend rides a CB750!?! :) Let see those bikes!
So, I believe this is happening to the bike I just bought under hard acceleration. I was wondering how difficult the diagnosis is and the repair? I have rebuilt a c6 ford transmission that is good for 800hp but this is my first time working on a bike. Any help/pointers would be appreciated.