Topic: Second gear dropping out - is it my fault??

[pinkrimracing]

I today finished (well, for now) my cb750 and took it for the first ride around town. The engine was rebuild by previous owner and though im not certain what has been done, the top end was completely rebuilt and ported by renowned firm here in Sweden, so my guess is he paid some interest to the rest of it.

On the ride, first gear made a stutter almost as if the clutch would slip, and at 4k revs, it spits out second gear. My guess is forks and/or dogs, but.. It might be me as well.

I won’t use neutral light and as it was leaking from the neutral switch, I made a plug on the lathe to solve the leak. Could removing the neutral switch be the source of the problem? Sounds stupid, but I’m grasping straws not to tear the engine down. I just want to ride it..






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[scottly]

Could removing the neutral switch be the source of the problem?

YES!!! The small diameter at the end where the ball is fits into a groove in the shift drum, and locates the drum laterally in the case.

[pinkrimracing]

Could removing the neutral switch be the source of the problem?

YES!!! The small diameter at the end where the ball is fits into a groove in the shift drum, and locates the drum laterally in the case.

Ok. Just remove the plug and re-install the switch, or is it to late and I have spun something?
Gears 3-5 worked fine. If this is the case, I might just be a lucky man.


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[scottly]

Yes, just reinstall the switch; you may have to shift the drum to one side or the other to get the groove lined up.The switch body needs to be fully seated. Insert the o-ring in the case first. I don't think it would damaged anything?

[69cb750]

On the ride, first gear made a stutter almost as if the clutch would slip, and at 4k revs, it spits out second gear. My guess is forks and/or dogs, but.. It might be me as well.

There is an indent in shifter drum for neutral switch however this is unrelated to 2nd gear.
When shifting gears you can feel it lock in position from spring and lever of shifter drum.
If other gears lock in and 2nd jump out your dogs and/or fork are worn.

[pinkrimracing]

Just got back in. It’s 3.36 am and MOT in 7 hours and hopefully this is the solution. It wasn’t the case of just pushing the switch back in. I had to remove the left side engine case and push the shift drum back in about 3-4mm. That made it possible to push the switch in and locked the drum from moving out again. Will report back tomorrow.

Per


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[scottly]

If the switch is fully seated you should be good to go.

[pinkrimracing]

Just arrived for inspection. First since 1990 and if all is ok, I can use it. Gears stayed in place on journey here so I’m a happy boy.



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[ekpent]

 That's good new and nice looking bike. You will have to tell us more about it. You have a fellow countryman also named Per on the forum who is very knowledgeable on these 750's also.

[PeWe]

Yes, Per was a popular name half a century ago
This is a good reminder to others what purpose the neutral switch has.
Remove kick axle another not do thing when minimilize the bike.

This forum a good place to learn more about the old CB's.