Topic: Gearbox problems CB750 F1 1976

[olasek18_18@o2.pl]

Hello Guys,
18 000 miles ago I was rebuild engine, checked Gearbox, all sprockets and selectors...
In the end of this sezon after 10 000 miles riding I observe my gearbox started working strangely.
Namely, almost every time I change gear, I feel a slight resistance, sometimes I have the impression that it jumps in 2 stages of "click-click"
Gears do not fall out, it is very rare to switch between gears 2-3 ,3-4 ,4-5
I changed oil from 10w50 to 10w40
can oil affect this?
I Have CB550 too and this beauty changes gears very smoothly always.
Do You have the same? Any Suggestions?

Kind Regards

[olasek18_18@o2.pl]

Maybe it's normal in CB 750?

[Bankerdanny]

After the rebuild and 10k miles a clutch adjustment is probably a good idea. If the clutch isn't completely releasing when you pull the lever in then you will get extra resistance when changing gears.

I would not think that the weight of the oil will make a difference.

My '76 750F shifts easily, but you can definintely feel it changing gears as you move the lever

[halllzy]

I’m not a huge fan of change.

If 10w50 worked, I’d say start with an oil change back to it and see if that makes a difference.  It’s a pretty low cost/time troubleshooting step.

+1 for clutch adjustment



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[70CB750]

How are the bolts on the cover?  Did you use paper gasket?

[olasek18_18@o2.pl]

After the rebuild and 10k miles a clutch adjustment is probably a good idea. If the clutch isn't completely releasing when you pull the lever in then you will get extra resistance when changing gears.

I would not think that the weight of the oil will make a difference.

My '76 750F shifts easily, but you can definintely feel it changing gears as you move the lever

Ok, so should I regulate bolt/nut inside clutch cover?
Because pulling up the clutch cable only changes the handle position, yes?

[olasek18_18@o2.pl]

How are the bolts on the cover?  Did you use paper gasket?

I did use oryginal gasket, You mean regulate bolt inside cover?

[Bankerdanny]

After the rebuild and 10k miles a clutch adjustment is probably a good idea. If the clutch isn't completely releasing when you pull the lever in then you will get extra resistance when changing gears.

I would not think that the weight of the oil will make a difference.

My '76 750F shifts easily, but you can definintely feel it changing gears as you move the lever

Ok, so should I regulate bolt/nut inside clutch cover?
Because pulling up the clutch cable only changes the handle position, yes?

Adjusting at the handle does affect more than the lever. You are basically taking out or adding slack to the cable, so too little adjustment at the lever will mean the cable doesn't pull the lever at the engine side as far. But a proper adjustment should start at the engine side, then finish at the lever. If you don't ahve it you can download the factory manual here at the forum with the correct  instructions.

[70CB750]

How are the bolts on the cover?  Did you use paper gasket?

I did use oryginal gasket, You mean regulate bolt inside cover?

My 78F motor was sensitive to how tight was the bolt right next to the shifter.   Later on it went away with paper gasket - turns out just Hondabonding the cover influences shifting.

If there is a change in shifting, I would pull the cover and check on the linkage, you might lost or broke a spring for instance.

[maxheadflow]

How are the bolts on the cover?  Did you use paper gasket?

I did use oryginal gasket, You mean regulate bolt inside cover?

My 78F motor was sensitive to how tight was the bolt right next to the shifter.   Later on it went away with paper gasket - turns out just Hondabonding the cover influences shifting.

If there is a change in shifting, I would pull the cover and check on the linkage, you might lost or broke a spring for instance.

I'll bet it does. You kill the endplay in the shift shaft and cause it to stick.

To OP, Check you shift detent rollers.

[brianc]

I have an F2 750 which I had changing gear issues. Not quite the same as you describe, but sluggish, crunchy and generally un- Honda. Oils? Chain? Adjustment? Free play? nope all around. The clutch centre splines that the steel plates run on was worn, preventing full release. A new one would be nice, but I carefully cleaned off the dents and bingo nice clean changes!

[Tracksnblades1]

I have an F2 750 which I had changing gear issues. Not quite the same as you describe, but sluggish, crunchy and generally un- Honda. Oils? Chain? Adjustment? Free play? nope all around. The clutch centre splines that the steel plates run on was worn, preventing full release. A new one would be nice, but I carefully cleaned off the dents and bingo nice clean changes!

😇

You've must have a few dirt bikes too.