75 CB750 Clutch Problem

[jamcamcb750]

Hi all,

Relatively new to the group. I’ve got a 1975 Cb750 and it’s got a clutch problem that I’m looking to fix but wondering it if I can get some pointers on what the problem might be before I venture into fixing it.

The clutch pull is very light and all of the take-up happens right at the very end of the lever. I.e only about the first 10mm or lever pull is fully disengage/engage, the rest of the pull all the way back to the grip does nothing.

It’s annoying because In the action of changing gears quickly (normally) you always get a big rev of the engine because there’s a brief period when of throttle not fully shut off and clutch disengaged.

It’s not a cable adjustment issued as I’ve fiddled with both ends to no avail.

Likely to be springs? Worn plates?

Any help is appreciated

 

[AutoMac]

If the plates are worn you will get a lot of revs and not much go ( clutch slip ) this can be down to a worn friction plates or worn steels .
Or even incorrect oil being used. Once removed place the steels on a flat piece of glass to see if they are warped.

A recalcitrant clutch action can possibly be weak springs, your workshop manual should tell you the length of them . Remove them and place them on a flat surface and measure them if they have compressed don’t be tempted to get so called up graded heavier springs unless you are racing it. I suffer from bad arthritis in my clutch hand from years of pulling in heavy clutch levers. A strong clutch pull isn’t necessary and genuine springs are available from places like David Silver Honda Specialist in the UK , but they are a service item so you shouldn’t have a problem getting standard replacements, they can be also obtained on back order from a Honda motorcycle main dealer if you have a problem finding a supplier.


It could also be your clutch basket has worn internal grooves making the clutch action difficult. It is an easy fix , remove the clutch and re dress the tangs on the clutch basket with a small light file or emery paper until they have no more ridges. ( Best done off the bike)
Don’t be tempted to jam a screwdriver or bar through the clutch basket to hold it whilst you remove the centre nut as sometimes they are on really tight and it will just snap a tang off the basket. When re fitting your manual will tell you the correct torque wrench setting.

Best practice is to go on line and get a clutch basket holding tool to fit the CB. They are not expensive and saves a load of grief trying to find a replacement clutch basket. I got mine from a company here in the UK called Wemoto. I hope this helps.
PS nice looking bike

 

[jamcamcb750]

If the plates are worn you will get a lot of revs and not much go ( clutch slip ) this can be down to a worn friction plates or worn steels .
Or even incorrect oil being used. Once removed place the steels on a flat piece of glass to see if they are warped.

A recalcitrant clutch action can possibly be weak springs, your workshop manual should tell you the length of them . Remove them and place them on a flat surface and measure them if they have compressed don’t be tempted to get so called up graded heavier springs unless you are racing it. I suffer from bad arthritis in my clutch hand from years of pulling in heavy clutch levers. A strong clutch pull isn’t necessary and genuine springs are available from places like David Silver Honda Specialist in the UK , but they are a service item so you shouldn’t have a problem getting standard replacements, they can be also obtained on back order from a Honda motorcycle main dealer if you have a problem finding a supplier.


It could also be your clutch basket has worn internal grooves making the clutch action difficult. It is an easy fix , remove the clutch and re dress the tangs on the clutch basket with a small light file or emery paper until they have no more ridges. ( Best done off the bike)
Don’t be tempted to jam a screwdriver or bar through the clutch basket to hold it whilst you remove the centre nut as sometimes they are on really tight and it will just snap a tang off the basket. When re fitting your manual will tell you the correct torque wrench setting.

Best practice is to go on line and get a clutch basket holding tool to fit the CB. They are not expensive and saves a load of grief trying to find a replacement clutch basket. I got mine from a company here in the UK called Wemoto. I hope this helps.
PS nice looking bike

Thanks for a comprehensive reply. Appreciate your help.

 

[cmg]

If the plates are worn you will get a lot of revs and not much go ( clutch slip ) this can be down to a worn friction plates or worn steels .
Or even incorrect oil being used. Once removed place the steels on a flat piece of glass to see if they are warped.

A recalcitrant clutch action can possibly be weak springs, your workshop manual should tell you the length of them . Remove them and place them on a flat surface and measure them if they have compressed don’t be tempted to get so called up graded heavier springs unless you are racing it. I suffer from bad arthritis in my clutch hand from years of pulling in heavy clutch levers. A strong clutch pull isn’t necessary and genuine springs are available from places like David Silver Honda Specialist in the UK , but they are a service item so you shouldn’t have a problem getting standard replacements, they can be also obtained on back order from a Honda motorcycle main dealer if you have a problem finding a supplier.


It could also be your clutch basket has worn internal grooves making the clutch action difficult. It is an easy fix , remove the clutch and re dress the tangs on the clutch basket with a small light file or emery paper until they have no more ridges. ( Best done off the bike)
Don’t be tempted to jam a screwdriver or bar through the clutch basket to hold it whilst you remove the centre nut as sometimes they are on really tight and it will just snap a tang off the basket. When re fitting your manual will tell you the correct torque wrench setting.

Best practice is to go on line and get a clutch basket holding tool to fit the CB. They are not expensive and saves a load of grief trying to find a replacement clutch basket. I got mine from a company here in the UK called Wemoto. I hope this helps.
PS nice looking bike

It could be as simple as the cable is too long and u can't adjust the extra length out. Just saying....