Topic: CB500 Clutch Stiff

[rtbmrgl]

Good afternoon.
My 73 CB500 clutch lever can’t be pulled all the way to the grip. It has about 1/4” of play between the lever and pedestal. If feels like the spring is binding, like to thick of a spring. It has Barnett springs and new oem Honda friction discs. Also the clutch if stiff. It has the original clutch cable.
A little history, I got the bike ten years ago from the original owner with 1243mi.

[rtbmrgl]

An update, i fiddled with the clutch adjustment at the side cover, seems ok now. not sure why it did that all of a sudden. all the mechanism and rod is lubbed.

[bryanj]

Ditch the barnett springs and fit a new, correctly routed cable DO NOT LUBE THE CABLE

[rtbmrgl]

Thanks, got OEM on order.

[bryanj]

Springs or cable or both? OE cables are rare now

[HondaMan]

+1
The OEM springs are plenty strong and the Barnett springs can damage the screw thread of the 500's clutch lifter pretty quickly(!). They are near impossible to replace nowadays, too. The long clutch rod can also suffer from high spring tensions, like by breaking in half.

Make sure it is clean inside the screw lifter, and well-lubed. I used to drill/tap in a tall-necked SAE grease fitting there to make it easier to grease: the JIS type grease fitting tends to push the SAE zerk heads of grease guns right off the fitting with the pressure.

[PeWe]

CB500 (for the smaller CB's too) Barnett springs are stiffer than the CB750 version. Middle number is -66-. CB750 -56- which is the spring rate in lb.

Dynoman sell them as dragrace version for CB750.

[HondaMan]

CB500 (for the smaller CB's too) Barnett springs are stiffer than the CB750 version. Middle number is -66-. CB750 -56- which is the spring rate in lb.

Dynoman sell them as dragrace version for CB750.

Yep. That's the difference between soaking-wet clutches and barely-oiled ones!

[PeWe]

CB500 (for the smaller CB's too) Barnett springs are stiffer than the CB750 version. Middle number is -66-. CB750 -56- which is the spring rate in lb.

Dynoman sell them as dragrace version for CB750.

Yep. That's the difference between soaking-wet clutches and barely-oiled ones!

Ok, so that is why.
The stiffer CB500 and smaller CB, black springs.
CB750 golden.

Are Barnett CB750 springs possible for CB5x0?
If an upgrade.

The rest of the clutch must cope with the springs too.
CB750 has aftermarket  billet lifter plates while the clutch plate with its tiny fingers with threaded holes for the M6 bolts holding all together look weak.

CB5x0 has more of that I suppose.

My K6 must have the stiffer ones. I tried to use the weaker (golden) again at the beginning of last year.
Abrupt slip like wheel spin when giving some throttle on 3rd gear. Fresh EBC fibers, F2 clutch and glass beaded metal plates. Bigger bore and much more torque.

Not that hard after I lubed the clutch cable and made sure it was smoothly routed without sharp corner. .



I replaced the clutch lever from stock style to dog leg type to make life easier for my clutch fingers.
Photo with stock style lever under to show where a finger or 2 can get a  closer and better grip

[HondaMan]

Well, the Barnett 'upgrade' clutch for the 500 (this was before the 550 appeared) consisted of plates with square-cut cork plates, but no new springs. This was/is because the slant-cut cork plates always slip longer under power at starts (by design), which was another part of the overall smoothness that was promoted as the new CB500 bike. If you tried a dragrace start with the stock CB500 clutch it sounded like the clutch wasn't grabbing at all until halfway thru 1st gear toward redline. Shifting into 2nd hard and fast would make it do that again, but somewhat less. So, of course, every racer decided that clutch had to go, and Barnett was the first to step up with plates like the 750 had, but thinner (the 500 plates are about 0.010" thinner than the 750 plates) and then you could stall the bike with a dragrace start unless you had lots of finesse - because the engine didn't do burnouts, at least in stock trim.

But it is/was very smooth.