Topic: 74 CB750 wanting to switch to hydraulic clutch

[archimeech]

Hey all,
I haven't seen anyone bring this up lately, but don't flame me if it's out there.  i've got a 75 bike with a K4 motor on it.  I've probably replaced the clutch cable about 5 times.  Not sure if it's my working the clutch or that I have it outside under cover, but in the hot humid southeast of the US and the cables just seem to go.  I was looking at the BMW/Husqvarna Magura Hymec clutch assemblies.  It's an exterior master piston that looks like it would fit the cable adjustment location fairly well.  Has anyone tried this out or am I just going down a rabbit hole that I won't come out of?

[Steve_K]

Are you using a Honda cable and is it routed correctly?  My cable on my 73 750 and the one on my 76 550 are, I believe, original and still work very well.  A Honda cable would be cheaper and easier than converting to  a hydraulic clutch.
Steve

[grcamna2]

OEM Honda cable and keep it lubed with heavy spray grease,the kind that sprays into a cable from a special cable lube tool.I also use synthetic chain lube,it'll stay put if you use the right stuff.Do you still have your cable boot that covers the upper lever area ? That way water won't get in.

Edit:Routing,definitely 

[Bodi]

I bought a used (not sure what bike it was from) slave cylinder and hydraulic lever for my 400F several years ago. I have a spare motor and I could machine that to mount the slave cylinder, but when I got the price for the machine shop work I decided to wait until I could afford it. The hydraulic bits are still in a box somewhere. Carefully routing the cable according to the service manual got the lever effort acceptable (but still stiff - stronger clutch springs installed to handle the 466 horsepower).

[ekpent]

 A buddy of mine somehow did it to a cb350 I sold him. He's making a pretty cool custom cafe thing out of it.

[seanbarney41]

Hey all,
I haven't seen anyone bring this up lately, but don't flame me if it's out there.  i've got a 75 bike with a K4 motor on it.  I've probably replaced the clutch cable about 5 times.  Not sure if it's my working the clutch or that I have it outside under cover, but in the hot humid southeast of the US and the cables just seem to go.  I was looking at the BMW/Husqvarna Magura Hymec clutch assemblies.  It's an exterior master piston that looks like it would fit the cable adjustment location fairly well.  Has anyone tried this out or am I just going down a rabbit hole that I won't come out of?

I have seen those slick little Magura set-ups on dirt bikes and thought it would be pretty easy to make it work on a cb...but a properly functioning 750 clutch works pretty smooth stock.

I have broke clutch cables before, but it was old, crusty, un-sorted bikes.  Does yours always brake in the same place?  If so it is probably improperly rubbing on something.  Investigate before you spend tons of money.

[754]

There was a guy on here did a few, the Big Brake guy.. Fishhead I think, might be able to search for it.
 Where is it breaking ? Often guys never grease the barrel end of the cable in the hand lever.... then it starts breaking strands.

[low-side]

I agree with the others here, if it's breaking that frequently, something is wrong.  OE should last decades and cheap ones should last year's with proper maintenance, even in humid conditions.  The simplest setup I saw was a plate boltedin where the stock chrome cover goes, and then the slave cylinder was bolted to that.  They turned their own pin on a lathe.  I think the donor bike was a VF750 or something along those lines.  I would think that it would cost several hundred minimum to do the conversion, so if the cable issue is the only reason you want to do it I would figure out why your cables keep breaking.  If you want an easier clutch pull and a unique feature on your bike, go for it.  Either way, good luck with it.

[archimeech]

I use Motion Pro cables and have them routed correctly.  It's always the same spot.  Right where the top lug is attached to the cable and fits into the lever. 

To answer another question, no I don't have the rubber boot at the top that covers it, but I do keep it lubed.  I may have to buy a new clutch lever.  maybe it's rubbing or pulling at an odd angle and distresses the cable right at the pull point.

[754]

There was a guy on here did a few, the Big Brake guy.. Fishhead I think, might be able to search for it.
 Where is it breaking ? Often guys never grease the barrel end of the cable in the hand lever.... then it starts breaking strands.

Second paragraph, read it , its exactly your problem . HONDA I think had a plastic sleeve over most of the barrel to make it pivot easier. Grease will last longer than oil here.
 HARLEY came up with a better system 20 years ago, a metal eye end on the cable , that pivots ona pin. After our bikes,  leavers improved both on their own pivot and that off the cable.

[bryanj]

Is it breaking at the top lug or pulling out of it

[grcamna2]

I use Motion Pro cables and have them routed correctly.  It's always the same spot.  Right where the top lug is attached to the cable and fits into the lever. 

To answer another question, no I don't have the rubber boot at the top that covers it, but I do keep it lubed.  I may have to buy a new clutch lever.  maybe it's rubbing or pulling at an odd angle and distresses the cable right at the pull point.

Motion Pro cables aren't what they used to be.. I would rather use the Honda part# and search online for an  OEM Honda cable,even NOS stock cable can be found this way.I agree with applying grease at where the ball-end inserts into the hand lever.

[archimeech]

It snaps right at the lug where the cable comes out of it.  and the Motion Pro ones still have the plastic sleeve.  I may have to go NOS though, it it'll work.

I use Motion Pro cables and have them routed correctly.  It's always the same spot.  Right where the top lug is attached to the cable and fits into the lever. 

To answer another question, no I don't have the rubber boot at the top that covers it, but I do keep it lubed.  I may have to buy a new clutch lever.  maybe it's rubbing or pulling at an odd angle and distresses the cable right at the pull point.

Motion Pro cables aren't what they used to be.. I would rather use the Honda part# and search online for an  OEM Honda cable,even NOS stock cable can be found this way.I agree with applying grease at where the ball-end inserts into the hand lever.

[seanbarney41]

It snaps right at the lug where the cable comes out of it.  and the Motion Pro ones still have the plastic sleeve.  I may have to go NOS though, it it'll work.

I use Motion Pro cables and have them routed correctly.  It's always the same spot.  Right where the top lug is attached to the cable and fits into the lever. 

To answer another question, no I don't have the rubber boot at the top that covers it, but I do keep it lubed.  I may have to buy a new clutch lever.  maybe it's rubbing or pulling at an odd angle and distresses the cable right at the pull point.

Motion Pro cables aren't what they used to be.. I would rather use the Honda part# and search online for an  OEM Honda cable,even NOS stock cable can be found this way.I agree with applying grease at where the ball-end inserts into the hand lever.

I have used motion pro cables many times over the years.  They are not as good as oem but work and last fine.  You need to find what is causing them to break.  Could be as simple as a sharp burr raised on your clutch lever, perch, or barrel adjuster.  We might be able to help find it with good close up pics of each.

[754]

Lack of lube or a lever that does not allow it to run pretty straight into the adjuster.
 How often did you lube the top part ?