Working on hydraulic clutch mod

[wolds]

So I have been busy working on the conversion of my clutch system from mechanical to hydraulic and made great progress over the weekend. The mod as others have pointed out is pretty straight forward. I used the following components.

Clutch M/C: 1984 Honda Interceptor VF750 (14mm bore) (ebay)
Clutch Slave: 1986 Kawasaki GPX750R (34mm bore) (local MC junk yard)
Clutch push-rod: 8mm Shaft 300mm 12" Hardened Rod Rail Linear Motion 3D Printer XYZ for lm8uu (ebay)
backing plate: 1/4" aluminum

I started by making a plug out of delrin that would fit into the existing opening of the clutch mechanism so that the pilot of the 1-3/8" hole-saw would remain centered in the existing opening assuring alignment with the clutch rod. I used a vertical mill to make the hole and the two counter bores for the mounting screws but a drill press would also work. Next I trimmed the webs on the backside enough that the aluminum plate would lay flush. Once JB welded in place I drilled pilot holes through the aluminum and tapped to 6X1mm. For my install I used three stainless washers stacked under the mounting ears to get the slave to rest on the ears so that when screwed down the slave would remain true and not become distorted from being bent around the radius of the cover. The clutch push-rod ended up being 272mm long in my case. I dished the end that contacts the slave so that the rod would remain centered on the ball bearing that it rides on that is set in the piston the other end retains the ball bearing that was used in the original two-piece rod. I'm going to fabricate a felt pad that will seal the end of the piston and will contain the small dab of grease to provide lubrication between the rod and the ball bearing. Because I have the engine on my bench with the RH side cover off I was able to measure the linear travel of the stock setup against the hydraulic unit with a dial indicator. I measured .056" of travel for the stock setup and .090" for the new one. This setup should make finding neutral when the motor is at operating temperature much easier. When the bike is back on the road I'll report my results. I have included a few pictures for clarity.

 

[pago cruiser]

Great write up! Thanks for taking the time to do this.
Have a question - I've looked at this in a couple other posts on other sites, and most seem to do it this way - from the outside.
Did you think about doing it from the inside to keep it more stock looking? It may be that you can't get as much throw as you did.
Would appreciate your input.
TIA

 

[wolds]

TIA,
I thought about mounting the slave on the inside of the cover which I think can be done but since mine is going on a cafe bike that is a long way from stock I took the easy way out. Mounting the slave on the inside might also complicate bleeding the system but I'm guessing there are ways around that issue. I'll have the engine back in the frame over the weekend and will be routing the line to the grip via a hard line that will follow the lower frame tube up near the steering head. I'll use SS braided lines at each end to connect to the M/C and slave. When I have that worked out I'll post some more pictures and another "write-up".
Warren

 

[wolds]

So I have completed the install and can report that with the new hydraulic system in place I increased the linear travel of the pushrod from 0.056" to 0.100". Ended up running a 3/16" brake line along the backbone of the frame and used a 12" SS braided hose to the slave and a 18" SS braided hose to the M/C. Haven't ridden the bike yet (it will be a few more weeks) but clutch action feels good. The real test is how it feels with the engine at operating temperature.

 

[Paul Sutton]

Will be interesting to see if this hydraulic system automatically adjusts itself to cope with the engine expansion during the warming up phase i.e. Will finding neutral still be just as smooth at startup compared to say 30 minutes later?

Keep up the good work!!!

 

[johnnyc14]

Cool, nice job. looks like you and I used the same slave cylinder. Mine came from a 95 ZX900 but it looks the same as yours. I'm running the ZX9 master cylinder and it is 14mm bore also. I'm getting about .100" of pressure plate travel also but I haven't had the bike running since the hydraulics were installed. I used a Russell braided steel line. I milled a flat surface on the outside of the cover to mount the slave flat.

I'll let you know how mine works when I get the bike finished.

http://www.xs650.com/threads/new-member-starting-a-project-650.37965/page-5



John