GSX1100 EFE hydraulic clutch conversion

[Dezza]

As requested by a couple of members, here is a brief description of the hydraulic clutch conversion for the 1100 efe motor. My engine is in a Harris Magnum 2 frame so I have beetter access than on a bike with a cradle frame. The conversion is exactly that which is described in the May 2017 issue of Practical Sportsbikes pp.90-91. Many people on this forum are obviously subscribers to this rag. The article lacks much detail and I will attempt to resolve this. The parts used are the same as described in PS - most importantly, the slave cylinder is the new Frando item, available fron Venhill at a not exactly bargain basement price of £92 quid A Magura unit is also available but this does not work with normal brake fluid, so when using these you are forced to use the ugly and expensive Magura master cylinder.

First, here is a pic of the new slave cylinder. It's clearly a quality item. The unit does not have an integral bleed nipple and relies on a bleed nipple banjo bolt. This is supplied (zinc plated). I had a stainless Goodridge one in the shed so I used that. The threads on the slave are 10 by 1mm (fine pitch).

 

 

 

Edited May 23, 2017 by Dezza

[Dezza]

On the operating end of the slave is a ferrule to fit into a clevis. This is high quality stainless steel an has an external diameter of 6mm. The recess in the end of the ferrule is 3mm, and 3mm wide. The threaded stainless rod coming out of the unit is 3mm, and has a 3 by 0.5 mm thread and llocknut.

 

[Dezza]

The stock clevis of an EFE, Katana etc. is permenantly attached to the clutch cable (1st pic). Unless you want to destroy an expensive difficult to replace OEM cable, you will need a new clevis. I had one from a GSXR 750J rear brake in the shed so used this. The hole is 6mm. The GSXR clevis is beefier than the EFE clutch item so needs a longer pin.

 

 

[Dezza]

AS desribed by PS, the slave has an 8 by 1.25 threaded post designed to screw into the stock mounting boss for the cable adjuster on the crankcase. However, on the EFE this is impossble because the body of the slave cylinder is too wide.

 

[Dezza]

A mounting bracket therefore needs to be made. Obviously this alters the angle the rod will pull the clutch actuation arm but there is no way round this. I found the best way forward was to position the slave to the left of the mounting boss. This was achieved by using as a mount an 8mm bolt.

Edited May 23, 2017 by Dezza

[Dezza]

Next is attaching the operating rod of the slave to the new, GSXR 750 clevis. This involves first cutting a small rectangle 15 by 12 mm of 3mm alloy and drilling and tapping in the middle a 3 by 0.5 mm thread to accept the thread of the operating rod. I did not use the ferrule for this but afterwards found out that cutting a 3mm groove into a bit of metal the same size enabled the groove of the ferrule to be slid in then held in place once it all went into the back bit of the clevis. The pics are of attempt one. I'll get some pics up soon of attempt two, which works better.

Edited May 23, 2017 by Dezza

[Dezza]

Before the clevis is attached, the unit needs to be put onto the new mounting bracket (you can just see this on the far right of the last pic above). The whole unit can now be mounted on the bike. I adjusted it so there is no free play. There is some give in the new parts, mainly because mounting the unit at the optimal angle using the existing threaded boss is impossible unless the threads are drilled out. The master cylinder and the hose can now be attached and the sytem bled. I don't work for PS so will not teach grannies to suck eggs and will assume that people on the forum know how to bleed simple hydraulics like this

Edited May 23, 2017 by Dezza

[Dezza]

Conclusions - first, after bleeding, the clutch works as before but it is NOT noticeably lighter in operation. This undermines the whole point of this project and to state I am dissappointed is an understatement. I have spent much cash, added complexity and weight to the machine for no obvious tangible benefit except that now I have a span adjuster on my clutch lever. The proof of the pudding is in the eating and I have yet to ride the machine after this mod so I will report back. However, before starting I measured the pull of the lever with a fishing balance and it went off the 25 pound scale with the stock cable when pulled in; the same thing happens with the hydraulic conversion so it's still fucking heavy but I need another balance for an accurate measurement. Maybe I should take up fishing though.

 

Second, cutting a slot in a small metal plate gives a more secure fitting for attaching the slave rod to the clevis. I'll try and put some pics up soon.

 

Third, I think PS get sent stuff free and are then economical with the truth in some of their articles to keep the supplier of the freebies happy. If they had stated it makes little difference in the weight of the clutch pull I would have bought some fancy clutch perch for the cable instead and tried that.

 

Fourth, why hasn't anyone invented a geared clutch perch for classic bikes with heavy cable clutches?

Edited May 23, 2017 by Dezza

[bluedog59]

Maybe a change of master cylinder bore would sort that. Am I right in presuming the slave pulls the clutch arm ?  

[Dezza]

1 minute ago, bluedog59 said:

Maybe a change of master cylinder bore would sort that. Am I right in presuming the slave pulls the clutch arm ?  

Yep, that's right Rob the slave pulls the cluch arm. I used the master cylinder recommended by Venhill and used in the PS article. On the Venhill website it states a 17mm m/c but the unit is actually 16mm, which should make the clutch lighter than using a 17mm unit. Going for a smaller bore mc, if available, would lighten the clutch but then it may not disengage fully.

[Gixer1460]

Its a nice 'pretty' solution that seems not to have been correctly executed! I'm guessing a 14mm master would work better if all the other slack levers and linkages were removed. The GSXR solution of through the shaft works directly - no slack. With the above arrangement you have potential slack in the slave to clevis, clevis to lever, lever shaft rack to pusher rack and pusher rack to thrust bearing and hub so you end up having to create more movement to take up the tolerances.

Answer is become a gorilla and / or grow some man fingers. Alternatively, lighter springs and a lock up may ease the pain!

[Dezza]

1 hour ago, Gixer1460 said:

Its a nice 'pretty' solution that seems not to have been correctly executed! I'm guessing a 14mm master would work better if all the other slack levers and linkages were removed. The GSXR solution of through the shaft works directly - no slack. With the above arrangement you have potential slack in the slave to clevis, clevis to lever, lever shaft rack to pusher rack and pusher rack to thrust bearing and hub so you end up having to create more movement to take up the tolerances.

Answer is become a gorilla and / or grow some man fingers. Alternatively, lighter springs and a lock up may ease the pain!

The mechanism as it is does not have play as this can be adjusted out. The new slave also does not move because the bracket is made of 6mm alloy. The gear is sold as lightening the clutch action, which it does not do, at least not obviously. A GSXR clutch has only 4 springs if this is what you mean, a GSX clutch has 6 springs so a GSXR clutch may be inherently lighter to operate than a GSX clutch. A lock up clutch may be a solution though. I suspect using a 14mm m/c would result in a lighter clutch action but also clutch drag.

 

'Growing man fingers' isn't a particularly constructive suggestion for me, as the problem lies in my injured left shoulder/arm/hand after an independent series of accidents from 1970 to 2008. This has included amongst other things breaking my left collar bone 6 times, and a left scaphoid fracture that took 6 months to heal. The culmulative effects of all this means my left grip is significantly weakened.

[jimbo22]

Too bad. I had this conversion on the list as I also find the clutch to work very badly. I had a GSX1200 Inazuma with hydraulic clutch- it was perfect. Now I switch from ZRX1200R (also hydraulic) to GSX750S, and the difference is very big. 
I did all I could after putting the GSX750S together to make the clutch work as light as possible (disasembled the shaft in the engine cover, put new bearings, made sure it's super light, oiled the clutch cable). 

It turned out that it makes a big difference if the handlebar is straight and turned left (when on stand). So that's a plus - during riding, it's not that bad... but in line splitting and heavy traffic, I already know that the hand will be tired quickly:)

Looking forward for new details if You figure something out.

Edited May 23, 2017 by jimbo22

[Captain Chaos]

the clutch cable on my mate's EFE was not new anymore which caused heavy clutch operation. I lubed the cable, it improved a bit. Then later I installed a new cable and that made a massive difference.

First thing I recommend if the clutch is too heavy, is a new clutch cable.

[Gixer1460]

3 hours ago, Dezza said:

The mechanism as it is does not have play as this can be adjusted out. The new slave also does not move because the bracket is made of 6mm alloy. The gear is sold as lightening the clutch action, which it does not do, at least not obviously. A GSXR clutch has only 4 springs if this is what you mean, a GSX clutch has 6 springs so a GSXR clutch may be inherently lighter to operate than a GSX clutch. A lock up clutch may be a solution though. I suspect using a 14mm m/c would result in a lighter clutch action but also clutch drag.

'Growing man fingers' isn't a particularly constructive suggestion for me, as the problem lies in my injured left shoulder/arm/hand after an independent series of accidents from 1970 to 2008. This has included amongst other things breaking my left collar bone 6 times, and a left scaphoid fracture that took 6 months to heal. The culmulative effects of all this means my left grip is significantly weakened.

Wasn't a dig and sorry for the messed up arm which probably isn't helping with needing a lighter clutch - it may be a bit better but not enough for you?

If you take ALL the slack out of this type of mechanism you'll burn plates - the plates need to expand when hot ...... no slack and it'll drag! A GSXR may have 4 springs against 6 of the GSX but it also has 2 more plates and handles 25 - 30 more HP - this may indicate a GSX clutch is over sprung?

[Dezza]

35 minutes ago, Gixer1460 said:

Wasn't a dig and sorry for the messed up arm which probably isn't helping with needing a lighter clutch - it may be a bit better but not enough for you?

If you take ALL the slack out of this type of mechanism you'll burn plates - the plates need to expand when hot ...... no slack and it'll drag! A GSXR may have 4 springs against 6 of the GSX but it also has 2 more plates and handles 25 - 30 more HP - this may indicate a GSX clutch is over sprung?

Ok, thanks for the suggestions. It's interesting to know that GSXRs have extra plates. Anyweay, I have not road tested the bike yet so obviously it will need tweaking when hot etc. I am hoping things are at least better than before though!

[bluedog59]

Try moving your clutch arm and adjusting it so the range of movement is equidistant from the arm at 90 deg. It looks in the picture like it is soon into a falling ratio at the moment.  

[Dezza]

2 hours ago, Captain Chaos said:

the clutch cable on my mate's EFE was not new anymore which caused heavy clutch operation. I lubed the cable, it improved a bit. Then later I installed a new cable and that made a massive difference.

First thing I recommend if the clutch is too heavy, is a new clutch cable.

Yep, I agree the first port of call is to check the cable. I have owned this bike for 30 years and it still has the original clutch cable but it is in very good condition and has been well-maintained. Although it has 'taken shape' through being differently routed to that for which it was originally designed there are no sharp kinks in it. If things have not improved significantly though, it will go back to a cable operated clutch with a new cable as there is no point in increasing complexity for no gain. I am a firm beliver in keeping things as simple as possible.

[Dezza]

2 minutes ago, bluedog59 said:

Try moving your clutch arm and adjusting it so the range of movement is equidistant from the arm at 90 deg. It looks in the picture like it is soon into a falling ratio at the moment.  

Yep, I thought of that. Any further out (one more spline in fact) and the arm fouls the frame tube. I blame Harris (both of them)

[bluedog59]

So the slave needs to got left (clockwise) instead. Must be something we can do here.

[Simbec1863]

Cracking job fitting it Dezza and disappointing that you have found no benefit from this mod, was watching in anticipation as I have the same need with my ET and a similar knackered wrist and as you say the mag made it sound like it was all good...

I fitted a brand new cable recently but this was only slightly better, its also noticeably better after the annual oil change for a few weeks, but then returns to it's old self.

Hope you get it sorted will be watching in hope for a good result that I can copy

[Dezza]

1 hour ago, bluedog59 said:

So the slave needs to got left (clockwise) instead. Must be something we can do here.

I have just put the tank and seat back on so if you are around between now and Thursday I can bring it over for an examination if you like

[bluedog59]

I'm about tomorrow, text me in the morning.

[Pedda]

Several ways of conversions to be found here:

http://www.katana-treff.de/viewtopic.php?f=9&t=444

German katana site. Best option is the full hydraulic conversion imho. 

[Pedda]

This very nice oss bike got that fully done mod, btw.