Slipping clutch

[JannPedersen]

First, please bear with my poor english, since I'm from Denmark.

This is my first V-Max, bought a little cheap, as it had been neglegted for quite a long time - and had a lot of issues. But since I enjoy working on motorcycles, this was ok. But now I face a problem I never have experienced before with a hydraulic operated clutch:

The clutch seemed to be kinda "tight" - as when I loosened the grip it engaged quite late on the travel, almost at the far end. And when I gave it a little throttle the clutch slipped immediately!
I would very much like the clutch to engage at about 3/4 of the travel away from the handlebar.

What I have done so far:
New EBC plates (even though I discovered the old ones were within the tolerances), new EBC reinforced clutch diaphragm spring, new oil (Motul 5100 10W-40 full synthetic).

After this - no difference in behaviour!

Clutch lever has several milimeters freeplay. Master cylinders pushrod seems ok. Fluid is brand new.

Of course I have considered the Double Diaphragm clutch spring modification which (maybe) would solve the slipping issue, but as I see it in that way I would treat symptoms rather than cure the course of the problem.

Has anyone experimented with shortening the two pushrods that transfers the force from the release cylinder to the clutch center?

So, dear members - what to do about the travel distance/engaging problem??? Any advice would be greatly appreciated.

 

[Fire-medic]

Usually due to a leak somewhere, either the master cyl or the slave cyl. are the two usual culprits. When air gets into the system, it acts like you described. If you bleed the system, and it soon returns to the same symptom, you have a leak. Place some paper under the area of the left footpeg and see if you get oil on the paper.

https://www.vmaxforum.net/threads/clutch-slave-cylinder-replacement.45011/
The OEM clutch spring dies a good job for nearly all riders. If you abuse the clutch or have power-adders, then a DD clutch may help once the friction plates are worn.

Do not alter the clutch pushrod distance!

One thing some riders have found using aftermarket master cylinders/levers, is that causes issues with the proper clutch operation. Depending upon the cause of the issue, some have either drilled a deeper hole in the lever, or ground-down the lever pin to gain needed free-play. If you have OEM master cylinders and levers, none of this in this paragraph is necessary.

 

[MaxMidnight]

The clutch does tend to engage quite aways out as I recall which can be an issue with those blessed with short fingers.
Have you checked that the push rod (#3) at the lever is the correct way round?


Also make sure that the m/c piston is fully returning when the lever is released.
If it was air in the system I'd have thought you would have a soggy feeling and dragging clutch.

 

[JannPedersen]

Usually due to a leak somewhere, either the master cyl or the slave cyl. are the two usual culprits. When air gets into the system, it acts like you described. If you bleed the system, and it soon returns to the same symptom, you have a leak. Place some paper under the area of the left footpeg and see if you get oil on the paper.

https://www.vmaxforum.net/threads/clutch-slave-cylinder-replacement.45011/
The OEM clutch spring dies a good job for nearly all riders. If you abuse the clutch or have power-adders, then a DD clutch may help once the friction plates are worn.

Do not alter the clutch pushrod distance!

One thing some riders have found using aftermarket master cylinders/levers, is that causes issues with the proper clutch operation. Depending upon the cause of the issue, some have either drilled a deeper hole in the lever, or ground-down the lever pin to gain needed free-play. If you have OEM master cylinders and levers, none of this in this paragraph is necessary.

If air gets into the system, you get a spongy feeling, right? My clutch feels the quite opposite (don't know the term), and from my experience/humble knowledge I believe I can say this is NOT the matter.
(And, the entire motor is desert-dry on the outside).

As mentioned, the freeplay in the clutch lever/pushrod is perfect. I suspect the problem lies where freeplay in the Release cylinder/pushrod/clutch center is missing, but...what can cause that?

 

[JannPedersen]

The clutch does tend to engage quite aways out as I recall which can be an issue with those blessed with short fingers.
Have you checked that the push rod (#3) at the lever is the correct way round?

View attachment 84970
Also make sure that the m/c piston is fully returning when the lever is released.
If it was air in the system I'd have thought you would have a soggy feeling and dragging clutch.

Since I'm 185 cm high and my body's proportions are quite average, I am not "blessed with short fingers"!
My concern is that the feeling of the clutch lever is not "right", and the thought of a clutch that is never truly engaged bothers me a lot.
I think you might have a point though, regarding the idea that one or both pistons for some reason are not fully returning when the lever is released. I suspect that COULD build up pressure in the hydraulic line, so that there is always tension on the clutch pushrod (the ones inside the clutch) - does that theory make any sense???

Anyway, I'm ordering overhaul kit for both the master and the release cylinder...

 

[Fire-medic]

Make sure the small hole closest to the banjo bolt for the master cyl hose is clear of any obstructions. On the floor of the master cyl is a small hole and a noticeably larger hole. Debris in that hole builds pressure that doesn't release.

The other thing is the inner lumen (the pathway) of the hose has deteriorated, collapsing internally. I've had it happen on bikes, cars, and trucks over 55 years of vehicle maintenance. Hose replacement is indicated.

 

[MaxMidnight]

Since I'm 185 cm high and my body's proportions are quite average, I am not "blessed with short fingers"!
My concern is that the feeling of the clutch lever is not "right", and the thought of a clutch that is never truly engaged bothers me a lot.
I think you might have a point though, regarding the idea that one or both pistons for some reason are not fully returning when the lever is released. I suspect that COULD build up pressure in the hydraulic line, so that there is always tension on the clutch pushrod (the ones inside the clutch) - does that theory make any sense???

Anyway, I'm ordering overhaul kit for both the master and the release cylinder...

Have you checked the lever push rod? It DOES make a difference - I know this form experience!

I've not come across a slave cylinder sticking so unless it is corroded up I would think that is unblikely to be the culprit.

We have had instances of the m/c piston not fully returning and building up pressure in the line.
The easiest way to see if this is the case is to crack the bleed nipple and see is fluid is pushed out.

 

[JannPedersen]

Make sure the small hole closest to the banjo bolt for the master cyl hose is clear of any obstructions. On the floor of the master cyl is a small hole and a noticeably larger hole. Debris in that hole builds pressure that doesn't release.

The other thing is the inner lumen (the pathway) of the hose has deteriorated, collapsing internally. I've had it happen on bikes, cars, and trucks over 55 years of vehicle maintenance. Hose replacement is indicated.

It's so funny you should mention that.

Yesterday after writing my last reply, I ordered overhaul kits for both cylinders. In order to prepare for the upcoming task I would drain and disassemble the system. As previous mentioned the fluid was supposed to be brand new (as I was told by the seller of the bike). But when I got the lid off the fluid reservoir, I could instantly see that the fluid was NOT fresh and clear! I made a water content test with an electronic tester; the reading was <1% water though.
Then I pulled the lever to see how much fluid would squirt upon fast release of the lever, and here comes the interesting part:
No fluid seemed to return to the reservoir - not even a slight little movement in the fluid!
The hole in the bottom seemed not blocked, as I through the hole could see the seal and piston move. I then tried to pull and fast release the lever a few times, and suddenly dirt began to appear in the fluid. I repeated the fast lever movement a lot of times, and more and more dirt appeared and suddenly also actual movement in the fluid itselv.
After doing so for about 10 minutes I connected my brake vacuum suction tool to the bleeder valve screw, sucked the fluid out and continuously refilled the master reservoir in order to prevent air to enter the system. When I had refilled about 1/2 liter, I was sure the entire system had been flushed thoroughly. Then reassemble the lid on the reservoir and test actual clutch movement:
Now the clutch engages when the lever is approximately 1/2 ways away from the handlebar!!! Yay!

So, all in all a valuable lesson learned about impurities and dirt in the system. I'm still going to overhaul the cylinders as soon as the kits arrive, though. And the entire system will be cleaned and blown through with compressed air.

Thanks for your advice - which I read this morning - that confirms my experience from yesterday.

 

[JannPedersen]

Have you checked the lever push rod? It DOES make a difference - I know this form experience!

I've not come across a slave cylinder sticking so unless it is corroded up I would think that is unblikely to be the culprit.

We have had instances of the m/c piston not fully returning and building up pressure in the line.
The easiest way to see if this is the case is to crack the bleed nipple and see is fluid is pushed out.

Actually I did try and release the bleed nipple, and as you mentioned the fluid WAS under pressure and came out instantly.
I did check the master cylinder pushrod; the freeplay is several milimeters. That in itself is ok, BUT as you mention it could also indicate that the piston doesn't return fully...
The main (but not necessarily the only) reason for the problem though, seems to be dirt somewhere in the entire brake line. (Please read my reply to Fire-medic's reply).

Thanks for your advise, it's much appreciated.

 

[Fire-medic]

Doing a reverse-bleed, the column of brake fluid you get when the line is clear of debris and obstructions. The tiny little bubbles are the last of air entrapped in the system. Why is a reverse-flush using a syringe from the bleeder valve so effective in removing air from the system? A simple principle of physics: bubbles rise.

Then there's Guiness. Irish mathematicians explain why Guinness bubbles sink (w/ video).

 

[MaxMidnight]

I'm still going to overhaul the cylinders as soon as the kits arrive, though. And the entire system will be cleaned and blown through with compressed air.
Thanks for your advice - which I read this morning - that confirms my experience from yesterday.

I'm a great believer that if it ain't broke don't fix it. Your choice of course but I'd be inclined to put the seals 'into stock' until they are needed...or not.

Also suggest that you try reverse bleeding i.e. bottom up rather than the conventional top down.
You do need to keep an eye on the resevior fluid level though.

 

[JannPedersen]

Today I felt for the first time the thrilling and exciting feeling of what it really means to be a V-Max owner; The V-boost without my clutch slipping!
Genuine madness and ferocity beautifully wrapped in metal and plastic!

Oh man this is truly a bike for the not faint-hearted - and I love it!

 

[Jerry Klay]

View attachment 84979

Doing a reverse-bleed, the column of brake fluid you get when the line is clear of debris and obstructions. The tiny little bubbles are the last of air entrapped in the system. Why is a reverse-flush using a syringe from the bleeder valve so effective in removing air from the system? A simple principle of physics: bubbles rise.

My

 

[Vulcanmax]

Today I felt for the first time the thrilling and exciting feeling of what it really means to be a V-Max owner; The V-boost without my clutch slipping!
Genuine madness and ferocity beautifully wrapped in metal and plastic!

Oh man this is truly a bike for the not faint-hearted - and I love it!

Amen brother. They are a handful. Mine is a stock 97’ and very scary. I love it.

 

[Fire-medic]

Today I felt for the first time the thrilling and exciting feeling of what it really means to be a V-Max owner; The V-boost without my clutch slipping!
Genuine madness and ferocity beautifully wrapped in metal and plastic!

Oh man this is truly a bike for the not faint-hearted - and I love it!

The riders who seem to be most surprised by the Gen 1 are the V-twin riders, especially those who owned Shadows, Vulcans, or Viragos. The 500-750/800cc bikes are plodding, utilitarian transportation devices styled like the famous Harley-Davidsons, but without typical large-displacement 'get-up-&-go.' The 1000-1100cc V-twins have more torque, so it helps to camouflage their lack of rpm 'headroom.'

Switching to a V-4 is a revelation in performance for these folks. I don't think there's a time I've ridden my VMaxes where I haven't seen the red lamp flicker-on (this is a slight exaggeration). That's part of the fun of a 'Max, I don't care what it is up against, it surprises many, and once it's squared away after dealing with deferred maintenance of prior owners, they're pretty reliable.

I've read a few articles about how by the time a used car gets to its third or more owner, the cost of repairs means that things either get done poorly, or not at all. German cars are especially susceptible to this. How many of you have seen 'cars brought into the shop?' Pictures of bodged repairs, leaks fixed with epoxy, calking, duct tape, whatever? Disc brake rotors worn through to the vented hubs, vacuum cleaner hose for exhausts, wire hangers used in-place of nuts and bolts? Maybe we should start a thread of incredible 'repairs' or worn-out parts on bikes.