After a number of attempts fiddling with the master cylinder including bleeding the system and adjusting the master cylinder pushrod and also fitting different levers I figured I needed another point of view.
- Clutch pushrod adjuster at clutch lever.
I contacted Pete Roper who has worked on my bike and which holds a special place in his heart, (private joke) we organised for me to ride down so we could attack the problem.
The symptoms were a sometimes spongy lever, gears clashing and the shift notchy and at times difficulty finding neutral. An obvious indication that the clutch was binding. This was however countered by an occasion where the clutch started slipping ferociously in the middle of a ride for no apparent reason. Obviously not an indication of a binding clutch.
The initial course of action taken by Pete was to have a look at the hydraulic system as this is obviously critical to proper clutch actuation and also the easiest component to access.
After some initial problems bleeding the system there was a thought that the master cylinder was defective but some ongoing evaluation established this was not the case. We proceeded to inspect the remainder of the hydraulic system including the slave cylinder and the thrust mechanism and pushrod.
After determining the whole hydraulic system was in fact sound the thoughts turned to a defective clutch assembly which was a daunting prospect due to the work involved and the likelihood of an unplanned overnight stay at the local motel or pub.
However prior to embarking on the mammoth task of pulling the clutch apart Pete took a step back to have another think about the problem. The bike has only 16,000 km on the speedo, the 8v Griso clutch has a reputation of being trouble free and seems to be bullet proof and I have never a cooked a clutch in my life on a multitude of cars and bikes some of which have had 200,000 km on the clock.
After examining the parts of a new clutch assembly he had in stock and how it operated Pete concluded the sometimes bizarre operation of mine was just not consistent with the clutch assembly failing.
This led us to have another look at the hydraulics where we eventually discovered that the adjustable pushrod pin in the lever that actuates the master cylinder piston was not secured correctly and could be adjusted readily without the need to loosen the locking grubscrew.
Further investigation confirmed that by adjusting the pin we were able to reinstate the correct operation of the hydraulic clutch mechanism which solved the problem of the clutch not releasing cleanly.
Once we established that this was the route cause of the problem the next question was how come the clutch had varied so much from day to day without any outside intervention.
By a process of elimination it was determined that the tiny grub screw which was supposed to lock the master cylinder pushrod pin in place was abnormally loose allowing the adjustable pushrod to wind itself in and out due to the vibration of the bike. This altered the operating travel of the master cylinder piston causing the clutch to sometimes only partially release and also on one occasion cause the clutch to slip.
As I was previously unaware of this grubscrew until Pete pointed it out I had never realised it was not locking the pushrod in place and explained why my previous adjustments only resulted in temporary improvement. Once the pushrod was reset to the correct freeplay and then correctly locked in place allied to the updated thrust component (http://forum.guzzitech.com/forum/196/7725.html ) we put in because we had it apart anyway the clutch and gearbox began to operate to a standard I had never previously experienced.
This fix has transformed the clutch and gearbox to one which I can now say is the sweetest shifting gearbox I have ever experienced.
- Underside of clutch lever where you will see the locking grub screw for the pushrod pin.
Moral of the story – if you are having clutch issues on your Griso or another model with the same clutch lever/master cylinder ensure your clutch master cylinder pushrod is adjusted to the correct clearance and make sure the locking grubscrew is secured correctly.
