Clutch not fully releasing - and shifting problem

[Lucky Phil]

...and my Scura (with the RAM single-plate clutch) shifts flawlessly and is quite happy with clutchless upshifts.

 

My current problem is on the twin-plate LeMans.

 

Phil - does your bike still have the twin-plate?  I think I recall that you were going to install a RAM.

Yes still a twin plater, I'm saving the RAM for the Daytona/V11 engine project.

 

Ciao

[Scud]

I flushed about 3 tanks of fresh fluid through the clutch. Went for a little ride - no difference. Next step, remove engine and pull the clutch plates out.

[Lucky Phil]

I flushed about 3 tanks of fresh fluid through the clutch. Went for a little ride - no difference. Next step, remove engine and pull the clutch plates out.

Bummer:(

 

Ciao

[czakky]

On the bright side atleast you've got other options to ride.

[Chuck]

I'll be interested to see what you learn. The Kid put (I think) that clutch in his Spot along with new springs. The clutch pull was so heavy, we took it apart again thinking maybe a spring had come out of the spring well. Nope. It takes a gorilla hand right back to the lever to release it.

[Scud]

For your entertainment value, here is the mess I have made by pulling two engines at the same time.

 

 

To my surprise, the clutch plates said LGC on them, not SD-TEC. So I checked my invoice from MG Cycle - and it also says LGC. Not only that, the plates are a touch thinner than the lightly used plates I had installed in the Champagne project. I had not ridden the champagne bike, but I did connect everything so I could test the clutch - it seemed to be working, with plenty of free play - and very easy to turn the wheel with clutch in and bike in gear.

 

Here are comparative measurements from the two clutches:

 

                    2002 Champagne    2003 Red

Friction Plates           OEM                   LGC

Miles Used             12,000                 2,500

 

Thicknesses (mm)

Friction Plate 1          7.73                    7.68

Intermediate plate     2.92                    3.21

Friction Plate 2          7.89                    7.64

Pressure Plate           8.07                    7.99

Starter Ring Plate      6.51                    6.44 

 

 

Pushbutton Depth     5.10                     4.09

Pushrod Stick-out   11.02                   11.75

 

 

Interestingly, the biggest differences are the pushbutton depth and the amount the pushrod was sticking out when I removed the engines. The pushrod sticking farther out was not a surprise, because I put a shim in there. But there is a full millimeter difference between the depths of the buttons.

 

I assumed the problem was too-thick plates, but that is not true. I am not sure what to do next.

[Chuck]

Springs too heavy?

[Scud]

Springs too heavy?

 

I think this is part of the problem. Here, I alternated the heavy and light springs, per Gordon's advice. I can compress a light spring all the way (coils touching) with both hands. I can barely get the heavy springs to compress at all by hand. The brightest chrome ones are the heavy springs.

 

 

This is how the pressure plate should look when all the springs are in the wells in both the flywheel and the pressure plate. It should sit evenly and into the flywheel a bit. If even one spring is not in one well the pressure plate will be up flush with the surface of the teeth.

 

 

And given the wear on this new intermediate plate, I think part of my problem could have been that one spring was not properly seated. That would put uneven pressure on the plate and potentially account for this uneven wear pattern. 

 

 

And finally, the push-cup on the left shows signs of friction. I think this is from when I noticed something that felt like the clutch slipping on the freeway - and when I lost all freeplay in the lever. This is potentially what GStallons described in an earlier post - that the shim would cause the pushrod to lose freeplay and bottom-out the clutch slave. That centermost hole is 1mm shallower than the hole in the push-cup on the right. Since I had already shimmed the release bearing, I decided to try the deeper push-cup to compensate.

 

 

So... slipped the engine back in to test the clutch and I am again cautiously optimistic.

 

The lever effort is much reduced (but still not as easy at the RAM on my Scura). With the bike in gear, I can do a two-finger pull halfway to the bar and rotate the rear wheel freely. 

 

Me and some   are gonna go put everything else back together. 

 

I decided not to pull the transmission - partly because I want to (in the name of research) isolate the variables. Besides that, I took a closer look at my spare transmission and it may have a leak that I don't feel like dealing with.

 

I further speculate that the springs are so heavy, and the clutch line is so long, that the line may have been expanding a little, thus requiring more fluid to release the clutch - hence the gorilla-full-pull to the bars with 10 heavy springs and the normal-man-two-finger-half-pull with 5 heavy and 5 light springs.

[Scud]

About 200 miles today and I'm happy to report that the clutch is now excellent. I included some long-hauls on slab, since that's where I lost lever free-play before.  I did a lot more clutchless upshifts, which work very well - and so do clutchless downshifts in the upper gears with just a bit of throttle blip.

 

In fact, my 3-4 clutchless upshifts were great, but when I used the clutch for 3-4 I still missed it sometimes. This made me think the problem is not in the pre-selector, but elsewhere.

 

On further transmission inspection, I noticed that the transmission output shaft has some play. I can grab the driveshaft and push it back and forth and see the shaft sliding in out of the rear seal. My spare transmission has no similar play.

 

http://vid1128.photobucket.com/albums/m492/timscudder/v11com%20misc%20photos%20posted/LeMans%20Project/IMG_5940.mp4

 

Could this play in the shaft be causing the 3-4 upshift difficulties? How alarmed should I be about this? Can I run it like that for a set of tires? 

[footgoose]

good to hear. What do you think was the cause then, of the "tight" clutch?

[Scud]

I think the main problem was using 10 heavy springs, compounded by a pretty small amount of free-play in all the parts of the pushrod. I had also assembled the clutch with 10 heavy springs in my Champagne project - and that also took a lot of effort.

 

It's also possible that one of the springs didn't seat correctly - as I explained above. But I had the engine vertical when I loosened the pressure plate and all the springs fell out, so and I didn't check that on disassembly.

 

I think that alternating light and heavy springs is a good solution. In fact, that means I have new heavy springs available if anybody wants them. I had bought 20 for two clutches, but will only use 10 (5 in each).

 

And Chuck - if "the kid" feels like pulling his bike apart, I bet he can get easier clutch effort by going 50/50 on light/heavy springs.

 

And consider this a "bump" for my next question regarding the play in the output shaft. Video at link in my last post.

[MartyNZ]

...I noticed that the transmission output shaft has some play. I can grab the driveshaft and push it back and forth and see the shaft sliding in out of the rear seal. My spare transmission has no similar play.

Could this play in the shaft be causing the 3-4 upshift difficulties? How alarmed should I be about this?

Now you have me worried.

My transmission output shaft has similar end float, but only if nudged with a screwdriver. I can't move it by hand with the driveshaft connected to the bevel box.

I see that the workshop manual shows a shim and "half rests" at the forward end of the shaft, and specific dimensions for the shaft assembly including the bellville washer stack. Gearbox Ch N, Pg 18 refers. Perhaps the answer is in there?

[Lucky Phil]

This float is present on the 2 gearboxes I have, the one in service and my good spare. This output drive shaft float wont have any effect on the shifting as its simply a spur gear driven shaft with a shock absorbing coupling.

 

Ciao

[Scud]

Thanks Phil. My Scura has a smaller amount of play and the box on the Champagne project has no play - like my spare.

[czakky]

Mine has a bit of play too.