Lighter Clutch Pull Wanted

[bondo]

We have an '08 DE 300 we bought this summer to replace an '05 DE 200.

One thing about the 300 we miss from the 200 is the clutch pull effort.
The '05 was a one finger pull (about like a trials bike) and was one of the things we loved about the bike. The '08 has a lever effort about like a KTM, not bad at all, but nowhere near as nice as the wonderful '05.

My question is how can we get to that one finger clutch action on the '08.
My understanding of clutch lever pull effort is that it is a direct function of the size of the piston / fluid orifice in the master cylinder - smaller orifice equal easier lever pull. Correct?

If that's true, what are the benefits / problems associated with a smaller v. larger fluid orifice in the master cylinder?

Also, does anyone know whether the hydraulic hose on my '08 will connect to an '05 master cylinder? Does anyone have a good '05 clutch master cylinder/lever assembly for sale . . .cheap?

Comments? Suggestions?

 

[GMP]

Something is not right. They all should have light pulls. I'd go through the system and check everything. Cruiser fought something like this for a long time on his '03.

 

[marjastaja]

What is the difference between DE and EC?

 

[Cruiser]

The best result I had was rebuilding the slave cylinder,, The O-ring was effed up and caused most of the binding.. that and my clutch housing was a little warped.. due to a Knight brand slave cylinder guard.. Changed out the slave and did not reuse the guard and it was much better.. I also rebuilt the MC,, swapped it out to the old 97's MC and tried one from a 2001.. also changed over to a braided hose from EE for a KTM 200,, not sure on year but it fit well.. And even had the entire clutch basket out at least a dozen times..
Good luck and it should be in your hydraulics.. they are super easy to rebuild too,, just messy..

 

[bondo]

Thanks for the input everyone. This bike has about 100 hours on it, but everything in the clutch actuation system appears to be in pristine condition
(at least externally). The bike has a braided stainless hose on it.
Other than the pull effort, everything seems to perform as normal.
I'll double check the brand of the master cylinder, but I think it may be a Domino unit. Is this stock eqpt. on the '08's (I seem to recall the '05 used a Magura master cylinder). The unit i have calls for mineral oil as the hydraulic fluid, whereas the '05 unit called for DOT 4. Can't imagine that the type of fluid would have any effect on my issue.

 

[Berkyboy]

As far as I know AJP is the OEM manufacturer for GasGas hydraulic clutches on all enduro models since they started building their own engines in the latter part of the 1990's.

Make sure that the clutch master cylinder plunger, where it comes in contact with the lever, has a little free play.

Just under an 1/8th of an inch is necessary to allow the clutch hydraulic circuit to work properly.

 

[bondo]

Yep, the free play in the lever is just about right. We have no complaints with the operation of the system. The entire clutch system, both the hydraulic and mechanical components, function perfectly. The feel and function of the system is very consistent, hot or cold, abusing the clutch or not, we've got no issues with the functional aspects of the system
Our only complaint is with the lever effort. Frankly, if it were any bike but a GG, I'd consider it perfect.

 

[roostafish]

My bike has the Magura clutch master cylinder, and the lever effort is much like a KTM. The AJP stock one is much lighter, however, this was swapped out to get the clutch to completely disengage and not creep in gear. This was done by our webmaster, so I'd have to ask him if the fluid is different. I love the light pull of the AJP, but I wouldn't trade it back to have it drag in gear again.

 

[Cruiser]

I'm curious why the mc was changed out to fix the drag,, the drag issue is a mechanical clearance issue in the clutch basket,, is the volume of that master different? I used a very thin shim in my 07 to fix the drag issue(from steve@motowest) which was a valve adj shim I believe? Which if I remember correctly basically lengthened the pushrod .020" allowing the basket to fully release the plates.. Worked great.. no extra effort..

 

[Cruiser]

Bondo,, what Berkey was getting at is if the lever does not have free play the piston/plunger will not come out enough to clear one of the internal ports and this has been a cause of stiff lever feel in the past.. Probably not the issue you have but may be.. Does you MC have any #'s? The Domino I believe is for the trials bikes.. might not be the right diam piston/plunger you need..

 

[gasgasman]

Here's the clutch master cylinder overhaul steps.

 

[GMP]

With hydraulics you trade leverage for travel. So, with the same size slave, if you increase the volume of the master, you will increase slave(and clutch pressure plate) travel with the same lever travel, but increase effort as well. The reason for allowing free play in the master is to allow the piston to fully return, to provide the full stroke and volume. If adjusted wrong(no free play) you may not get full slave travel and the clutch may drag, but lever effort should not be affected.

Do as Cruiser said and check that slave o-ring first. His was brutal stiff compared to mine, and I remember it had a strange feel like it was bottoming out at the end of lever travel.

Assuming the master cyl is correct it can only be one of two things, friction or excessive spring force(unlikely).

 

[Cruiser]

Bondo,, where are you located?? if your anywhere close by I can lend you some parts for testing..

 

[skid jackson]

Interesting ....
I just replaced the O ring on my slave that seals it to the out side on the outside chance that it was where water was getting into my tranny. It did not appear that was the case. A few weelks befoer a friend said he thought my clutch pull was a little heavy and he thought it used to be easier. I hadn't thought about it but agreed. He said I should change out the mineral oil and it would probably get better. As mentioned above new outside (case O ring) and new fluid ... still seems a heavy pull to me. I'll check the free play but I don't think that is an issue

 

[bondo]

Haven't been on the computer all weekend. Just reviewed all of the latest input. Thanks to all for the very enlightening and useful feedback.

Over the weekend, I looked over the bike and yes, the master cylinder is the AJP unit with the dark green cover. Also, decided to inspect the slave cylinder.

The outer o-ring on the slave cylinder piston(the unit has two) was a little beat up and there was some dirt accumulated around it as well. No o-rings on hand, so I cleaned the entire slave cylinder, replaced the mineral oil in
the system, bled out the air and reassembled the unit.

The clutch pull effort is better than before, but still not quite where I'd like it to be. Will try replacing the o-rings in the slave cylinder.

All of the other parts in the slave cylinder and the clutch pushrod where it
meets the s.c. looked like new.

Cruiser, I'm in Birmingham, AL.

GMP - thanks for the quick explanation of the relationship between master cylinder fluid orifice size,
pushrod travel and lever effort.

I'll post the results of the o-ring replacement.

 

[bondo]

Okay all you GG troubleshooters, here's what we did and here's what happened.
As mentioned in my previous post, I found the outer o-ring on the slave cylinder piston to be a little frayed and worn.

I replaced the entire piston assembly, including both o-rings.
We completely replaced the mineral oil hydraulic fluid
(it was messy as was suggested - and now the bike smells like a nursery).

The result was that there has been no perceptible change in the lever effort as a result of our work.

Question: Does the 300 use heavier clutch springs than the 200? My understanding is that all of the lower end components are the same on the 200 - 250 - 300, but perhaps the bigger motor requires a little
stronger spring to keep the clutch from slipping under heavy load.

Ideas and comments welcome.