Anyone running different carbs.

[Bozo]

I have a 1380cc FJ with the Barnett 82lb (green) springs and a FJR master.
No slip and the clutch pull is tolerable.

Pat, very interesting, I think the FJR is a Nissan Master, my springs are a bit stronger than the green springs (specially made).
I checked the clutch plates and both are in good condition and thickness, so the slip only started when the extra power came into play. Don't forget my slip is only when engine is not to temperature, once in temp it does not slip.
My Standard FJ1200 "Limo" has an extremely powerful totally Std (pods only) motor, it also started to slip (after 110K) when warm but when hot it was ok - it now has a Barnett plate with std springs and even when not at temp it grips. Note I rarely if ever drag a bike not at temp.
On my "evil FJ" with the 14mm Nissan master it is easier (less pull strength) to use but it "grabs" mid way travel. Not a problem as I use this bike for weekend travel and the standard for work (37km one way of work traffic).
I'd love to try the 1380 one day, it must be a torque monster.

[ribbert]

.... totally Std (pods only) motor, it also started to slip (after 110K) when warm but when hot it was ok - it now has a Barnett plate with std springs and even when not at temp it grips.

Bozo, if your standard clutch lasted the first 110k, which is a good innings, why not just replace it and get another 110k, and, you retain the easy action. Also, a set of friction plates is a lot cheaper than a Barnett conversion and a lot nicer to use.

Not wishing to start a discussion on what does and doesn't slip and under what conditions and on what bikes, but the Penrite oil you're using is full synth, and any way you cut it, synth is slipperier than mineral.


With a Barnett clutch, people only ever talk about the increased pull at the lever and ways to lighten it. The other, and equally significant issue is the linear loading of a coil spring vs the over centre feature of a diaphragm spring.
If you have more power like Pat, Frank or your own "Evil FJ" a heavy duty clutch is a necessary evil but it seems such a shame to compromise the light controls of a stock FJ when there's no need for it, such as on a standard well tuned engine.

The entire automotive industry adopted over centre clutch springs for obvious reasons in the middle of last century, fitting a Barnett coil spring clutch unless you absolutely need to is a throw back to era, and am I correct in thinking Frank's 165 rear wheel HP is handled with a no more than a doubled up standard clutch spring? I doubt there are too many FJ's making more power than that.

You say your fibres plates are within spec thickness, they always are, that's not how a wet clutch plates wear. In my 13 years on this forum and reading of owners being told to measure the thickness of their plates I can't recall a single occasion when they were under spec.

Your observation that is slips more when the oil is not up to temp is normal.

Bozo, I know you've already chosen your path, but the above advice was more taking the opportunity to inform readers who might be experiencing the same problem that there is more than one way to fix it. It's always good to have choices.

Noel

[Flynt]

...am I correct in thinking Frank's 165 rear wheel HP is handled with a no more than a doubled up standard clutch spring?

Correct.  Two stock springs and no slips, even when lifting the front in 5th at WOT.  FYI - I run Valvoline VR-1 for it's high zinc content...  recommended for higher lift cams.  Might slip with a synthetic oil??

Frank

[Bozo]

.... totally Std (pods only) motor, it also started to slip (after 110K) when warm but when hot it was ok - it now has a Barnett plate with std springs and even when not at temp it grips.

Bozo, if your standard clutch lasted the first 110k, which is a good innings, why not just replace it and get another 110k, and, you retain the easy action. Also, a set of friction plates is a lot cheaper than a Barnett conversion and a lot nicer to use.

Not wishing to start a discussion on what does and doesn't slip and under what conditions and on what bikes, but the Penrite oil you're using is full synth, and any way you cut it, synth is slipperier than mineral.


With a Barnett clutch, people only ever talk about the increased pull at the lever and ways to lighten it. The other, and equally significant issue is the linear loading of a coil spring vs the over centre feature of a diaphragm spring.
If you have more power like Pat, Frank or your own "Evil FJ" a heavy duty clutch is a necessary evil but it seems such a shame to compromise the light controls of a stock FJ when there's no need for it, such as on a standard well tuned engine.

The entire automotive industry adopted over centre clutch springs for obvious reasons in the middle of last century, fitting a Barnett coil spring clutch unless you absolutely need to is a throw back to era, and am I correct in thinking Frank's 165 rear wheel HP is handled with a no more than a doubled up standard clutch spring? I doubt there are too many FJ's making more power than that.

You say your fibres plates are within spec thickness, they always are, that's not how a wet clutch plates wear. In my 13 years on this forum and reading of owners being told to measure the thickness of their plates I can't recall a single occasion when they were under spec.

Your observation that is slips more when the oil is not up to temp is normal.

Bozo, I know you've already chosen your path, but the above advice was more taking the opportunity to inform readers who might be experiencing the same problem that there is more than one way to fix it. It's always good to have choices.

Noel

Noel, always open to advice, you are right I have never had a plate that was considered worn. I did get plates from new that were a bit under spec width though. The reason I mentioned the plates originally was because I was worried that the slip that was noticed during the dyno might've been there longer which would've caused the steel plates to warp. As you mentioned if I'm worried in the future I always have the twin plates I can put in. I believe Pete (KTMdude) also runs twin plates and not slip (he has a bit more power than my evil one).
As for the Barnett clutch on my std bike, I got that from a guy who no longer needed his new plate for a bargain $50 so fitting it was a no brainer.

[Bozo]

...am I correct in thinking Frank's 165 rear wheel HP is handled with a no more than a doubled up standard clutch spring?

Correct.  Two stock springs and no slips, even when lifting the front in 5th at WOT.  FYI - I run Valvoline VR-1 for it's high zinc content...  recommended for higher lift cams.  Might slip with a synthetic oil??

Frank

Hi Frank, the Penrite oil is noted for its zinc content which is why I use it, so no problems there. Ye I lifted the front in 5th using my bloody jack - hahaha