Topic: Barnett Clutch Lever Stiffness and Clutch Issue

[Solowerks]

The original clutch installed on my 77' 550 was slipping at higher RPM (otherwise did not noticeably slip) so I decided to buy a replacement Barnett clutch to resolve this issue. 

Upon removal of the original clutch, I was surprised to find that it did not appear to be worn requiring replacement.  Since I had everything apart already I decided to install the new Barnett clutch setup. 

Upon completion and test ride, I found the force to pull the clutch lever in significantly increased to the point that it wasn't comfortable at all to ride. I also couldn't adjust the clutch enough to allow disengagement for smooth shifting, getting into neutral.

I did some research and found that the Barnett springs are ~10% stiffer than OEM ( according to random sources), so I decided to swap the springs back to the originals.  Now the clutch slips very very badly, but the lever is comfortable, like it was before.  Note:  I did not disassemble the Barnett clutch pack when swapping the springs so I don't think that I disturbed anything inducing the slip problem.

I'm at a loss as to what to do right now, and ultimately may reinstall the original clutch and live with the high RPM slip...At least I could ride the bike!

Regarding the Barnett clutch system, I noticed the #7 plate provided was the thinner thickness, and when I installed the pack together there was a small gap.  I decided to use the original #7 thicker plate which appeared to assemble together without the aforementioned gap. I have no clue how you would ever get the clutch to function correctly with the thinner plate and ~ 1/8" gap.

Should I try installing the thin #7 plate with the Barnett springs? 

My conclusion right now is that the #7 thicker plate has nothing to do with the slippage since it did not slip with the stiffer springs.

I'm also under the impression that the spring stiffness may be needed for the Barnett clutch to grip, but there's no way I can live with the lever issue!

I asked the guy that sold it to me and he said to use all the Barnett components since it was designed to work that way.  I don't believe him based on the gap issue.  I also don't think this would have resolve the lever force issue.

Any advice would be greatly appreciated.  Thanks!

[ekpent]

 I guess I will be the first to ask but how long have you owned the bike and what kind of oil are you running in it as far as brand and weight ? Any friction modifiers in it ?

[Solowerks]

Running full syn 10-40 for 4-stroke wet clutch engines.  Typically change it every 1k-1.5k maximum.  Probably don't ride more than this in a year.

It slipped from day one when I bought a few years back.

I did add Lucas to the oil two changes ago, but with/without I didn't notice any increase or decrease in the amount the clutch slipped.  The engine ran noticeably smoother with the additive.

[PeWe]

+3 for correct oil. Not car oil in general.
JASO MA on the label means for wet clutch.  This is what you need.

Your oil might not have that on the label. Maybe car oil full of antifriction stuff which a car engine without clutch and gearbox like.

JASO MA2 has most likely less good zinc and phosporous our old bikes needs.

Read here:
https://www.rymax-lubricants.com/updates/what-does-the-jaso-oil-specification-mean/

One of my CB750 has the stiffer Barnett springs for CB550. It has -66 in its partnumber. (66 ft lbs).
This to ensure no slips due to much more torque than stock.
Clutch metal plates glass beaded too.

It is a little stiffer than Barnett springs for CB750 that has -56 in its part number. (56 ft lbs).
It might feel different on a CB750 than 550
The routing of clutch cable an important detail.

A slippery clutch like that can indicate wrong oil.
Synthetic work fine as long as it is motorcycle oil.

What is Lucas additive? That's an oil brand making lots of stuff.

I noticed that an additive for more zinc and phosporous contained antifriction stuff so I could not use it, (Edelbrock). That was for US vintage cars, old V8....

[Solowerks]

Lucas Heavy Duty Oil Stabilizer.   I had some in the garage and tried a half qt.  It didn't make things any worse, in fact perhaps better.

Regarding the oil type, are you referencing the slip at high RPM or the slip after installing the original springs with the barnett clutch?  I could see the high RPM slip being oil....

What I'm planning to do is reinstall the original clutch with the original friction plates, but scuff them up a bit if this makes a difference at all long term - probably not. 

The oil I bought recently was Mobile 1 Racing 4T, but in the past I likely have used conventional syn oil.

The barnett springs are noticeably stiffer and taller.  The cable routing hasn't been changed and with the original springs feel fine. 

Thanks for the article.  I'll have a read. 

[PeWe]

The Barnett clutch is designed to be used with their springs.
The springs can be one of the issues causing slip.

I do not know CB550, but CB750 often use stock clutch with Barnett springs.

My tuned bike use EBC clutch and the stiffer Barnett springs  (550 model).
My stock bike cheaper clutch from Cruzinimage with Barnett CB750 springs.

The only thing I have read about Barnett clutch is it can be grabby at take offs. Or dragging.


EDIT:
More ideas when searching
http://forums.sohc4.net/index.php?topic=180823.0

http://forums.sohc4.net/index.php?topic=3380.0

[Solowerks]

How does the lever feel on your 550 with the Barnett springs?  I take it nothing notable to report. 

I'm wondering if they sent me the wrong springs. There's no way this is considered street-able the lever pull is so hard. 

Everything came loose in a box to me and not in one neat kit. I think I tossed the original packaging the springs came with too. 

[PeWe]

The harder Barnett springs (For CB550/500.....) my CB 750 K6 has are black and 36.6 mm long. (Springs are used before measure)

The golden ones are Barnett CB750 springs which are softer.

Clutch can work better after some use.
My clutch was horrible the first rides this year.
I had it apart this winter, glass beaded the discs.
The package had to be used, all discs centered or whatever made clutch to be horrible hard, not cable routing.

The top link in my previous reply is about same type of clutch you have in a CB550.

[Solowerks]

If anyone is reading this at a later date and time - Buy the Honda OEM Clutch if available. 

[Solowerks]

Inspected the original friction plates.  They are right at the serviceable limit of 2.4mm.  Reinstalled.  Fresh Oil.  She now rips once again. 

End of this month long fiasco....