Topic: Clutch slippage at high speed/revs--best solution

[jessezm]

Howdy folks!  As I'm breaking in my new CB400f/466cc top end, I'm running into a few things here and there.  This time it's the clutch slipping when I'm hot on the throttle in 4th, 5th, or 6th gear to pass a slowpoke on a two-lane road.  It's happened a few times.  I just back off the throttle a bit and it re-engages.  The bike only has 5k original miles, so I'm more apt to think this is a problem of spring strength than clutch wear.  I figure that the big bore and new cam may be pushing the stock springs to their limit.  What would you all recommend?  HD clutch springs?  Shims/washers under the stock springs?  New clutch?  Simple adjustment?  Not too familiar with clutch work.  Thanks!

[Gordon]

Start with adjusting the clutch.  If that doesn't cure it then start looking into other options. 

[Bob Wessner]

Are you saying there is no slippage, in any gear under 4th, under any conditions?

[jessezm]

No, that's just where I've noticed it thus far.

[Bob Wessner]

Sounds like you have a good excuse to go out in front of your house and drop the clutch a few times. Tell your neighbors you are doing important research. 

[jessezm]

Haha!  Can you tell me what I'm looking for, or what it will tell me if the clutch slips in all gears vs. just the 2-3 top ones?

[Old Scrambler]

Bob is having a little fun with you............Your problem is typical..........adjust the clutch thread at the housing........if that does not cure the problem (9 out of 10 it will)........check the oil you are using (recommend SHELL Rotella)........otherwise you may have worn clutch plates. The springs seldom allow slippage unless you have found some serious added HP.  If the fiber plates are worn you will need to replace them.  If the metal plates are warped they will also need to be replaced.

[jessezm]

haha, ok.  I'm using Honda HN4 10W-40.  I'll do the clutch adjustment and see if that makes a difference.

[P_Camps]

hmmm I get the exact same thing on my 550.  I was just gonna go ahead and do a new clutch this winter.

[domer]

i read some where on hear that one way to test the clutch is you put the front wheel against a wall or the like, put her in 5th gear, give a LITTLE throttle (note the "little" part) and slowly let out the clutch. if the motor dies, the clutch is ok. if it doesnt well you know what you gotta do.

disclaimer: if some how you manage to drive your bike up a wall. your an idiot, and its nobodys fault but your own! no offense, just sayin

[MADCB400F]

Hi, I had the same problem with my 466 kit. I pulled the clutch and one of the clutch plates was msg. I then put in a Barnett kit and no problems. Good luck

[MCRider]

i read some where on hear that one way to test the clutch is you put the front wheel against a wall or the like, put her in 5th gear, give a LITTLE throttle (note the "little" part) and slowly let out the clutch. if the motor dies, the clutch is ok. if it doesnt well you know what you gotta do.

disclaimer: if some how you manage to drive your bike up a wall. your an idiot, and its nobodys fault but your own! no offense, just sayin

Yeah that's an old saw for the car guys as well. You really need to give it a little more than a little. Like you were going to pull away from a stoplight fast. If it dies you're OK. But i can't see the point in such a test. If you think for a moment your clutch is slipping, it is. It will not heal itself. You may be able to nurse it for awhile. New springs or tougher springs, or shims will buy some time. Time enough to save up for new plates. 

[jessezm]

Hi, I had the same problem with my 466 kit. I pulled the clutch and one of the clutch plates was msg. I then put in a Barnett kit and no problems. Good luck

Barnett disks and springs as well?  and you're happy with it?  Clutch not too stiff?  I was thinking of doing the same thing.  Should I order a new clutch cover gasket if I'm going into the basket?  I did just put a new one on...

[seaweb11]

Barnett disks and springs as well?  and you're happy with it?  Clutch not too stiff?  I was thinking of doing the same thing.  Should I order a new clutch cover gasket if I'm going into the basket?  I did just put a new one on...

I have a full Barnett set up on one of my bikes.
It is not at all everyday road comfortable, but it sure does get your attention!

[jessezm]

Barnett disks and springs as well?  and you're happy with it?  Clutch not too stiff?  I was thinking of doing the same thing.  Should I order a new clutch cover gasket if I'm going into the basket?  I did just put a new one on...

I have a full Barnett set up on one of my bikes.
It is not at all everyday road comfortable, but it sure does get your attention!

Man, my hand already gets a bit sore riding around town...  Hopefully doing the adjustment will take care of things, but if I have to get a new clutch, are there any more comfortable options?    (are the EBC kits any good?  or just OEM? disks with 550/750 springs?)

[seaweb11]

I used a stock set up on my other bike a few years ago and it still runs fine
Just bought new discs.

[Tim2005]

What I've done to cure this on my 460 is something I read from Kaz Yoshima, take a sheet of quite coarse wet & dry/emery cloth (180 grit maybe, can't remember precisely) and lay it on a very flat surface, with a bit of oil on it. I then rubbed each plain plate around on it in order to kind of give it a cross-hatched surface. It takes ages to do both sides of each plate, and isn't too good for your finger tips, but works a treat. I use stock friction plates with this & stock springs too.

[jessezm]

Cool, I may end up trying that, too! 

[jessezm]

Adjusted the clutch per the book, and took her for a spirited ride.  Sorry to waste everyone's time, that was all it took!  Gotta love those 5-minute fixes!   I could not get her to slip, even pulling 9k rpms up a long hill in 5th...