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Discussion Starter · #1 ·
I need some help/advice/input regarding my clutch, the bike has 17k miles on it and late last year the clutch started slipping. IMO it wasn't terrible, it would slip for a couple seconds when starting out in first gear, and sometimes in second depending on the load. I had never adjusted the cable, and I highly doubt the PO did either. I really didn't think about adjusting the cable until after I dug into the engine to adjust the balancer chain, however I am thinking that the adjustment won't do any good now. The springs are barely above the service limit so they will need to be replaced soon. I was just going to replace them and be done with it, but my friend took a look at the clutch and said I should probably replace all the disks as once it starts slipping, the damage is already done and it will only go down hill from there. He also ran his hand around the basket and picked up one or two 'fibers' and said that the disks were definitely on their way out.

Does this all sound legit or would new springs do the trick? I was going to check the specs on the disks, but I cannot get the locking nut off. I tried the hammer and screwdriver method the manual mentions, but wasn't having any luck and didn't want to chew the nut up. The nearest dealer doesn't have the tool available and $50 online seems quite high for something I might use once or twice. Anyone have a more cost effective method for removing this nut?

I don't know if it is possible to tell without getting the specs on the disks, but from what I have described, will I need to replace all the disks or just the ones with the 'pads' on them? Honda wants about $10+ a disk, is there a different alternative that is good quality and decently priced? Granted you get what you pay for, but are no name brands on eBay any good? Not sure about the boards rules on eBay links, but they are item #350320441571.

I appreciate any help you can provide!
 

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Please edit your signature to include your bike/s under "user control panel" so that we can better assist you in the future. Adding your location to your profile might also help in future parts searches or shipping quotes from fellow members that are trying to help you out..

Also, in your post you didn't specify what bike you're talking about. I'm assuming some type of CB/CM400/450, which I have no experience with anyway. Others here will though...


GB :mrgreen:
 

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You should replace all the friction plates, (these are the plates with the clutch fiber material on them) and replace all of the steel discs.
As for the springs, in your manual, there should be a spec for the spring height. You can measure them with a dial caliper (sears carries dial calipers, i picked one up for $25) if the spring height is shorter than the specs, you need to replace them as well. hope this helps
-Dan from South Jersey
 

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Discussion Starter · #4 ·
Heh...good point, I suppose that is some pertinent information. Profile is now updated, and this issue is regarding my '79 CM400T. :)

You should replace all the friction plates,...and replace all of the steel discs.
So all discs should be replaced regardless? What if (once I get that nut off) the steel discs are within specs, can only the friction plates be replaced? Or do both the friction and steel discs usually wear equally making the chances of that happening quite slim?

I checked the springs with my calipers and they range from 41.68mm to 41.50mm. The wear limit is 41.25mm so I figured that they would need to be replaced.
 

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mine is slipping too, I have all new barnett plates and honda springs (seams really tough to find a supplier for high performance clutch springs for a cb450k5) I just have not gotten around to installing it all.. mine seems to slip the worst shifting hard into second. be sure to check your basket for excess wear as well.
 

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Your springs are within the service limits (41.25 is the minimum length) but, not knowing what they started out at, I don't know how to tell how much life is left. Since they have been slipping there is the possibility of heat damage.

The minimum thickness on the friction discs is 2.30mm for the six inner discs (disc A) and 2.60mm for the outer disc (disc B). If they exceed these thicknesses AND don't show any signs of damage they should be OK to use.

Of course, since your clutch is slipping, assuming it is adjusted correctly, either the springs or friction discs must have a problem.

If the steel discs are smooth, show no signs of damage, and are perfectly flat (check this by laying them on a plate of glass) they should be OK.

Also check the "ears" on the discs for wear/damage.
 

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I have also heard that the type of oil you use can have a significant effect on a wet clutch.
Stick with oil made specifically for motocycles and it should eliminate oil related problems.

Kenolds
 

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A worn clutch is at it's worst in higher gears and is barely detectable in first or second gear- your problem sounds more like a linkage/cable/actuator and/or adjustment problem-unless it's also slipping in high gear. make sure you have those bases covered.
 

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Discussion Starter · #9 ·
A worn clutch is at it's worst in higher gears and is barely detectable in first or second gear- your problem sounds more like a linkage/cable/actuator and/or adjustment problem-unless it's also slipping in high gear. make sure you have those bases covered.
That is some of the best news I've heard yet, I think.... :) I don't want to discredit you or anything, but my luck usually isn't very good. Can anyone else confirm this?

Kenolds, I use oil suggested by Honda, can't think of what type it is right off hand. I doubt it is the problem, but I'll double check just in case.

In the mean time, I came across this post by HerrDeacon, viewtopic.php?f=17&t=1465&p=12789&hilit=clutch+tool#p12789 he used a brake caliper tool to remove the clutch nut. I think I will try the auto parts store tomorrow and see if I can find one. Then I'll be able to see what condition the discs are in.
 

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Discussion Starter · #10 ·
I appreciate everyone's patience. I picked up the caliper tool and modified it yesterday, it worked like a charm. I visually inspected and checked the friction discs and plates with a digital caliper. From the looks of it everything seems okay, in fact they seem to be in better condition than I was expecting. Below are the specs that I got:

Friction Disc B New= 3.0 mm Wear limit= 2.6 mm Actual= 2.97-2.99 mm
Friction Disc A New= 2.7 mm Wear limit= 2.3 mm Actual= 2.57-2.65 mm
Steel Discs- cannot find specs for them Actual= 1.97-2.01 mm
Clutch center-to-clutch plate B Wear Limit= 0.1-0.5 mm Actual 0.381-0.406mm
Spring free length New= 42.75 mm Wear Limit 41.25 mm Actual 41.68-41.50mm

I am guessing from this....that an adjustment at the cable would probably solve the problem right? I think I might do that and maybe get some new springs too. What do you guys think?

Thanks again!

Oh, and I'm using Honda GN4 10W-40 SJ oil. It states that it is okay to use with wet clutches so I don't think it is part of the problem.
 

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I think I would also replace the springs, looks like about 80% of "wear" used up.

While you have it apart you might also check the clutch actuating mechanism in the engine side cover to make sure it's working right. I haven't been into that part of mine yet so can't be of much help.

Looks like you've got a really good handle on this. :D
 

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Discussion Starter · #12 ·
Thanks for the suggestion J-T, I will take a look at the clutch mechanism, not sure what to look for but I will fidget around with it. :)

I don't think it is safe to say I have a good handle on it yet. Maybe once it is all back together and running we can say that, lol. I got a bit anxious since I was at a stand still with the clutch could not ride it. I've adjusted the valves, tightened the head bolts, pulled off the cables for lubrication, ripped apart the seat etc... if those springs don't get here soon I don't know what I will do to the bike next :shock:. So much for a quick balancer adjustment, lol. Oh well, now it will be ready for spring, hurray!
 

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Discussion Starter · #13 ·
The springs arrived today, hurray! However I have some more questions. I torqued the clutch nut to 34.5 lbs-ft, the range is anywhere from 33-36 lbs-ft. After torquing it, I decided to double check it so I loosened the nut and started to re-torque it, before it reached 34 lbs-ft one of the prongs on my tool broke. It is no longer usable and I am uncertain as to what the actual torque is now. I am going to guess it is 28-30 lbs-ft. Do you guys think this is okay, or should I go and get another tool?

Also, I cannot seem to find the torque specs anywhere in any manuals for the lifter plate bolts. Does anybody know what these specs are?

Thanks!
 

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grind one out of a cheap socket....
 

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current Honda tech manuals have a generic torque chart for all non specially specified bolts I believe it goes by head shape and bolt diameter. I was not able to find the info in my manual either, but if there is a 6 mm bolt on a bf225a outboard then its torque is about 9ft lbs. perhaps they think the spring tension will keep the bolts from backing out?
 
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