Topic: CB500 Clutch Issue

[Mo]

Hey All,

So on my 72 CB500, then clutch is acting up. When its cold, just starting to ride, the response is good and exactly as I expect it to be. As the bike continues to warm up, it feels as though the adjustment is coming loose, and then bike will creep forward with the clutch pulled in.

I've been over the adjustment several times, and all of the locking nuts are locked. What am I missing?

[brooze72]

Well a simple idea is oil, how long since the last change?  These beasts are sensitive to using the correct ( wet clutch compatible) and fresh oil.  If that doesn't help, check the push rod ( can crack or get flat ends),  2nd idea is the cable is stretching.  I have a similar issue that came up at the end of last season, maybe not as bad as yours as mine just gets grabby when hot, so I will be checking the clutch plates & changing the cable & oil this spring ( if it ever comes).

[Mo]

I've recently rebuilt the clutch (deglazed and soaked in oil for 24 hours) using Rotella T. The cable is also a new oem cable.

[rb550four]

Has anyone checked or changed the clutch springs . They are 35 years old , and may not be as rigid as they used to be . Do you think that it is possible that the oil temp is effecting the spring tention when the temp goes up?

[wjustinleigh]

What kind of oil is in the bike?  I was having a number of clutch issues, most recently setting the tension screws to the proper torque with my new torque wrench purchased specifically for that job and ordering the right oil fixed my problem.

Even with the clutch in the bike wants to go forward as the clutch plates are close to the friction plates which are still spinning, all my CBs have had a slight forward motion with the clutch in and in first.

[dave500]

adjust the clutch when its fully hot so it wont drag,you might find when its cold itll lurch or stall when you select 1st for the first time?how was the baskets end float?how worn is the cork screw mechanism?

[Mo]

Hey Dave. When I took it apart, everything was well within clearances (the metal plates, springs, and the cork/friction material looked fine). On the other side, the lifted actuator thing (is this the cork screw you are referring to?)was pulled apart, cleaned and lubed.

The clutch really is fine when its in adjustment. It just happens to lose that adjustment ~10 min into riding.

[Deltarider]

Also verify the sprocket cover is tightened well (4 bolts).

[dave500]

the ball isn't missing in the cork screw and the rod is in one piece?you might need to check the basket end float again?

[iron_worker]

Check that the "cork screw" actuator pieces isn't cracked and also the push rod as Dave said.

IW

[dave500]

the female piece in the case is alloy and can wear out letting the steel male piece crank a little sideways which will lessen the disengagement throw somewhat,its still available if yours is very worn or cracked,if its broken where the dust cap if its present fits on itll be worn too much most likely?

[Mo]

All, thanks for the reply. Ball is there, and the corkscrew is indeed in one piece when a checked it last. I will remove the side cover again and verify that all is well,  although as of 3 weeks ago all was well.

At the end of the cable that goes into the side case, there are 3 nuts. One 10mm which adjust the free play. A 12 mm which I assume just locks it, and a 14 mm, which I have no idea what it does. Does this sound right? Like in the pic below.

(http://www.ebay.com/itm/New-Clutch-Control-Cable-1971-1973-CB500-Four-K0-K2-Genuine-Honda-OEM-I11-/271445112315?pt=Motorcycles_Parts_Accessories&fits=Make%3AHonda%7CModel%3ACB500&hash=item3f3363b5fb&vxp=mtr)

[Mo]

Okay so I took a look at the manual, and this might be a dumb fix. For the adjustment at the case end, is the lock nut supposed to be flush with the adjuster (the 10mm bolt) or the case side (14? mm nut)? I currently have it towards the case, but can't be too sure (although this does make the most sense).

[Seeker0131]

  These bikes are notorious for this issue.  Your not doing anything wrong at all.  In my belief this is the Achilles Heal of the entire design of the bike.  I had the same issue for quite sometime, and couldn't figure out if it was something missed or was I not following the procedure correctly (it was neither).
  My clutch is adjusted in such a way that jerk's a little when cold, but smooths out when running for extended periods
 
  The way that I adjust my clutch so it is on the tighter side of the "feel" spectrum.  Depending on the type of clutch springs you are using (I am using red springs for racing applications) will determine the type of feel you experience.
 
 The procedure that I follow is as such, and it is with a cold motor (keep in mind that I am doing this off the top of my head, and don't have the manual in front of me):

~Assuming all parts are clean and lightly lubricated, and there is full slack to the cable in both directions (at the perch, and at the case) I start by loosening the 10mm hold down bolt for the slack adjuster (worm/screw gear).

~Using a high quality tool for the large slotted adjuster, (a Quarter) turn the adjuster full clockwise until it stops (don't force it any further), and then I move it the opposite direction just off of that stopping point.  This should be right around the hash mark that is cast into the cover.  Rule of thumb is to set the slot in line with the mark.

~I then tighten the 10mm set bolt in place, and take up the cable slack with cable adjuster at the case, feeling and watching the lever at the perch as I do this.  When I begin to get the feeling of the clutch springs that I like (without any binding) is when I take up the remaining slack at the case,  leave room for fine adjustment at the perch adjuster, and lock down the double nut

~This is where I take my free-play adjustment specification in to consideration, and determine whether or not I have to make some other adjustment's to what my preference is.  When satisfied, I lock everything down and double check that I have everything in order. 

~I do a good test ride to see how my adjustments are. If I don't like it, I do it again, until I do like it.

  NOTE: Lever excessively tight will put undue stress on the cable, and will wear it out quicker (possibly even snap at an inopportune moment, in which you will either have to call for a tow or time traffic lights exactly...I've had to do the later more then once).  I have noticed that my bike hates stoplight's, and rush hour traffic.

Take It Easy

[Mo]

Okay so I gave it a go. The mechanisms under the cover are all A okay! I then took a shot at re-adjusting. Initially had it too tight, and wouldnt smoothly shift out of 1st. Re-adjusted and was working OKAY. It tends to grab right at the end of the lever play, but I know that is normal for these bikes. It's raining and cold, so I didn't have too much time with it. Took it around the block once, maybe 2-3 min of riding, but it seemed okay.

In terms of the adjuster/locknut, this is what I got. The 10 mm (top) seems to be locked in the same rotation with the 12 mm (middle). However, all three move with the 14-15mm (bottom). It's hard to tell if the 10mm is loose (I don't think it is). Thoughts?

[wjustinleigh]

Mine is not screwed out that far, that seems like the cable is barely in the nut that slips into the case which means the cable is only working with the top of the throw of the corkscrew/actuator piece.  I'd back the smaller nut off, then screw the cable into the nut that is inserted into the case and re-tighten the smaller lock nut.  In my case, it's almost all the way in.  Then read adjust the cable mechanism at the lever so it's in the middle of the adjustment range then adjust the clutch adjuster so the lever moves freely for about 1/4 inch then begins to disengage the clutch.  Not sure if any of that helps but I'll post pics of my set-up later tonight.

[Mo]

Hmm this setting works well when cold. Not sure how it'll work when warm. I do indeed have more avail travel.

[Mo]

The problem went away for a day or two, but it is back now. Any others got any ideas?

[wjustinleigh]

I can't think of a reason why it would work for a few days other than if the adjustment holder is slipping.  If changing the cable gave you more throw and it is slipping slowly it might take longer to loosen to the point where it doesn't have enough movement to fully disengage the clutch?  There's a piece that the adjuster bolt screws into which holds the adjuster in place, looks like a crescent moon.  Was it in good condition?  I think I have an extra one laying around if you think it'd help.

You said that cold it works, then you lose the ability to disengage the gears when it's hot.  When it returns to cold again does it work again then or do you have to re-adjust to make it disengage?

It's full of quality oil right?  When you took apart the clutch basket did all the plates move independently?  I could see if the steel plates are getting hot and expanding that would increase friction making it difficult to disengage when the engine got hot, especially if the clutch rod had diminished throw.

[wjustinleigh]

Here's a pic of the part I was talking about that holds the adjustment in place.

[Mo]

So, when it gets hot and loses it, it needs to be re-adjusted. I'm going to back and check to see if the spiral holder locker thing is worn or not. That might be it? Will report back.

[dmai]

I too, have this annoying issue. Read through this entire thread and didn't see any mention of oil type/grade used. Anyone WITHOUT clutch issue... what oil are you using? Wonder if this could be the fix?