Topic: Wierd 400f clutch problem - solved (sort-of)

[many408]

See below the "=" for the original post...

Ok, here's what happened.

The original was all messed up.  The actuator arm was bent, the hole in the clutch cover that it bore in was worn out-of-round, the seal is bad, and the previous owner had installed the wrong clutch cable.  And glued the  gasket, stupid...

When I first started cleaning things up I replaced the threaded adjuster barrel that goes in to the top of the clutch cover - the P.O. had a different arrangement that was cobbled together from a smaller unit and a nut, both just sitting in the threaded hole, but loose.

When I put the cable outer in the proper adjuster barrel it sat for the first two or three level pulls and then the cable outer started extruding through the ferrule at the end - that's why I could tighten it up and it would work for a few lever pulls and then be loose again.  It's the wrong cable and the outside is too small, or the ferrule too weak, or both.

One of the other engines is now minus its clutch cover and actuating mechanism; that arm is not bent and it's a bit tighter in the hole, but still wobbly.  I will be bushing the first cover and then re-installing that with a new seal - will bush all the covers, actually, think that's a design flaw.  The top-hat-shaped actuator part that rides on the ramp gets loose as well when it has to deal with an actuator arm that wobbles - sloppy clutch action ensues.

That clutch cable is still there - I made a small c-shaped plate to fit around the inner, between the cable outer and the inside of the adjuster.  Then I found out that arranged that way, there wasn't enough cable inner extending past the end of the adjuster to go into the stirrup.  Out came the dremel, sliced off about an inch of outer, then split that length-wise so the individual coils could come off the cable inner.

So it works, but I don't trust it.  Getting a supply of new clutch cables, one goes in as soon as they arrive.

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Just fired up a 400f I bought last fall - and there's something funny about the clutch.

I set the adjustment correctly and made sure the cable was correctly seated at both ends, everything good, the locknut tight - after about 5 lever actuations the cable is loose and the clutch won't declutch anymore.  I can repeat the process of loosening the adjustment bolt, re-setting it, locknut tight, 5 or so pulls and it's no cable pull left at all.

When I have the adjusting bolt at the point that "...a slight resistance is felt..." it is almost all the way in - there are only three or four threads left for the locknut to grab.

I think the previous owner was in there and screwed something up.

Anyone got any good ideas?  Tomorrow I'm going in there but will check back here first...

[Bodi]

Strange. Is your clutch cable itself failing? Look at that first, you may need a new gasket if you pull the clutch cover so explore all external possiblities first.
The clutch is a "reversed" type with the springs pulling the back of the clutch outward to compress the disk stack. The release pushes in fron the centre of the cover to declutch, with a simple 3-ball climbing ramp assembly pushing via a throw-out bearing. Not much can go wrong there. I can't think of anything that would cause the clutch stack to get thicker, and the mechanism is not prone to the failure you describe. As the clutch wears you get tighter lever, not looser.

[many408]

Strange. Is your clutch cable itself failing? Look at that first, you may need a new gasket if you pull the clutch cover so explore all external possiblities first.
The clutch is a "reversed" type with the springs pulling the back of the clutch outward to compress the disk stack. The release pushes in fron the centre of the cover to declutch, with a simple 3-ball climbing ramp assembly pushing via a throw-out bearing. Not much can go wrong there. I can't think of anything that would cause the clutch stack to get thicker, and the mechanism is not prone to the failure you describe. As the clutch wears you get tighter lever, not looser.

I don't think it's wearing - not that fast (pull the lever 5 times and it doesn't work anymore).

I have a gasket set or two around - also a few extra engines, so if it's a broken thing then I can pull that part.

Was raining today so the get inside it got put off.

It seemed to me that whatever the clutch adjusting rod is supposed to push on is backing away when I squeeze the lever; each time I squeeze it moves further before the clutch (de)actuates.  There is a diagram in the Clymer manual, but that doesn't help much.  Last clutch I pulled was a 350f, and it was 30 years ago, so the details are a bit hazy...

[Bodi]

There are only two things I can think of. The cable itself is failing, ie one end fitting is slipping on the cable or the outer core is compressing somehow or the inner core is stretching somehow.
The other possibility is the clutch belcrank (#124) arm under the little cover. It may somehow be slipping relative to the actuator part (#137) inside the cover. Looking at the drawing you can se there isn't anything else that sems to be "slippable". The actuator ramp moves the entire assembly - including the bellcrank - in and out and the threaded rod (#129 that you adjust) pushes against #130, a centre piece fitting into the throwout bearing #261. The arm attaches to the inner plate #127 via flats on the outer end of the plate's shaft. Removing the adjuster lock nut lets you pull the lever off, make sure it's seated on the flats properly and neither the shaft or matching hole in the arm are damaged.

[many408]

There are only two things I can think of. The cable itself is failing, ie one end fitting is slipping on the cable or the outer core is compressing somehow or the inner core is stretching somehow.
The other possibility is the clutch belcrank (#124) arm under the little cover. It may somehow be slipping relative to the actuator part (#137) inside the cover. Looking at the drawing you can se there isn't anything else that sems to be "slippable". The actuator ramp moves the entire assembly - including the bellcrank - in and out and the threaded rod (#129 that you adjust) pushes against #130, a centre piece fitting into the throwout bearing #261. The arm attaches to the inner plate #127 via flats on the outer end of the plate's shaft. Removing the adjuster lock nut lets you pull the lever off, make sure it's seated on the flats properly and neither the shaft or matching hole in the arm are damaged.

That's a much better diagram - shows the actuator etcetera.

I have the cover off and the arm is seated correctly on the flats.  I think that there must be slippage between the inner side of the actuator and the ramps - the ramped part must be (supposed to be) fixed, and if it isn't then that would explain things.

Rain has stopped, update to follow...

[many408]

Update:

Clutch actuating lever seems to bent - the mounting surface (has hole with two flats) is not in the same plane as the cable attachment stirrup.  Will have to check on the other engines if this is supposed to be that way.

Hole in clutch cover is not round, and the actuating shaft wobbles.

Ramp also has a small amount of play.

I'll have  to bush the hole in the cover and replace the oil seal.  Meantime I will pull a cover from the other engine and put it back together and see what happens.