Topic: Dry Clutch Problems - why ??

[750goes]

If you want more photos of anything else to do with the clutch I can do them now - sitting in the study - making a mess according to the missus.....

[Jonesy]

BTW- I wonder how everything got so rusty in there?

dang..... beat me to that one.

I've seen a rusted clutch before in a friend's bike, but his was a different situation. He had a two-stroke dirt bike, with the transmission and clutch having their own oil supply (similar to a 4-stroke unit-contruction motor, except the crankcase was separated from the rest of the trans with seals). Water had gotten into the oil (looked more like thin, gray milk) and the clutch rusted together. We got it apart and after installing new plates, disks and replacement of the siezed clutch cable, he was back in business.

[mark]

I'll just add a quick thought here. Those small holes around the clutch inner also need to be open so that oil can get to the discs.

[Patrick]

This bike ran?

[750goes]

madmark73

- all holes are clear....I hope it is the oil pump....but I have a sneaking suspicion I have a blockage somewhere.....it may be that I finish up by pulling the motor out and check everything anyway.....then I get to check the head and rings....etc... it may be I need a valve job and hone at a minimum, plus new oil seals etc......and new camchain - may as well split the cases and do the primaries as well........

when I get the pump out will post up some photos of what I find.......from under the bike.....and from the clutch side...also post some photos of the sump remnants....

any ideas on why the oil would smell very fuel like

[750goes]

Pat,

the bike runs quite well - it has heaps of grunt, blows no smoke on startup or after running it for 15 minutes or so.....it need the carbs to be balanced - and #4 carb float adjusted - it pops out for low fuel after a few minutes idling...starts 2nd or 3rd try on electric start....does not have huge compression but when measured 18months ago (when I started this project) was around the 130 -150 per cylinder from dead cold (wet test)..it is easy to kick over though...yeah it runs...but obviously I need to do some more engine work on it......fine tuning I call it - 

[Patrick]

The grooves on the clutch center and clutch basket, from the pictures, appearsto be in good condition. Check for any nicks where the plates would have contacted them when the transmission was engaged. I would have expected the steel plates to be shinier, especially since there was no oil. Dry friction plates on steel sounds like a pretty good polisher to me. If there are spots on the faces of any of the steels it means they were stuck. Polish those up a bit.

I've never been able to properly revive used clutch plates that have been allowed to dry out. They get usable, but cruddy, when I've tried to revive them by soaking them in oil. I'd replace those if this was mine. The steels should be pretty shiny. I would have thought this was done, but I can't tell from the pics. Old eyes.

I don't think that's rust. I think it's dust from the dry clutch plates. I'm surprised it worked. Maybe that means the springs are still real good.

Patrick

[750goes]

Patrick,

I measured the springs (with a steel tape measure) and I wrote down 38-39mm...comparing that to the manual they seem to be really long......I will check them again tomorrow and post a few photos........

I have another clutch pack of plates and discs I bough some time ago....so I will have a look at those and compare (from memory the other plates were nice and shiny).....

anyone know the correct length or stacked height of a clutch with 7 clutch plates and 6 discs - one disc being a double

[Terry in Australia]

If you want more photos of anything else to do with the clutch I can do them now - sitting in the study - making a mess according to the missus.....

G'Day Charlie, well I've got a theory mate, but I'll need you to take a couple of pics close up, preferably with your missus balancing the clutch hub on her naked behind.............

But seriously, your oil smells like fuel because fuel is getting into your oil, most likely via the incorrect float level in carb #3 (?) allowing fuel to run into the cylinder and seep past your rings into your crankcase. I had the same problem with my K2, and actually filled the crankcase with fuel! (unlike you, I negated to turn mine off) If you need any bits, let me know. Cheers, Terry.

[750goes]

Terry, thanks mate-----the missus won't go for it....the picture I meant.....I can't fit the clutch hub in the frame on her skinny butt (tongue planted firmly in cheek)

I'll take a few photos of the exhaust header tomorrow and post it up - one cylinder is definitely getting oil from somewhere dripping or whatever on it, or it could be unburnt fuel ??

I don't see how if the culprit is a carbie that it must be excess fuel loading into it then being forced past the rings - particularly when the bike is running ??.... I'll take the plugs out also and sniff a bit...but there must be a wucking lot of it to dilute the oil methinks....

I am going to pull the pump tomorrow and try a few other oil galley lines as well..

the pump turns really easy by using one finger and pumps oil out of it...hope it is blocked somewhere that is easy to see and fix...

try using compressed air and see if I can spray oil everywhere...

If I need parts I'll go see Geoff - he's got a shed & garage full of clutches.....if he hasn't got any...I'll let you know....

thanks - had a long day - now time for the beer......

[eurban]

anyone know the correct length or stacked height of a clutch with 7 clutch plates and 6 discs - one disc being a double

Don't have the capability of measuring at the moment but total stacked height is taller on the later setups than on earlier.  I am fairly certain that the basket and the clutch center are taller as well. . . . One idea here.  Perhaps you could turn the motor over with the starter while the clutch / cover is out?  It might have to be cranked for a while.  If you are worried about the consistency of you current oil (if you don't have a blockage and you clutch area looks like it does in those pics then your oil must be closer to 87 octane than 10-40!) then drain and put in some inexpensive oil for now.  Oil should show itself through the proper passages (whichever those are) and make a mess if things are working.  No oil then clearly you have some lubrication issues.  Just an idea . .  .

[Jonesy]

The total stack of the later clutch is taller. According to Honda, if you wanted to run the "no rattle" plate in the earlier clutch assembly, you had to leave out one friction disc so as not to make the stack too thick. The later clutch had a deeper basket, clutch inner, changed lifter piece and modified cover. We used to have the tech bulletin on this website that detailed the changes, but the link no longer works.

[754]

Dont worry about the longer springs.. saves you buying a set.
They are likely aftermarket.. I would only run stock  clutch springs in a bike for Grandma..

And I did not see it mentioned.. make sure all the plates are flat..use window glass if you dont have a flat enough suface..and dont waste time with a feeler guage!! Just check both sides, it will pop up if warped and you press down on it..just try about 6 spots on each side..

[750goes]

thanks for the replies- am off to remove the pump - blow some air up some little holes, and might even remove the oil galley plugs and give them a quiet little workout as well.

I'm living in hope it is just a worn out and stuffed oil pump - or blockage in there...

[750goes]

Jonesy, also going down the route of undoing the transmission cover and see if I can remove that cover to see if it is clear as well.....

Anyone tell me where and how I can check all the oil flow lines/internals without having to strip the motor.....maybe take the oil galley plug/s off and blow air in there ?? I know there is one just above the clutch cover...any others that may assist ??

I know the oil tank & lines are clear, the oil pump seems to work - will let you all know a bit later with some more pictures..

Sump is removed and oil filter off.....now to go and get greasy again...

[Terry in Australia]

There are two more oil gallery plugs under the engine Charlie, but I doubt you'll get them out with the engine in the frame, and there should be a little rubber plug about 12mm in dia, on the left hand side behind the transmission cover.

Squirting compressed air thru 'em sounds like a good idea, but you'll need  a rubber donger of some description over your air gun's tip to get a good seal and maximise the effect. Clark Rubber should be open today mate.

Re: the fuel in the oil, the fuel isn't forced past the rings when the engine is running (unless your rings are stuffed) but seeps past them when the engine is off and fuel continues to run into a cylinder, normally iff you've got a knackered needle and seat. (float valve) Cheers, Terry.

[750goes]

Terry, thanks for that...that little rubber bung is a good thought as I may have discovered the error of my ways....see the following photos for the explanation..

I am yet to measure the oil pump for tolerances but think it will be ok......will let you know shortly......just arrived back home .......will cool down, have a cup of coffee and tell another story..........and I think breathing a little easier..........maybe even a smile...

[750goes]

well hear are the photos of the oil pump - not much to show here - will take a few more when measuring tolerances.......

[750goes]

I think problem is now solved.............................

Many months ago my transmission cover was leaking oil like the proverbial sieve.........so after starting a thread on this (I will go and find it and post the link)........the result was I purchased a bung from Clark Rubber (thanks Terry).........and proceeded to push it in the hole shown here with the screwdriver pointing to it...........and when I could not push it in further I cut it off flush......thereby - - plugging the main oil line (#$%* I'm dumb)....

I discovered this by using the compressor to force air back through the line from the oil "o" ring shown slightly to the right in the picture....I could not hear any air escaping but saw the bung bulging......took it out and voila - oil blew everywhere......I think I need to buy a proper oil bung from Honda instead of Clark Rubber........will continue with following photos......

[750goes]

here is the link for the original BUNG problem...

http://forums.sohc4.net/index.php?topic=13023.0

tolerances for oil pump - next.....

[Terry in Australia]

Ha ha, silly bugger! I've got a new Honda "Bung" in a box somewhere Charlie, if you can't get one sing out and I'll stick it in the mail for you. It's just a flat seal, not a cork, ha ha! Cheers, Terry.

[750goes]

Terry,

I feel as dumb as dog#$%*----and deservedly so...........I forgot when I put the little bugger in that this was an oil line that did not need to be plugged - I did not realise it went somewhere else...  particularly to the clutch......and main shaft.............glad I haven't registered it yet...or ridden it too far.....

I'll let you know if I can't get one from the local Honda people....cheers mate - have a good new year...mine is starting real soon.....

[CB750F2]

I am happy that you have found your problem. Do you think that the transmission has been receiving enough oil? The only oil that it would be receivong would be the return oil from the top end of the motor. Pat

[750goes]

Pat,

my whole thought has been - I've stuffed it up big time...but knowing how tough these buggers are I'm hoping there is no lasting damage............

Tolerances for the oil pump as follows:

Delivery Side outer rotor to body clearance - between .09 to .10mm, inner to outer rotor - about .15mm

Scavenge side outer rotor to body clearance - between .15 to less than .20mm, outer to inner rotor about .13mm

thankfully well within tolerance levels....

I now need to order the following bits to put back together
1 - oil filter screen (stuffed that up big time)
2 - oil filter & new oil filter bolt
3 - oil
4 - lots of bungs from Honda (hope they have them)
5 - transmission cover gasket
6 - clutch cover gasket
7 - 4 hours of good labour to put the bugger back together....

I also need to beg,borrow,bludge, or buy from a few local guys - another spiral cut clutch plate...clean up all my old ones -check for warpage - clean the whole clutch basket and assemble...the list goes on forever.....

 

[754]

Your top bearing, trans side looks bad, is that sludge on it or rusty?

Sounds like your trans bearings have run with less than usual oil, do want to assemble and try it for short time or for a long time??