75 850 ES clutch

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Hi Lads,

I've done full searches on this forum & on the InterWeb about Commando clutches & have, I feel a good grasp of all the issues & solutions for dodgy clutches.

My clutch has a nice light feel so no issues with clutch pull (cable, cable routing, stack height etc.)

What is giving me trouble is clutch drag.

I've checked all the base settings as per owners/workshop manual (clutch adjustment bolt, actuating arm, cable free play etc.)

With the bike in 1st gear, rear brake applied, the rear wheel still moves when I kick her over!!

Obviously the plates are sticking.

When I drained the primary case oil I got 450cc's of oil out, should be 200cc. The bike does wetsump & empties the oil tank completely in about two weeks. I could have seal issues or when the bike was serviced too much oil was put in (I did not do the service myself, O' the shame :oops: )

Now for the question:

I'm being lazy :roll: and was thinking if I got some carb cleaner I could spray the clutch plates in situ to see if I can free them up due to being coated with too much oil? Is this a crazy suggestion? Should I just bite the bullet & take the cover off & strip the clutch, clean everything up, inspect a few parts & see what happens?

Could the carb cleaner cause any problems?

I know there could be other causes of the clutch plates sticking but I'm trying to do the easy stuff first!

So, cheeky carb cleaner fix with clutch in situ or just go ahead & strip everything (need to get a clutch tool!!)

Thanks in advance

Kevin
 
Hi,
I had similar problems, and believe it is the engine oil contaminating the plates. With my job, having to be away so much it does get left for periods of upto six weeks, it does not help.
Due to a worn kickstart shaft I have stripped the primary and had a good look at the plates and noticed that they are quite 'dirty' with a residue that looks like burnt oil on them - it looks like sticky black grease. Luckily being apart I will wash them and let them dry off. As for using carb cleaner, it may not harm the bronze plates but whether you can get it to fully penetrate between the plates is a bit hit or miss.
One thing I started doing was if the bike had wet sumped, as well as draining the oil from the crank cases I remove the level plug from the primary drive as well.
 
click said:
With the bike in 1st gear, rear brake applied, the rear wheel still moves when I kick her over!!
Click to expand...

Presumably you did mean with the clutch lever pulled in? If so then it sounds like a fairly serious case.


Clutch drag can often be caused by gearbox oil finding its way along the pushrod tunnel where it then escapes onto the clutch plates. An oil seal modification is available to prevent this happening.

One common cause of clutch drag is from a notched clutch centre which will stop the plates from separating properly.
75 850 ES clutch


If your MkIII clutch still has its original bronze plates, then it is usually a worthwhile job to remove and clean them periodically, as they tend to become coated in a film of black sludge, alternatively you could replace the bronze plates with Surflex plates? I've also heard that having the plain plates lightly sand blasted can also help to stop drag?

Some members here may recommend that you use ATF in the primary, which is fine to use in the majority of Commando primary drives, however because the MkIII models use a hydraulic primary chain tensioner that appears to rely on the type of primary oil in order to work properly, I suggest you try to keep to the factory recommendation of 20W/50 engine oil if possible? I have used ATF in my MkIII's primary case before, but the clutch didn't appear to work any better.
 
If your primary chain is too tight your wheel will move as well if you kick it over.
Put it on the stand and feel how easy or hard it is to spin the back wheel.
 
jaap said:
If your primary chain is too tight your wheel will move as well if you kick it over.
Put it on the stand and feel how easy or hard it is to spin the back wheel.
Click to expand...

I'm not sure that could affect a MkIII though?

As the MkIII's primary chain should be under nothing more than light spring pressure from the tensioner plungers when it's "at rest".
 
With the bike in 1st gear, rear brake applied, the rear wheel still moves when I kick her over!!
Click to expand...
hi there If you have the gear box in any gear while kicking over the rear wheel will turn.
 
L.A.B. said:
One common cause of clutch drag is from a notched clutch centre which will stop the plates from separating properly.
75 850 ES clutch
Click to expand...

That is without a doubt, THE WORST notching I've EVER seen on a clutch centre.
 
Hi Lads,

I really appreciate all your replies.

Just to confirm, yes I did have the clutch pulled in :D while in gear and kicking her over, the clutch pressure plate seems to 'lift' off the plates but the plates just seem to be 'stuck' together, the power of stiction!

Good suggestion about when draining the sump to also drain the primary chaincase, I'll add this to my pre-ride checklist :roll:

Level in gearbox is fine so I don't think the oil came from the gearbox + gearbox oil has a particular smell & the oil that came from the primary seemed to be just normal engine oil (I could be wrong about this but that's what I think at the moment)

As was mentioned it could be notching on the center hub but this bike was rebuilt by a chap who built 16 Norton Commando's & was very fastidious about everything he did, it was a hobby not a business so he just took his time & made sure everything was just right. As you do I've tinkered & stripped various bits off the bike, mainly for my education & each time I do this I'm impressed with all the little detail bits this chap did.

After saying all that I don't know for definite & the only way I will know is to strip the primary cover & clutch.

Is it advisable to change the chaincase gasket? any other 'bits' worth replacing while I'm in there?


All the best

Kevin
 
click said:
Good suggestion about when draining the sump to also drain the primary chaincase, I'll add this to my pre-ride checklist
Click to expand...

No need to check the chaincase each time.

To check the sump just keep an eye on the oil tank level.
 
Hi,

I've done some testing over time & can predict exactly how much oil drains from the tank into the sump each day. I used a steel ruler & checked the level every night for a few weeks.

What I have not done so far is check how much, if any, oil from the sump ends up in the primary chaincase. It would just take a few mins to drain the chaincase oil & check if there was more than I originally put in, this would then indicate if I had seal issues!

The last thing I want is oil building up in the primary chaincase causing more trouble with the clutch :?

Before I do any of this I need to free up my clutch!

I came across a comment in another thread that a lot of the issues we can have today with these classic bikes just did not seem to be around back in the day when these bikes where used as daily transport and that's the main problem. Rarely are these bikes used daily, I don't use mine daily, far from it, so I think you just have to come up with your list of pre-ride checklists which have specific checks due to the bike not being used on a regular basis!

Might start the stripdown this evening, I'll try & take some pics & post them here just in case it's of use to anybody else?

Kevin
 
It's much easier to simply pull the chaincase level plug.

If any oil dribbles out, it is excess that has infiltrated.

Just make sure to fill it properly, on the centerstand, till the level JUST reaches the level plug WITHOUT dribbling; that's what it's for, after all...
 
click said:
Level in gearbox is fine so I don't think the oil came from the gearbox + gearbox oil has a particular smell & the oil that came from the primary seemed to be just normal engine oil (I could be wrong about this but that's what I think at the moment)
Click to expand...

Any gearbox oil that does find its way through into the primary case will usually quite small, and it is unlikely to account for the substantial amount of extra oil you found in there, however if even a small amount of gearbox oil contamination gets onto the clutch plates it can be enough cause slip and drag problems.
If the extra oil in the primary wasn't the result of overfilling, and was because the engine oil had sat the sump for any length of time then it could have leaked past the oil seal, or it is also possible for the oil to travel along the primary case/alternator outrigger retaining studs (MkIII) if the threads were not sealed when fitted.




click said:
After saying all that I don't know for definite & the only way I will know is to strip the primary cover & clutch.
Click to expand...


Removing the bronze clutch plates so they can be cleaned of any black residue should really be thought of as an occasional service task and it doesn't take long to do, but don't attempt do to it unless you have the clutch spring compressor tool.

click said:
Is it advisable to change the chaincase gasket? any other 'bits' worth replacing while I'm in there?
Click to expand...

If the primary cover comes off without damaging the gasket then you can re-use it, although it's always a wise move to have a spare gasket handy, just in case it doesn't.
 
grandpaul said:
It's much easier to simply pull the chaincase level plug.

If any oil dribbles out, it is excess that has infiltrated.

Just make sure to fill it properly, on the centerstand, till the level JUST reaches the level plug WITHOUT dribbling; that's what it's for, after all...
Click to expand...


Hi grandpaul,

Good point, duly noted. On doing my basic checks I drained the oil from the chaincase & got 450cc's out. I put 200cc back in but did not keep filling until the oil came out of the oil level drain (have bike on center stand, level ground etc.)

I plan on stripping & cleaning the clutch but for future reference should I keep filling until it comes out of the oil level drain or just stick with the 200cc as per workshop manual?

Kevin
 
L.A.B. said:
click said:
Level in gearbox is fine so I don't think the oil came from the gearbox + gearbox oil has a particular smell & the oil that came from the primary seemed to be just normal engine oil (I could be wrong about this but that's what I think at the moment)
Click to expand...

Any gearbox oil that does find its way through into the primary case will usually quite small, and it is unlikely to account for the substantial amount of extra oil you found in there, however if even a small amount of gearbox oil contamination gets onto the clutch plates it can be enough cause slip and drag problems.
If the extra oil in the primary wasn't the result of overfilling, and was because the engine oil had sat the sump for any length of time then it could have leaked past the oil seal, or it is also possible for the oil to travel along the primary case/alternator outrigger retaining studs (MkIII) if the threads were not sealed when fitted.




click said:
After saying all that I don't know for definite & the only way I will know is to strip the primary cover & clutch.
Click to expand...


Removing the bronze clutch plates so they can be cleaned of any black residue should really be thought of as an occasional service task and it doesn't take long to do, but don't attempt to do it unless you have the clutch spring compressor tool.

click said:
Is it advisable to change the chaincase gasket? any other 'bits' worth replacing while I'm in there?
Click to expand...

If the primary cover comes off without damaging the gasket then you can re-use it, although it's always a wise move to have a spare gasket handy, just in case it doesn't.
Click to expand...

Hi L.A.B.,

I really appreciate your advice, very helpful.

Although I've had my Norton for about a year I'm only now starting to get to know her & ALL her perculiar ways & moods :lol: part of the 'fun' of ownership!

Have to get a clutch removal tool and while I'm at it I might get . . . . . . . . .


Kevin
 
I typically fill till it starts to dribble, then leave the drain pan in place for a couple of minutes before installing the level plug.
 
Hi Lads,

This is probably very old hat, but here are some pics of the start of the clutch strip. Everything looks in mint condition apart from the clutch plates sticking :)

I have to wait until I get the clutch tool to take the plates out & clean them, hopefully on Weds/Thurs.

More anon

Kevin

75 850 ES clutch


75 850 ES clutch
 
Just cleaned mine, as they looked dirty and what a surprise, the amount of crud that left in the bottom of the tray after they had been wire brushed in in white spirit was amazing - glad I done it now. The other place to clean out is in the clutch basket around the outside edge of the inner fixed plate in the corner, have a look it's most probably quite dirty in there as well. Having used ATF in the past and not having any at the moment, I have used some semi synthetic engine oil for Jap bikes that is suitable for wet clutches, the thing being if it does contaminate the plates it will most probably have little affect and be cleared via the scrolling and being semi synthetic may not be affected by the high temperature generated between the plates during engaging and dis-engaging, so far all seems fine.
 
Madnorton said:
Just cleaned mine, as they looked dirty and what a surprise, the amount of crud that left in the bottom of the tray after they had been wire brushed in in white spirit was amazing - glad I done it now. The other place to clean out is in the clutch basket around the outside edge of the inner fixed plate in the corner, have a look it's most probably quite dirty in there as well. Having used ATF in the past and not having any at the moment, I have used some semi synthetic engine oil for Jap bikes that is suitable for wet clutches, the thing being if it does contaminate the plates it will most probably have little affect and be cleared via the scrolling and being semi synthetic may not be affected by the high temperature generated between the plates during engaging and dis-engaging, so far all seems fine.
Click to expand...

Hi,

Thanks for the advice. Hopefully I'll also find a lot of 'gunk' on my plates & in the basket at least it would explain why I have a sticking clutch.

We have a classic bike event in Carlow this weekend & I nipped down yesterday. Two stall holders where over from the UK & had Brit tools BUT both said they had the Norton clutch tool in stock BUT left them at home as they thought nobody would want one!!!!!!!!!

I was going to make one but I don't have the correct size bolt! I'll just wait & get one over from the UK.

Once again thanks for the information above.

Kevin
 
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