CLUTCH BASKET TOUCHING PRIMARY

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willy mac

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Not a new topic I know,

I have a belt drive primary and the clutch basket has started making contact with the primary case when I kick it over, the wobble in the basket is nothing new from reading in the forum, but just wondering if anyone has had this themselves and what you did to remedy it.
I don't think it's making contact when running as there is no noise I can hear and nothing to feel, there are no witness marks on the case but the edge of the basket is showing signs of contact.
Clutch works fine and gear change is sweet, at the last put together the clutch centre nut was torqued to 35-40 lbs ft .

Any thoughts would be appreciated.

Mac.
 
Hi, if it was working fine just before, may be the mainshaft circlip locating the clutch spacer had failed and thus had migrated a bit in wards, otherwise maybe missing some spacer the 0.048" or 0.036 " one (s), ouwarfds the spacer, we hope your mainshaft is straight...........more to come, hope this help!
 
If , it just rub when kicking ........did you take out the primary outer case to ahve a look when kicking ? if the fact of pushing on the kick could make the mainshaft going inwards , there could be some trouble with any bushes in the tranny..............more to come!!
 
Has the clutch been assembled incorrectly, the clutch center nut come loose or the inner case centre stud missing its spacers??

Dave
 
You are saying it "started" doing this? Check the mainshaft nut on the right side. If loose it allows the mainshaft with clutch basket to move outwards. Happened to me when mine was brand new and I used a roadside rock to tighten it in the middle of nowhere. There is a tool for this to avoid hurting the nut.

Russ
 
I've taken the clutch apart today and removed the basket. The nut was still tight, circlip still in one piece, the recessed washer and spacer were correctly fitted, hardly any movement in the mainshaft in any direction, same again with the clutch centre on the splines, but there seems to be a fair bit of slop in the basket bearing.
The only number I can see on the bearing is FSS166 6007, any of you who are good with bearing types and quality might be able to say whether this is a decent or cheap and nasty bearing, my thoughts are with the latter. I think a new one might be the first move from here.
 
Hi willy mac,
I would have thought the clutch plates and diaphragm would push a loose basket back away from the outer case. Is the basket catching all the time or only when you pull the clutch lever? Is there any in out movement of the primary casing, can you pull it out away from the clutch? And finally, what was the last thing you did?

Dave
 
Hi Dave

The only time the basket is catching as far as I can fathom is when it gets kicked over and it's catching the outer casing but not leaving witness marks. Clutch operation is fine as is gearchange. The last thing I did was put the primary back on the gearbox had not been touched. More investigation required me thinks.
 
Hi Willie Mac, did you get to the bottom of why your box was jumping into gear when switching off because you say the box is working fine now which is a result .?

Jg
 
auldblue said:
Hi Willie Mac, did you get to the bottom of why your box was jumping into gear when switching off because you say the box is working fine now which is a result .?

Jg
Click to expand...

Hi there, I never got to the bottom of what was causing it to jump into gear, it's not done it for ages, so it's working fine apart from this primary issue.
I'm trying to find a figure for mainshaft end float and failing miserably, the Commando workshop manual doesn't seem to mention it nor does Old Brits in their online gearbox build sheets.
The basket touching on the outer primary case prompted me to do a bit more digging, I'm showing 1.5mm of end float on the mainshaft measured at the clutch end, someone mentioned earlier that the nut on the mainshaft on the kickstart side had come loose and the whole thing had moved across, That would explain the clutch basket hitting the outer case I've not ripped into it yet but that might be the next step providing I can get an end float value.
To answer some of the other questions the mainshaft looks straight but I think the splines might be a bit worn as the clutch centre has a slight rock to it, when this is measured at the edge of the clutch basket I can see 0.75mm, this rock on the shaft and the end float might be the answer to the contact with the outer chain case.
I only have 1 shim on the mainshaft on top of the clutch location spacer so that could come off too to give more room.
I've not tried putting pictures onto the Facebook page yet but I'll give it a bash in order for you to see what I'm on about as I never seem to be able to load them on here.
 
willy mac said:
I'm trying to find a figure for mainshaft end float and failing miserably, the Commando workshop manual doesn't seem to mention it nor does Old Brits in their online gearbox build sheets.
Click to expand...
If a ball bearing has more than .010/.015" lateral movement than it is DEAD. Probably not your problem. :!: LOOSE nut?
If the clutch is hitting the outer primary than you should pull the whole thing/ gearbox and primary/clutch apart, the problem should slap you in the face...unless you are comatose. Great learning experience. :mrgreen:

Shop manuals are written NOT as beginners guides, but for seasoned/trained mechanics to get them past the pit falls and TO the specifics that matter. What is an Old Brits "build sheet" ?
Your
clutch center bearing 62x35mm should have VERY little movement in/out. It is more critical on a belt drive, less so on a chain drive.
 
Dare I say it, is the spacer fitted to the top gearbox mounting bolt on the correct side?
 
willy mac said:
I'm trying to find a figure for mainshaft end float and failing miserably, the Commando workshop manual doesn't seem to mention it nor does Old Brits in their online gearbox build sheets.
Click to expand...

If the nut at the RH/timing side end of the mainshaft is tight, there shouldn't be any end float.
 
gripper said:
Dare I say it, is the spacer fitted to the top gearbox mounting bolt on the correct side?
Click to expand...

I would not normally think you could get the washer in on the right side, though the ingenuity of some folks is sometime limitless.
If the 9/16 washer is left out you warp the engine cradle and can pull the primary case toward the swing arm (&clutch).

Primary hitting the swing arm is actually is one of the problems on a club members 73-850 that has been to 3(not norton) Professional ($$) restoration shops. For a $16k restoration, Not one of them got it right. 5/8 x .125" hardware store washer? I've been trying to find the correct part, some use the 9/16 rear wheel axle washer which is actually a bit to thick.
NHT engines and pre commando gearboxes are 3.31/3.33" wide and the commando gearbox is approximately 3.18"/leaving around .140" to .170" washer.part 03-0023 Additional primary shimming is needed.,
 
"I would not normally think you could get the washer in on the right side, though the ingenuity of some folks is sometime limitless."

Embarrassingly, I was that ingenious person. Not for long though :oops:
 
batrider said:
You are saying it "started" doing this? Check the mainshaft nut on the right side. If loose it allows the mainshaft with clutch basket to move outwards. Happened to me when mine was brand new and I used a roadside rock to tighten it in the middle of nowhere. There is a tool for this to avoid hurting the nut.

Russ
Click to expand...
Hi Russ

Checked the mainshaft nut on the kickstart side today and it's tight( well I checked it at 40lbs/ft) as there was some discussion about the 70lbs /ft mentioned in the manual being too much and 35-40 was deemed a more acceptable value.
So until I can find a definitive value for end float I'm still head scratching.
 
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