Clutch woes

The seca clutch has never worked right. When I had it first it was seized, when I ran it I managed to get it to free up, but it wasn't good.
So today I took it apart...
Things I found

 

gonna tell us the horror show you found ?

 

Sorry, my ipad just locks up on this site - I have no idea why...
Anyway, apart from the dirtiest inside of engine crankase ever, most of the plates were stuck together, there are deep ridges on the inner and outer basket fingers, the outer basket seems to have quite a bit of up and down movement.
In an ideal world I think I need a new basket and inner, maybe the steel plates will clean up, I allready have new friction plates ready to fit.
I've seen a clutch build how to somewhere, will have a look for it.

 

https://www.xjbikes.com/forums/threads/clutches-101-part-1-the-400-550-600s-with-pics.29541/

 

I'm sure you already know this , recommend replacing the springs and most of all the bolts , and clean the oil window while the cover is off cheers .

 

Thanks both, looking for bits right now. If the springs are all identical in height and not showing any rubbing wear I won't replace them. The bolts will be cheap - if I can get them.
Stti

 

Chacal Carrie's the bolts they are VERY easy to snap off when torquing them down ( don't ask me how I know ) .

 

Thanks, I'll always try to source locally, if I lived in the States @chacal would be my first choice...

 

An update on the clutch, now I've cleaned it for inspection - sorry if this upsets the purists...
Inner and outer rotors have deep galling marks.
The metal plates aren't warped or worn, but they have rust pitting.
The friction plates aren't worn.
Everything else is fine....
Aside from the clutch, the oil pump chain is slack, and has worn a pair of grooves in the tin guide. Is this unusual?

Now, I really would like to take this for a ride before stripping anything, so, given that the whole clutch basket will need replacing, the sump dropped to replace the chain, I've decided to put the basket back in as is for now. I will get a new pair of rotors and steel plates for when I take the engine out of the frame. So fingers crossed we'll have a clutch of sorts in the meantime.

 

Whilst cleaning the bits to refit tonight I came across a strange thing - the tiny needle bearings in the oil pump sprocket were worn flat! Now this did surprise me.
Anyway, I've decided to stop sharing the story of this, it seems no one is interested.
Thanks,
Huw

 

Well I'm interested! Just don't have any proper answers for you

 

I don't know the reason they are worn flat either, especially when the pump is in the sump.

 

The oil pump drive sprocket spins with the outer clutch basket, pull the clutch in and the gearbox input shaft it spins on stops. So the bearing only spins when you pull the clutch in. Strange it should flat spot the needles though, unless it''s done mega miles.
I'm struggling to find new steel plates, I can get xj900f ones - are they the same?

 

@chacal will know for certain.

 

Don't know, he's never answered any of my posts.

 

You could try checking the part numbers of the machines on this site https://www.cmsnl.com/ or fowlers https://www.fowlersparts.co.uk/browser/manufacturer/yamaha.

 

i don't think that's necessarily a bad thing they have little marks in them, you have more

 

As far as I can tell, the friction plates are the same, the steel plates aren't - maybe the inner "flutes" are different.
Anyway, clutch cleaned, the oil pump sprocket swapped.
I had to make a new cover gasket, topped up the oil, hung an aux fuel tank and away it went. Sounds sweet.Clutch is good, and for a bike that didn't run for 10 years it's pretty good - the v+h single pipe sounds sweet

 

That pic of the empty clutch case was to show the slack in the chain, but it doesn't really do it.

 

My oil pump chain is the same. Should be fine as there is not a lot of load on it. There is a thread on here about different thicknesses between the friction plates but the 900f has the thicker ones. If fitted in the 750 the clutch does not disengage fully. Not sure about if the 750 and 650 friction plates are interchangeable. Great your clutch is sorted.

 

My mistake it's the steel plates.

https://xjbikes.com/forums/threads/is-a-clutch-rebuild-necessary.129508/#post-653262

 

Thanks

 

Took this out for a tentative spin around the block today. Everything works as it should, low speed grunt is good, mid range feels a bit flat, all gears, clutch is good. Brought a smile to my face...

 

Oh, forgot to mention, spent a while cleaning and de-rusting the tank. Got hold of som phosphoric acid - instant shiny steel, although it wasn't bad, just red all over.
Also, rebuilt the petcock, but had a leak at the gasket /o ring with the tank. Now, I didn't take too much notice of the petcock mounting "nuts", but the ones in my tank weren't blind! They were open into the tank, so the leak was down the threads. The fix was to fit some o rings around both screws. Seems to have worked.

 

Like the looks of these bikes.

 

The jury is still out on the clutch thing - I just cleaned all the plates and refitted everything. So the worn inner and outer basket splines, pitted steel plates, and original friction plates are still in there, also the rubbish aftermarket cable, with at least 2 kinks in the outer sheath. So it still drags a little, but I'm putting this down to the cable, until I know differently.
All my experienced bike mechanics tell me the wear ridges on the basket splines can be filed out with no ill effect, but of course that's nigh on impossible with the xj. I have worked out a way to machine them clean, it involves a rotary table or maybe even my dividing head, as well as the slotting attachment, and will increase the backlash in the clutch - is this the end of the world? I won't know for a while.
Cable is on order though.

 

Grooves in the basket and boss must be very bad if you are thinking of a rotary table etc. Have a pic?
I've filed several clutch assemblies and found using a painted guide line is helpful...each one being filed down the same amount is key. Also important is that you file parallel to the fingers...in other words the long way, not across.

Some pics in post 103
https://www.xjbikes.com/forums/threads/1982-seca-xj650rj.128609/page-6

 

No, I wouldn't say bad, but the advice here says it must be smooth.
And its easier to machine than file, not to mention more accurate...
Edit to add - yours was like mine, difficult to make out though. And I re-iterate, very difficult to file accurately down to the base.

 

Down to the base? Never done that...I've always filed just enough to be smooth so the plates don't get hang up. The more material you remove...the worse it will get, no?

 

What I meant was that the basket, the outer rotor if you like, has slots that extend down into the case. You will have difficulty accurately filing lengthwise into these slots, but once set up on the miller, easy peasy.
Ultimately though, maybe it's neither here nor there, as long as the clutch works. Bigfitz writup says it will be notchy, with the plates "hanging up" - so far mine just doesn't quite release. I know I need a cable, so I shan't do anything until thats fitted.
If after fitting the cable it still doesn't release I shall machine the fingers, one thing at a time....

 

I must of misunderstood...I was referring to the fingers on the basket (outer) and boss (inner). (pics attached highlighted in red)

 

Yep that's what mine are like. I looked at filing them, no way, purgatory. And doing it accurately? Well yes, it's possible, but no thanks.
Hence using my machine is the best option. I'll post it up when I'm doing it, but don't hold your breath....