Hello knowledgeable ones.
Just followed the basics to crab the frame and remove the clutch guts to see why I couldn’t disengage my clutch……
Inside the bellhousing it was heavily contaminated with gear oil. Oil on the friction material as well as a lot of gunge build-up on the internal teeth of the flywheel.
The rivet area of the clutch plates had elongated, but the pushrod, the intermediate plate, flywheel and pressure plate show zero hot spots, ridges or distortion.
I do intend to change all and every seal and the clutch complete as a matter of course. Interestingly the rear main seal was dry. The engine oil I’d noticed puddling below the bike seemed to be from a sump screw nearest the rear of the sump.
The gear oil contamination may be partly coming from the input shaft oil seal but mainly from the pushrod aperture.
I’m new to Guzzi clutches so am looking for any tips of best practice and parts suppliers.
If I could work out how to post some pictures I would but even my more technically able wife is struggling to assist😀
Worn gearbox input pinion. You’ll have to replace the clutch bits that bear on it as well.
The source of the oil leak is “not unknown”.
Good luck.
Thanks, but I’m not seeing any apparent wear on the teeth of the input pinion nor lateral movement of the shaft itself. No end float either and it turns smoothly in all gears.
Wouldn’t there be movement of the shaft or observable wear on the teeth if it was worn?
The bulk of the gear oil seems to be entering the bellhousing via the pushrod tube’s aperture which has left quite a bit of tarry residue over everything which i’m thinking/hoping may have caused the clutch drag and reluctance to disengage.
There’s actually zero appreciable wear on any of the teeth on the pinion, pressure plate or flywheel. Contact with the starter pinion is the only place there’s any small burrs.
There are seals on the pushrod, and there have been different types over the years. I can’t remember what is considered current best practice…
I would say if you’re doing the clutch, also do the gearbox seals, pushrod seals and the return spring. Most (all) clutch kits need the deep spline hub too.
A lot of debris in the flywheel splines is pretty normal I think. Where else is it going to go?
Originally the pushrod seals were like cone shaped bushes - at least 2 of them? Not sure how many now.
Thanks for the replies and good to hear you can get the pushrod seals and others. I haven’t yet cleaned everything up and am working the next three nights but will try to order parts.
Would this be the normal kit to replace?
RMS, gearbox input seal, however many pushrod seals, the clutch springs, X2 friction plates, X1 intermediate plate. (The pinion gear (on the end of the gearbox input shaft?)
I see there’s now a download button available which may show the only fault of the otherwise good friction plates (other than oil contamination)
Does this pinion part get changed out as a matter of course each time the clutch is renewed? Excuse the daft questions as this is my first Guzzi clutch job. If so, I suppose it simplifies cantering the plates on building it up.
……and if so, do I need to buy or make up a special tool to remove/replace it and to access the gearbox input seal, and possibly (if they live somewhere in there), some of the seals for the clutch pushrod?
It was so far easy to dismantle. No corrosion, broken studs or hidden horrors. I’ve been amazed how good it is for a 43 year old bike.
Can we have some more pix of that gearbox input pinion? It looks well worn. You don’t normally have to change it every time you replace the clutch but if there is any wear on it, the clutch will drag.
What is going on with the teeth at 3’o clock? Is that lumps out of them I can see? If so, there’s your problem…
As far as tools go, you’ll need a peg spanner or socket to get the nut off (there’s a locking tab underneath) it but easily fabbed up from an old socket…
PS dont throw it away…it makes a good clutch centering tool when it’s rebuild time…
I think it’s possibly a bit of detritus rather than chips but will head up there and see what other pictures I can do.
Is it normal for the rivet holes on the friction plates to elongate like that on these larger engined Guzzis?
Before I dismantled the bike I remember with the bike in 1st gear and engine off there was a little play in the driveline which I put down to general wear and tear of the driveline. The movement allowed by the rivet holes maybe explains it😃
It’s been a long time since I was up to my nads in one of these, but no, those elongated holes do NOT look normal to me. What would their function be?
TBH, it looks generally knackered.
But as I said, it’s been a long time…
Cleaned up all the bits and can see some wear on the gearbox input pinion and the intermediate clutch plate teeth. No sure how much is allowable but would rather replace them anyway.
Gutsibits seems to have everything except the intermediate plate and pinion. Is there any other U.K. outlet worth a try?Processing: D6B44271-594D-4299-90DE-BB7FB07A8960.jpeg…
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I think the clutch hub would not need replacing unless it’s worn, but most clutch kits have the later/deeper spline profile now, so you may need to get one anyway.
As mentioned, there is a peg socket to undo the nut holding the hub onto the gearbox shaft, and you can use one of your old plates to hold it still with a bit of adapting.
Are you going to do the shift return spring? Not too bad to do once the gearbox is out.
Ian
Return spring was not something I’d thought about. Sounds like it’s a to do job while box is out? Have to learn more about how to do this. Thank you for mentioning it.
I’m off on overnight shift work for the next four nights so may be a bit quiet until next week.
Gustibits don’t have any stock of their clutch kits although I have sent in an enquiry to find out when they could get it. There’s loads of other bits I’ll need to order too.
+1 to what the others have said. 
The clutch splined centre boss (from nomenclature in the factory manual) is showing wear, but I’ve had worse! When it goes too far, clutch drag is inevitable because the friction plates’ teeth don’t want to come out of the worn notches in the splined boss. If the bike is creeping forward in gear with engine running while stationary and clutch pulled in, it’s bad. Or, in gear and engine off, clutch disengaged, can’t push it backwards, but can forwards.
I agree elongated holes in the friction plates is not good, as said I think we’re looking at a complete replacement clutch pack and splined centre boss.
Yes nut for the centre boss needs special peg soclet, and can be a bear to come undone!
Gear pedal return spring – after decades of making these bikes, Moto Guzzi still couldn’t seem to get this spring strong enough not to break. Common occurrence. Usual advice is, if gearbox is out for any reason, and the spring hasn’t been replaced within living memory, replace it.
Cheers Mike, I’ve just ordered a workshop manual, and will have to check out the procedure for replacing the spring, torque settings as well as everything else
The works WiFi is considerably better than I get at home🤣
R.I.P., clutch centre boss. (I seem to remember that the term “gearbox input pinion” came from the Haynes manual, but I could be mistaken…)
It would also be instructional to have a look at the clutch pushrod and associated seals. I think that it would be prudent to replace it?