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Depends on the sound. I wouldn't call a 'Grinding' sound normal. A high pitched 'Chinky-Chinky-Chinky' type ringing noise, (And yes it can be quite loud and obvious!) is normal. But 'Grinding'? Anyone near you with a Breva/Norge/Griso 1100 Sport (Not Scura,Tenni or Rosso.) you can compare it to?

Pete

Throwout bearing on Guzzis is a small 'Torrington' type needle roller at the back of the gearbox. If it fails it usually does so silently and suddenly but you'll get a short period where you have to pump the clutch to get it to engage as the space taken up by the rollers has to be filled by pushing the thrust piece forward.

it is VERY, VERY unlikely that it has failed, not impossible but unlikely. Put your mind at ease and take it to Larry and give him my regards will you. I met him in 200(?)4 when I was touring around on my Convert.

Pete

The normal rattle is the result of the splines on the insides of the friction plates and ostly the splines on the outside of the intermediate plate rattling on the splines of the input boss on the gearbox and the splines in the flywheel itself.

Concentrating on the flywheel this is a bit of cast steel, tap it when you're holding one and it will ring like a bell (Unless it's cracked!). When it is on the bike and the engine is running the firing intervals of a 90* V-Twin with a shared crank pin for the connecting rods are 270 and 450 degrees apart, (#60* -90* and 360* +90*) are uneven. It is this uneven-ness that gives the engine its characteristic 'loping' sound but it does mean that the crank tends to accellerate and decellerate unevenly and at idle, especially if the idle is low, (A Griso should idle at 1200RPM-ish.). When this happens, when the clutch is engaged the intermediate plate is 'loose' between the two friction plates and as the crank speeds up and slows down it whacks back and forth in the flywheel splines acting like a clapper for the flywheel's bell and you get the 'Ringing' 'Chinky-Chinky-Chinky' noise I described above. Also the friction plates, which are also 'loose' when the clutch is engaged may still have enough drag on them to rock on the input boss but this is usually silent. Any knock at idle when the clutch is disengaged is usually down to poor throttle body ballance or a too low idle causing the same 'Backlash' problem between dogs in the gearbox itself and between the primary gears.

I still don't think that it is very likely you have a problem but better safe than sorry.



Your clutch assy. Intermediate plate is part #4

Thrust bearing is part #9

Pete

The Griso clutch makes hell and all racket. It's enough to even frighten modern Ducati riders. I can't imagine you have a problem there.

Last year I had to have the whole assembly, parts 6 to 14 renewed on warranty, as they all nearly fused together. This was caused by throw bearing siezed and pushrod assembly whizzing around causing great friction.
The sound my Griso 8v made just before the work was done, was grinding / sqealing, and not the normal robust clutch spinning noise.
This subject was covered in depth a few months ago, see this link,
http://forum.guzzitech.com/forum/163/2559.html
Other than that, its the best bike I've owned, soon to get better when I get my shit together, and fit my full PCV/AT/etc.etc.

8V uses a completely different clutch assembley.



If your thrust bearing died it is most likely because the wrong pushrod

Part#12

was fitted. With the new single plater there are four pushrod lengths, on assumes to allow for variations in plate thickness and manufacturing tollerance. They come in 183, 184,5, 186 and 187.5mm lengths and it is important to match 'em up. if a too long rod is used the thrust bearing will remain constantly pre-loaded meaning that a.) the clutch plate won't recieve the full clamping force of the spring and b.) the thrust bearing will be spinning, under load, at crank speed the whole time which it is not designed to do. On earlier twin plate bikes if the cable wasn't adjusted so the bearing was under load the pushrod had a tendency to spin in the thrust cup and eventually it would friction weld itself in there and everything would go to hell in a handbasket real quick!!!!

I think that a few of the early bikes suffered these sorts of problems because the assembley line workers weren't told well enough why they should be doing stuff. Remember, assembley line workers AREN'T mechanics so they may not understand why they have to do stuff. Mind you, there are plenty of mechanics who miss stuff like that too.....

Pete