2006 GRiSO 1100 transmission problem

I recently purchased a 2006 Moto Guzzi GRiSO 1100 in the UK. 12,500 miles on the clock. Great looking bike and great to drive. However, on closer inspection there is a problem with the transmission and drive. There is too much ‘noise’ (rumble) coming from the Drive shaft area and possibly the gearbox. When stationary and the clutch is in, there is the usual dry clutch noise. When the clutch is let out, there is too much rumbling noise coming from the transmission and gearbox area. I have been advised that this is a definite problem and would require the Drive shaft to be disassembled and inspected for full diagnosis. Potentially it could be the UV joints on the each end, and worst-case-scenario, the CARC transmission.
Looking at the previous service I also noticed that AGIP 1740 85W140 transmission oil has been used, as opposed to the recommended 80/90 oil.
The questions I have are: -
a) Is the 85W140 oil likely to have caused this problem? (it has run 1000 miles on this)
b) Is this a problem anyone else has experienced? and if so, how did you deal with it?
c) Any other helpful comments would be welcome..
Many, many thanks in anticipation.

Give me a couple of hours and I'll give you a run down on the likely cause of the problem.

Righty-ho. Let's look into the depths of my scrying bowl and see if we can identify the problem with this beast.

First of all a bit of history. Early 1100's, both Breva and GRiSO, had two significant 'Known' issues that were recognised by the factory. I'll come to those in a minute but generally both the gearbox and the bevelbox are pretty damn bulletproof so don't act in haste.

Issue number one was the use of an inferior bearing in the bevelbox. This is the large crownwheel support bearing just behind the big seal visible when you take the wheel off. The bearing used had only 17 balls and a very poorly riveted cage and would break up its cage, usually early in the piece, and push great chunks of it through the oil seal allowing a flood of gear oil out all over the rear wheel and brake. For some reason this was deemed to be a safety issue and a recall was instituted of all affected machines. A list, which I unfortunately no longer have access to, was published with the serial number of affected CARC bevelboxes listed. This number is stamped into the flat area under the flap of the top rubber boot on the bevelbox and even now it should be possible to go to your 'Authorised Guzzi Dealer' and have them check if the machine was subject to the recall and whether it was completed.

Although a safety recall there is, in most jurisdictions, a ten year moratorium on such issues which in the case of a 2006 machine has obviously passed but finding out if it was eligible and/or if it was carried out will enable you to know whether you need to replace that bearing. While I do not think this is related to your noise issue it is something that is important to find out. When the bearing fails it usually does so silently but accompanied by a flood of oil so it's important to replace the bearing before that happens. It's not a huge or hugely expensive job. I've done a photo essay on it which I believe is in the tech section somewhere.

The second issue which I think might be a more likely culprit is that of the driveline shock absorber on the gearbox input shaft. Since time immemorial Guzzi had used a face-cam shock absorber on the input shaft that consists of two ramped cams that when loaded up by driveline forces ride up one another against the force of a substantial spring. When the load is released the spring pushes the cams back down into their respective valleys releasing the energy stored in the spring. It's a very simple system used since the dawn of the industrial revolution and in most cases works well.

Originally Guzzi used a coil spring but some time in the mid nineties they cahanged to a stack of Bellville washers instead. Now that in and of itself wasn't a bad idea as the coil springs were known to shatter occasionally with somewhat ugly results but despite it having worked flawlessly for ten years with the early Breva and GRiSO they managed to fuck it up!

What exactly causes the problem I neither know nor care. It was probably a tempering issue with the washers. But the result is that for some reason the washer tower tends to collapse to the point that when the shock absorber is 'At rest' there is insufficient pressure on the cams and they can rattle against one another. This can cause a knocking, rumbling sound at idle and in some more extreme cases cause a snatch take up of the clutch when pulling away from a stop accompanied by some knocking and banging!

Now Guzzi, ever keen to avoid paying anyone for their screw ups, claimed that all this ungodly racket caused no harm and not to worry about it, (A theory that I, having seen a fair few gearboxes with busted springs that have expelled their spring retainer collets and the resulting carnage I can't agree with!) but if people insisted they would provide some shims to add more preload to the washer stack which was supposed to cure the problem, (Although this has proven a bit hit and miss. I did this fix for a member here a year or two ago and although it improved the situation it didn't cure it.) and this of course requires removal and disassembly of the gearbox.

That issue apart the 'Nuovo Six Speed' used on both the 1100 and 1200, (Be aware though that although outwardly identical the two are quite different and one can't be substituted for the other.) are effectively bulletproof. I've never has one apart because of mechanical failure.

Now there are a few more things I need to say about this bike and issue but right now I've got to go and do some actual work! I'll return to this in a couple of hours.

marshyguzzi2 wrote:

I recently purchased a 2006  Moto Guzzi GRiSO 1100 in the UK. 12,500 miles on the clock.  Great looking bike and great to drive.  However, on closer inspection there is a problem with the transmission and drive.   There is too much ‘noise’ (rumble) coming from the Drive shaft area and possibly the gearbox.  When stationary and the clutch is in, there is the usual dry clutch noise.  When the clutch is let out, there is too much rumbling noise coming from the transmission and gearbox area.  I have been advised that this is a definite problem and would require the Drive shaft to be disassembled and inspected for full diagnosis.   Potentially it could be the UV joints on the each end, and worst-case-scenario, the CARC transmission.
Looking at the previous service I also noticed that AGIP 1740 85W140 transmission oil has been used, as opposed to the recommended 80/90 oil.
The questions I have are: -
a) Is the 85W140 oil likely to have caused this problem? (it has run 1000 miles on this)
b) Is this a problem anyone else has experienced? and if so, how did you deal with it?
c) Any other helpful comments would be welcome..
Many, many thanks in anticipation.

OK, now let's look at some specific issues.

1.) The fact it's got 85/140 in it rather than a 75/90, 80/90 or straight 90 wt? In reality this is unlikely to cause any issues. I'd advise against it due to the fact that the lubrication system for the pinion nose bearing relies on a fairly small and poorly supplied internal gallery in the pinion. In cold weather an 85/140 won't flow as fast, even though it's spec says it will, and might cause inadequate lubrication and cooling of the rollers. It might not either, but because replacing it is an expensive pain in the arse I'd stick with a 75/90 to err on the side of caution.

2.) I have to ask? When it's making this horrible noise you haven't got the bike on some sort of stand with the back wheel off the ground and then find if you let the clutch out when the bike is in gear it makes a horrible clattering noise? If that is the case? Just stop it! The uneven power pulses of the 270/450 firing intervals will cause all sorts of horrible driveline harmonics. Put simply it's not designed to be run in gear without load, especially at low RPM's

3.) Who last tuned it? Do they understand the W5AM ECU and how it works on Guzzis? Do they have the diagnostic tooling to perform a proper tune up? A good check of these things is to check the air bleed screws. If they are both open then the bike has been tuned by a shaved ape who doesn't know what he's doing. Furthermore if the paint is missing from the throttle stop screws on the throttlebodies or linkage rod ball joints you have just entered a world of pain and any noises from the driveline may simply be down to the engine running like shit and causing massive backlash issues between the teeth of the primary and secondary pinions in the gearbox.

4.) While not impossible it is highly unlikely that the driveshaft trunnions will be giving problems at such a low mileage. Although if it has sat unused for long periods of time there is a possibility the grease has dried out and the needles deteriorated. The good news is that the driveshafts are easily rebuildable and the Hookes couplings inexpensive. The simple way to find out would be to inspect the shaft which will be made easy because.....

5.) None of the CARC bikes ever seem to leave the factory with adequate grease in either the swingarm bearings or shock linkage bearings. By now, 14 years on, I'd be very surprised if yours aren't just a mass of rust. If you are really lucky and the bike was only ridden on sunny afternoons by its previous owner(s) you might get away with just greasing them, but I wouldn't hold my breath. If the linkage bearings are shot it's no more expensive to just buy a complete new linkage than it is to buy all the bearings, bushes and seals you'll need for the old one. Just make sure you grease it really well before you install it. The wishbone you can just replace be bearings and seals. The swingarm bearings are a 'Factory only' part as far as I can make out. Not because the bearing is rare, on the contrary it's a 'Free Grandfather Clock with Every Half Dozen' 32205 I think BUT it's an RS bearing and the seal type is unlike anything I've been able to find in the aftermarket. Good news is they aren't that expensive.

To get to them you need to drop off the footrest hanger plates and swingarm. That make this the ideal time to check the drive shaft trunnions. My guess though is that they will probably be fine.

Pete Roper, That's great, many thanks.
I'll have a good read and digest.

marshyguzzi2, if you want to check that your 1100 was affected by the CARC recall, I kept that information from when mine was done.

'GRiSO 1100's up to VIN ZGULS...6M111954 will have CARC rear drive units replaced due to the bearing fault'

'All CARC units up to number 003171 will be replaced.
The rear drive unit number is under the rubber boot.'

Brian

Thanks Brian!

Many thanks Brian

Brian and Pete Roper,

the CARC serial numbers are:-

642377
02968 R

I believe this does mean that it should have been recalled (under 3171).  Given the 'R' suffix, does this mean 'Recall' do you think?

Many thanks!

I'm not sure if the 'R' means that the CARC was replaced or not, I think you will have to check with the Dealer or Moto Guzzi.  My CARC, before it was replaced, had 642377 02504 stamped on it.  The new one only has 009088 stamped on it.

If you can lift the rear wheel off the ground you should be able to check for any play in the bearing.

Also it's part of the MOT to check wheel bearings, it would have failed if there was excessive play. If there was a small amount of play it might have been mentioned as an advisory?  

Finally it needs to be checked out, because if it fails, as stated by Pete Roper you will have gear oil all over the rear wheel and brake - not good.

Brian

The original recall notice -

[You must be registered and logged in to see this link.]

Brian

Who knows what the 'R' suffix means but I doubt it would mean 'Recall'. The only ways to find out are either to find a sympathetic dealer to run the numbers or pull the seal to have a look at the bearing. If it has 17 balls it hasn't been done, if it has 19 it has. The seal is sacrificial and pricey for what it is but it's better than being dead. As stated though I don't think this would be the source of your noise if it isn't leaking.