Whining Bevel Box

I have a 2015 GRiSO 1200 SE with a very whiny bevel box. I let a friend ride it, and even with a Mistral pipe w/o the db killer in it, all I could hear as he motored away was the bevel box whining. At the 800 mile mark, I changed the rear end lube and only about two tablespoons came out. So much for dealer prep! I changed it again at 1000 miles and the fluid looked like metal flake paint! I just changed it again at 4000 miles and there was hardly any metal in it. I'm just wandering if this noise is one of many that this beast makes in it's entertaining cacophony of moving down the road, or if I should go beat the dealer over the head to replace the bevel box due to future problems. Thanks for any input.

Oh for fucks sakes!

No oil? Bevelbox dead in 5 miles. No if's or buts, (Believe me, I did it once, many years ago, but for another reason on a different bike.)

You may have a fight on your hands as to *Who* is responsible for the damage but the bevelbox will be fucked, and I don't care if they take it to bits and tell you it all 'Looks Fine'. You can't run a right angle bevel drive without lubricant. If they tell you otherwise they are either idiots or lying.

Other possibility is the pinion nut has dropped its preload but with no oil? I doubt it.

DO NOT RIDE THE MOTORBIKE UNTIL THIS HAS BEEN ADDRESSED PROPERLY. YOUR LIFE MAY DEPEND ON IT,

Pete

What's the preload value on the pinion cover/seal? The manual has fuck all on it! Thanks

Can't remember offhand but 'Till you fart' tight is right, if you mean the castellated seal holder locked with the G clip? Have you got the bevelbox apart?

Pete

I don't currently have it off, but I did last weekend when I took the swingarm off for a lube job. I had to take the bevel box off to reinsert the driveshaft. Would too little preload show up as end play in the pinion? And, is the cover/seal with the clip not the place to apply preload? I called the dealer today and they said 150Nm for the pinion nut itself. That should squeeze one out!

Arrrrgh! NO, NO, NO!

Firstly, if your bevelbox has been run for any time at all with no oil in its fucked. No ifs or buts. Don't bother taking it to bits yourself because if you do you've just done your warranty.

Secondly there is no published torque figure for the pinion nut because the reactive unit is not supposed to be serviceable. The pinion bearings are NOT solid spaced, if you tighten down the pinion nut to that figure you will lock and crush the rollers if you don't strip the nut first. That figure is for the seal holder which is on a very fine thread and simply locks onto the outer bearing. The preload for the collapsible spacer between the outer races is supplied by torquing the pinion nut. That has no figure for the reason stated before but industry standard for such an application is generally about 40-50 inch pounds. To be honest I pretty much 'Guestimate' it and use blue Loctite 243 and wick-in to supplement the lock-washer. (N.B. The lock washer and nut are also not listed as available parts but are in fact the same as the peg nut and lock washer used for retaining the crank sprocket for the timing chain of a T3/LeMans from the mid/late seventies.).

To perform ANY work on the reactive bridge and crownwheel and pinion assembly you have to split the CARC cases and to do this safely you'll need a heat gun and a press. If you don't have experience in or knowledge of differentials or spiral bevels I really recommend you leave it up to your shop, especially. As your bike is new and hopefully still subject to warranty.

Also to get the driveshaft out you would of had to pull the swingarm. Did you lube the Swingarm bearings? I hope so.

Pete

Yes, I did. That's why I removed it. The swing arm bearings were fine, but I cleaned and re packed them, anyway. The suspension bit's needle bearings were dry as a popcorn fart, so they got a dose of greasy love. The bevel box had a little bit of oil come out at 800 miles, and I've changed it twice since then. It now has 4200 miles on it with nothing but the whine. Shouldn't it have failed already if it were going to? I'll take your advice and let the dealer futz with it. Sorry for all of the dumb questions, but I'm new to the magic of Moto Guzzi.

The whine is because the gears are trashed. You can't run spiral bevels dry. Just because they are currently delivering drive doesn't mean they are safe.. If a tooth gets spat off either the crownwheel or pinion it can jam between other teeth and lock the back wheel. Death or serious injury is a very real possibility. Hence my instruction NOT TO RIDE IT. REALLY, I'm not kidding.

Pete

Delivering a bike like this is negligence of the worst kind. Really and truly apalling. You should write to Piaggio in New York. They may ignore you completely, but I'd do it anyway.

Hopefully with the gear whine/damage occurring within 1 year of new, you need not even argue about who did what?