2016 1200SE - Clunky Gearbox

Hello Grisologists.

I've owned my GRiSO for 3 years now, and it's done 26K, the last 10K with me. It's always had a load 'clunk' when changing up and down gears, mostly Neutral to 1st, 2nd and 3rd. I've not really worried about it before as someone told me to "just ride it". But lately I've received some different advice, suggesting that I should look into it as it may get worse if not fixed.

It happens both from start and when hot, and doesn't matter if I rev match when down shifting - it always sounds like a brick bouncing around in the box when changing gears.

It's not the clutch (I assume) which is working fine. There's no gearbox whine when running, nor any other symptoms that I can think of.

Any suggestions (to do with the gearbox I mean )

Thanks in advance

Cheers Eric

How are the reaction rod bushing and spherical bearing! What year is it? whoops, sorry. Saw your tag line.

Could possibly be a too short clutch pushrod, but I doubt it if the clutch isn't dragging. If the clutch fluid hasn't been changed at least yearly it needs that but I doubt it would fix it.

Things like this are always hard to gauge without actually hearing them.

The noise on coinsedense, started as my trailer height went up by 3 inches. With it's new position I really have to rocket the bike in reverse to reach my driveway. I'll check that first. Isn't that possible catastrophic if that UJ floats around freely not being circlipped to input shaft at speed?

Also fresh silent block on reaction arm install.

Gootzibird13 wrote:

The noise on coinsedense, started as my trailer height went up by 3 inches. With it's new position  I really have to rocket the bike in reverse to reach my driveway. I'll check that first. Isn't that possible catastrophic if that UJ floats around freely not being circlipped to input shaft at speed?

I'm sorry, I cannot understand what you are saying. Is there a language issue in play here?

Sorry Pete. I was a bit under slept this morning. I drained and flushed carc today and found a lot of shavings on the magnet. And one piece was about 1.5x2.5mm. It didn't seem like a hardened metal shaving but definitely was the biggest I've seen in any of the magnets through the years on this bike. My question is this more clearly: can the UJ come uncirclipped off the main input shaft and cause damage?

I think the shaft coming unclipped from the gearbox output shaft is both unlikely and, if it did, would cause a lot of problems.

Is the bevelbox noisy? Usually crap in the oil of the bevelbox is a precursor to the pinion bearings completely loosing their preload and would set all sorts of warning bells ringing for me.

Was the oil that came out discoloured? Dark?

Firstly I'd stop riding immediately. Then pull the bevelbox off the swingarm and check the pinion nut to make sure it isn't loosing its preload. You can do this by looking down the throat of the seal holder and poking at the nut with a thin screwdriver. Any movement in relation to the pinion shaft indicates it's dumped its preload torque and needs serious attention. If there is muck in the bevelbox oil it may already be too late to save the gears but you won't know until you look.

If the nut has begun to loosen it is most likely there will be a load of oil inside the seal holder and at the back of the swingarm.

Check this and get back to me.

Oil looked cloudy from rain possibly with a silver hugh. The bevel itself has no noise or wineing watso ever. The feel of the wheel when spinning by hand is as always as it has been. As stated I drained than flushed then filled than drained again. Capped it to spec along with tranny as well. Went for short ride and shifted smother and easier quieter ect. But I'll be damned if it didn't make a single clunk as before ether inside or at UJ area. I don't know if you recall but I rebuilt the carc using the bevel out of a crashed Breva. Switched bevel and replaced the 2 bearings with what you recommended. And checked the nut and ring lock. Just switched it all into my original GRiSO final drive case. I will continue to troubleshoot as per your recommendation and let u know. Sure wish I took a pic of that metal fragment to show u but I didn't.

No, I didn't recall that part of the story. Drain the bevelbox again in 500 miles and see what the oil looks like but if it starts making any noise, especially on the over-run? Stop riding immediately!

Peeled back the boot and the UJ is securely circlipped on the input shaft. I will be commuting to work on it this weekend and will be cautious. 500 mile gear oil dump is going to happen soon. Let you know how it looks and/or any more noise.

I was planning on taking entire swingarm assembly apart for 2nd maintenance. Along with sending my shock in for refurb while disassembled this next summer. Will see how things go my plans may be expedited. Locking a wheel or grenading bevel box is nowhere on my schedule. The rebuilt CARC currently has 45,000 miles on it. And the bevel I used off a Breva had 14,000 if memory serves. She has been solid.

Ok Pete. As I had mentioned before after running new oil for roughly 400 miles I drained it again to check for fragments. This is what I discovered..... It made one clunk noise directly after new change but that's it. Nothing since no chatter or wineing or any types of sound of the new.[You must be registered and logged in to see this image.]

Nope, there's something seriously wrong going on in there. It's gunna have to come apart.....

Yikes!

I figured.

Shout out to new Guzzi pal "Kindoy" for sweet final drive replacement. Thank you kind sir. Up in the air and ready for basically a rear bike rebuild. I've been here before and those of you that can do this job in a few hours must have a skill set I will never have...Well into stage 1 of this process. (The Roper Method) I'm sure everyone wants to see the inside of that fragment filled final I'm replacing...[You must be registered and logged in to see this image.]

Well I certainly do!

Yep. I think I may crack it open. Interestingly enough if memory serves me there is a imperfection in the bevel casting itself that may or may not have something to do with this failure. Endless possibilities but I replaced both carriers bearings on this old Breva bevel. Both were FAG top shelf cartridges. The bevel has 59,000 miles and the bearings were replaced 45,000 miles ago on it. (As previously stated)....also a photo of my top box tool box. Pretty proud of it. Isn't it amazing how one accumulates so many tools over the years. Family hand downs or purchased, there never seems to be enough room in the toolbox...[You must be registered and logged in to see this image.]

Solves the mystery of what is root of failure....it was in fact the ring nut coming loose. You had mentioned there is a series of years or certain models that come loose and why? It's literally off of it's own threads and shredded boot. Tiny pieces of metal in the cavity below splined shaft. Messy....[You must be registered and logged in to see this image.]

Not really any particular model or year, it just sometimes happens. The cause would have to be either incorrect torquing or locking or, more likely in my opinion, the pinion bearings not being seated correctly or fully seated in the throat of the reactive bridge. If that is the case, with heat cycling they may *Settle* and in doing so reduce the preload on the nut. Once that is lost the only thing holding it will be the lockwasher and once the nut is loose it will rattle on the threads and eventually the threads erode and you end up with a nut that isn't! It's just a sort of 'Slip-fit' collar. By then the bearings will be thrashing about all over the place, the pinion will have side play and it will destroy itself in short order.

Usually by the later stage the box will make an awful noise on the over-run, you simply can't miss it.

Looking at the crap that came out with the oil I'm expecting the pinion, and probably crown wheel, to be toast but it's worth splitting the cases and having a look. If the gear teeth are OK it's rebuildable. Well, we'd do it. Dunno if anyone in the US would.

On a side note any defect in the case castings would have zero effect on anything as all the 'Important' bits are housed in the reactive bridge which is independent of the casings.

If it is buggered I'd be really grateful if you could send me the reactive bridge as I can harvest it for the 'Not sold as a spare part' shims to help rebuild other boxes in future. Splitting the cases is no big deal after which tooth damage will be obvious to the naked eye.

A couple of honorable mentions. The final drive just literally pulled off swing arm when backing out fasteners. I used (Hylamar M) not just there but on the Final drive case halves. Great product used by Rolls Royce on some of there case joinings during assembly. Never had any leaks...Also, notice bearing races of fork pin bearings are very clean and greased from last time I was in 40,000 or so miles ago. Pete you were right about the quality of that seal design. I would say stellar sir. Note* those are the original races....Notice splines on output shaft of trans are at 70,000 miles. Only product I ever use for splines lubrication is Molycote.Now all cleaned up, gotta repack my new bearings and reassembly is kicked off.[You must be registered and logged in to see this image.]

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Here's a fun fact I wasn't aware of... didn't know till this disassembly that you don't have to unload the preload on the spring of the shock. The manual states to remove the through bolt without that. Then I thought about it, the preloaded tension, adjusted by collar shortening, is all contained within the shock itself. And as bike is suspended there are no other forces applying to it...Ha Ha! And again I'm no mechanic......

Pete, a question regarding ring nut check. Does it spin with the splined shaft as shaft is rotates? And if thats ok you mentioned lock tight. Where and how exactly do you apply it? Do you have to remove the boot and clamp ect ? As a preventative, I'd rather not go through this again....

Yup, it has a very light preload, (There is no solid spacer between the bearings.) that retains it with the assistance of the lock washer. To apply Loctite you need the very thin, green, 'Super Wick-in' which I think is 279 from memory but check. You simply run a couple of drips of it down a thin screwdriver, bicycle spoke, or even a satay stick that will slip between the throat of the seal holder and the pinion shaft onto the threads at the top of the nut. A couple of drops is quie sufficient, you don't want lots of it slopping about down there! The Super Wick-in is designed to be applied to already torqued nuts and supposedly, as the name suggests, will wick down them before hardening to hold a bond. Does it work? Who knows but I haven't so far had a failure by loosening of any pinion nut we have so treated and it's ne of those things we simply do as a matter of course on any bike we have the swingarm off.

As for glueing the bevelbox onto the swingarm with Hylomar or whatever? We don't bother. It wasn't done at the facory on early bikes either but there were complaints by some whiners about oil misting around the joint so they fixed it by sticking it on with great globs of silastic making it much harder to remove the bevelbox from the swingarm.....Grrrrrrrr!