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V11 bevelbox, (Again!)

pete roper

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OK, so I've got one of these apart on the bench at the moment and I've found a couple of things that may be of interest to owners, things that aren't covered in the manual. I have a fairly good little digital camera and can take some pics and add a little shcpei with a few of my observations if people would like but I'm not clever enough to be able to post this sort of thing up on any website.


If I were to do this would any of you clever computer literate people like to stick it up somewhere for general observation and comment? If no one is bothered? No problem. But I thought I'd offer.



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OK, Jaap has kindly offered to post up some pics for me. Gimme a day or so and I should be able to cobble something together. Note this is not going to be a *definitive* examination of the box but there are a whole load of things that the factory manual doesn't tell you <_ .>


Oh, and if anyone here speaks Italian well could they perhaps contact Agostini's or Valpolinni's or someone and see if they can secure a price for the special tool for undoing the pinion bearing retaining nut? I'm ging to need one and when I spoke to the technical advisor at our importer today he seemed more concerned that I had managed to get his phone number than the fact I wanted to solve a problem on the product they are supposed to be promoting :angry: . My chances of being able to *do the right thing* and buy locally seem to be 'Buckley's and None' as we say over here.



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Pete, I allready made a drawing from such a tool, basicaly its a tube that you set in a milling machine and presto. And now when I think of it, take a pipe that fits just inside the nut. Then weld some small bolts( or metal pieces) on the outside that fit in the holes of the retaining nut. Way faster then waiting on anyone, see the drawing here.


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Actully Pete if you are intrested and someone has some pretty accurate drawings I can get a quote from a machinist at work his stuff is pretty good, think he charges around $70 an hour but basically spends his time knocking up odd jobs like this one. What material?

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Thanks guys, I could probably easily make something up myself, in fact in the interests of getting it apart I probably will, the main problem for me right now is time. I'm snowed under with work at the moment and really don't want to spend a couple of hours farting about making up a tool when I can simply buy it and write the money off as a business expense and get the taxman to pay for it! Anyway, I'll take some pics and write a bit of a blurb today about what you can examine without taking the pinion out!





Here are the pics and text Pete has sent me (Jaap)


This is the first time Colin and I have had the opportunity to have a dig into a bevelbox off one of the *new* six speed bikes. There is a fair bit of scratching around to be done to discover how it works and how it comes apart! Colin was crowing with excitement!




The first thing discovered when Colin pecked out the washer on the right hand side of the box was that there is a needle roller bearing in there. Obviously this is to enable the box to move in relation to the spindle as the suspension rises and falls. The inner race of this bearing also acts as a spacer, one of many, in the rear wheel, bevelbox, swingarm and spindle assembly. As can bee seen from this picture




there was evidence of rust and water ingress to this bearing which at first seemed odd as it is *sealed* at each end by rubber seals outboard of the bearing cage that should theoretically prevent the ingress of water or egress of grease by sealing against the inner race.


Closer examination of the inner race though showed that it has a drilling in





Why you would put a drilling in this race God only knows! There isn't going to be any grease going into that hole unless some is supposed to get scraped into it off a desperately over-greased wheel spindle. The only thing likely to get into it is going to be water, and that's exactly what it appears has been happening! Colin reckons it's got whiskers on it!!!!!


After prying off the crownwheel cover and crownwheel, (Which, incidentally, is a very snug fit in the carrier bearing. So snug that Colin left it well alone.) The pinion was exposed,




as can be seen, despite the wibbly-wobbly pinion that provoked this tear-down the teeth are in perfect condition, odd.


Looking at the outer crownwheel support bearing it can be seen that this is of a new design. The cage and needles no longer come out separately which will make it a right bastard to swap the outer oil seal, also visible in this pic:




Outboard of this there is another large spacer/washer and behind this the outer needle roller can be glimpsed.


Now, using his locally produced tool, (than you Reno!) Colin undid the castellated bearing retainer nut for the pinion. This is not torqued up particularly tightly, being a very fine pitched thread it doesn't have to be. In a crisis you could probably undo it with a pin punch or rapid blows of the beak





Colin now turns his attention to the crownwheel and it's shim, also visible to the left of the shim in this picture is the intermediate spacer from the centre of the crownwheel,




Note also the O-ring in it's groove of the crownwheel carrier, a much nicer solution than the old paper gaskets!


In the next picture, Colin indicates the 'Direction Hole' (with is 'Parson's Nose'.) on the new V11 crownwheel shims. This is there to aid the positioning of the shim, they holes in the flange that the bolts go through into the bevelbox housing are no longer symmetrical. This extra hole has to be aligned with the front of the box where the pinion goes in, then all the other holes line up.




Tomorrow Colin will make a bridge puller and extract the naughty,

wibbly-wobbly bearing and give it a good clucking at!


Until them 'Bye and 'Cock-a-Dooldle-Doo!'



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Colin the Chook had a bit of trouble setting up the dividing head to make the tool but other than that it was all his own work.


Never underestimate a rubber chicken!




Here's the rest (Jaap)



OK, now to the much more interesting stuff!


First thing this morning Colin made up a bridge puller using the main seal installation tool, a couple of V blocks, a length of 8x1.25 threaded rod a couple of washers and a nut. While the bearing/pinion assembly was in there tight it wasn't *that* tight but I wouldn't be game to try and pry it out from the inside.


Once it was out it was possible to look down the input orifice and have a squizz at the needle roller that supports the nose of the pinion.




Be warned! Given half a chance these needles will slip out of their cages! Whether this is a result of the lateral loadings being excessive due to the pinion being able to cant over sideways or simply that they are loose in the cage I can't say, but obviously be careful! immediately I noticed on trying to escape pushed it back into it's slot and clagged the whole lot in with a smear of good, thick, grease!


OK, so now on to the real crux of the matter. My initial thoughts on this oh-so expensive *special* bearing were that it would probably consist of a tapered roller thrust bearing and a ball element rotational load bearing.

Well I was quite wrong! Without taking the pinion out, which I didn't want to do as if I did I'd almost certainly have to replace the seal and possibly the *very Expensive* bearing, It is hard to see that under the large and clearly visible ballrace there is in fact a caged roller bearing. It would seem that these are not a tapered roller but just a standard, tubular, needle roller. These are what take the lateral and rotational loads, the end thrust is taken by by the big ball race. The interesting thing is that the

ball race has a split outer race,






In the first pic you can see the rollers underneath the balls, outboard of the balls is the seal which fits inside the castellated retaining collar. The collar has an o-ring on the outside to seal the collar in the box and the seal fits tightly inside the collar and bears on the pinion shaft beneath the retaining nut. This ensures there is nowhere for the oil to escape from the box. In the second pic you can see the outer part of the split race which fits over the balls but beneath the retaining collar. As the collar is

tightened down it clamps the two parts of the outer race together and because it is going to be ground to a super-critical fit to ensure the correct bearing clearance when the castellated collar is tightened down the two halves of the race will mate ensuring that the correct amount of end float, and therefore lateral play in the pinion, will be available to ensure not only adequate clearance for lubrication of the bearing but also correct clearance to allow only minimal run out of the shaft of the pinion while under load.


OK, so why is there excessive run-out and lateral play in so many V11 boxes?

Well, Colin's theory, (And who am I to disagree?) is that when the boxes are assembled they are all put together and torqued down to the *correct* specs.

The problem stems from the fact that in service bearing races tend to *settle* into their registers. I know from putting this unit back together that the bearing is a tight fit, you can't press it in really easily due to there not really being any flat surface you can use as the base to press against. In the end I put the pinion/bearing unit in the deep freeze for an hour or two and warmed the case with a butane torch, (Not too hot! I didn't want to damage the inner crownwheel seal! Or damage the paint.) Then by quick sleight of hand I was able to drop the bearing into the housing and get it in deep enough that the inner race of the *nose* bearing engaged with it's needle race after which I was able to use a hide mallet to tap it down to it's register. I wouldn't use a hammer here, you'd damage the balls!


Once it was back in I lubed the o-ring on the castellated collar, copiously, with rubber grease. Dropped the separate part of the split-race onto place and tightened down the castellated collar. As you do this you effectively clamp the two parts of the race together. No doubt there is a *specified torque* but I just tightened it up until it wouldn't tighten any more by hand. I wouldn't worry too much about the torque, although I'll look it up tonight, It's bound to be pretty high as you are using a fine pitched thread to both clamp he two halves of a bearing race together AND seat the entire assembled double-bearing onto it's register in the box. It's a typical and very 'Guzzi' solution to a problem. The end result was that as I tightened it down, not surprisingly, the end float disappeared! By the time I'd got it to 'Cut washers off it' tight with the two stubby handles of my home made tool the lateral play had been reduced to no more than the suitable backlash in a set of bevels, ie0.1 to 0.15ish mm. Warm it all up a bit and I reckon it will be tickety-boo and honky dory!


The bottom line, (Or perch, as Colin would say.) is probably that if your pinion has excessive run-out simply remove the box, get a castellated nut tightening tool, (Reno, a local retired toolmaker in Bunged-end made mine for $60AU!) and try tightening it down a bit and seeing if that removes the end float. It is a whopping great bearing so running out of it's correct clearance probably won't do it any harm for a while but even so it's far better for it to be *right* and if you can do that without stripping the box like I did? Bonus!!!!!!!


One final point. The oh-so expensive bearing? While I didn't take it off and accurately measure the balls, rollers or overall dimensions I really can't see any real reason why it has to be this hideously complex design. It may well be that the pinion shaft size or whatever is something really odd but when I get one in where the bearings *are* stuffed or the CW&P are rooted I think I'll be taking a trip down to the bearing shop and seeing if I can find a pair of bearings, one a needle roller and the other a bloody great ball-race, that when used together have the same overall dimensions as the Oh-so expensive factory bearing. If some clever engineer type can come up with a reason why this *wouldn't* be a suitable solution could they please tell me? As far as I can make out though if you could get bearings with suitable clearances and load bearing capacity that will fit it could save an awful lot of money. And let's face it, that's the 'Guzzi Way'!!!!!!!!!






Colin the Chook!

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