One another forum a mechanic who works on Guzzi's has brought to our attention that there is a hole in the bottom rear of the driveshaft housing the purpose likely being a "witness" hole. If the transmission or final drive seals leak, oil dripping out from the hole will be present alerting the owners to have it repaired.
He now feels it is working in reverse in that the hole allows ingress of water which rusts the shaft and splines and the rust abrades the seal causing it to fail prematurely. He makes a good case, your thoughts? Here are his 2 posts, if not permitted here just delete.
In the last few months we've had a couple of V85's through the shop with oil leaks out of the 'Witness Hole' I. The swingarm just forward of the bevelbox join. The first one I saw was on a bike that someone was 'Travelling through' on so we didn't have a chance to investigate but today a local bloke bought his in with the same problem.
To recap the issue there is an oil leak, currently not to serious, that manifests itself as wetness, (Rather than serious dripping, although the first bike I saw was worse.) which leads to dust and grime sticking to the case and everything back from the swingarm/bevelbox join.
The source of this leak externally is the small hole in the bottom of the swingarm just in front of the join. It's sole purpose seems to be to act as a 'Witness' hole to allow oil to escape and alert owners that their gearbox output shaft seal or bevelbox pinion seal is leaking. That's fine, apart from the fact that the hole also allows the ingress of water.
That water unfortunately means that the pinion shaft, splines etc. which are, needless to say, ungreased by the factory at assembly, rust. And that rust destroys the seal. The seal is, needless to say, not the same size as other pinion seals on previous boxes, (It's a 40x55x7 Viton seal.) so I'll have to seek them out.
Michael reckons they'll all do it eventually and the pinion shaft will need a lot of cleaning up. Maybe even a Speedisleeve. Design flaw but a good reason to address it BEFORE it becomes a critical issue.
Pull the bevelbox. Grease the splines lavishly. Then put some sort of temporary, removable, plug in the witness hole in the swingarm. Just add pulling the plug at every service and seeing if oil comes out. If it doesn't? Sweet! If it does? Time to go in further.
Well, as an addendum to my previous post regarding pinion bevelbox leaks you'll be overjoyed to know that most, if not all of them, are going to do it eventually.
The witness hole in the swingarm allows the ingress of water and because of the absence of any protective grease on the pinion splines or around the collar the seal runs on it gets rusty as buggery in there quite quickly.
On the bike we've just dealt with, (Partially.) there was also a small, (As in tiny.) amount of play in the pinion bearings that Michael reckons has been caused by the bevelbox taking a soaking and pulling some water in through the front seal. Anyway, whatever the cause, the fact is play in pinion bearings is a no-no so we're going to have to address that. The parts diagram doesn't show the actual construction of the pinion assembly but I'm guessing that unlike earlier bevelboxes the set up will be like the Cali 1400 where the pinion depth is set with shim/s under the bearing races on the register in the box. That's fine, the bearings will be generic and being constructed to ISO standards re-shimming won't be required. Of course the PITA is that the retaining collar for the pinion and bearing assembly requires a special peg socket, so I've ordered one of those but it probably won't be here for a couple of months. I reckon it's probably the same tool needed for the Cali 1400 boxes so that's a plus but for people in Oz I doubt very much if many other workshops will have the tool so if your bike has leaks you might want to contact us.
Anyway, our answer to the water ingress was to tap the witness hole and plug it with a small screw. Michael also polished the fuck out of the corroded collar that the seal runs on so it won't tear the new seal up and applied a ton of protective grease to keep moisture off it and the splines. As soon as the tool has arrived we'll get the customer back and fix the pinion bearings but hopefully the seal will hold until then. It'll be easy to check. Just take witness hole plug out. If oil drips out then the seal is buggered again but at least water and shite isn't getting in.
Personally I think he's probably correct and I'm going to plug mine. I checked and neither my California nor airhead shafts have holes.
He now feels it is working in reverse in that the hole allows ingress of water which rusts the shaft and splines and the rust abrades the seal causing it to fail prematurely. He makes a good case, your thoughts? Here are his 2 posts, if not permitted here just delete.
In the last few months we've had a couple of V85's through the shop with oil leaks out of the 'Witness Hole' I. The swingarm just forward of the bevelbox join. The first one I saw was on a bike that someone was 'Travelling through' on so we didn't have a chance to investigate but today a local bloke bought his in with the same problem.
To recap the issue there is an oil leak, currently not to serious, that manifests itself as wetness, (Rather than serious dripping, although the first bike I saw was worse.) which leads to dust and grime sticking to the case and everything back from the swingarm/bevelbox join.
The source of this leak externally is the small hole in the bottom of the swingarm just in front of the join. It's sole purpose seems to be to act as a 'Witness' hole to allow oil to escape and alert owners that their gearbox output shaft seal or bevelbox pinion seal is leaking. That's fine, apart from the fact that the hole also allows the ingress of water.
That water unfortunately means that the pinion shaft, splines etc. which are, needless to say, ungreased by the factory at assembly, rust. And that rust destroys the seal. The seal is, needless to say, not the same size as other pinion seals on previous boxes, (It's a 40x55x7 Viton seal.) so I'll have to seek them out.
Michael reckons they'll all do it eventually and the pinion shaft will need a lot of cleaning up. Maybe even a Speedisleeve. Design flaw but a good reason to address it BEFORE it becomes a critical issue.
Pull the bevelbox. Grease the splines lavishly. Then put some sort of temporary, removable, plug in the witness hole in the swingarm. Just add pulling the plug at every service and seeing if oil comes out. If it doesn't? Sweet! If it does? Time to go in further.
Well, as an addendum to my previous post regarding pinion bevelbox leaks you'll be overjoyed to know that most, if not all of them, are going to do it eventually.
The witness hole in the swingarm allows the ingress of water and because of the absence of any protective grease on the pinion splines or around the collar the seal runs on it gets rusty as buggery in there quite quickly.
On the bike we've just dealt with, (Partially.) there was also a small, (As in tiny.) amount of play in the pinion bearings that Michael reckons has been caused by the bevelbox taking a soaking and pulling some water in through the front seal. Anyway, whatever the cause, the fact is play in pinion bearings is a no-no so we're going to have to address that. The parts diagram doesn't show the actual construction of the pinion assembly but I'm guessing that unlike earlier bevelboxes the set up will be like the Cali 1400 where the pinion depth is set with shim/s under the bearing races on the register in the box. That's fine, the bearings will be generic and being constructed to ISO standards re-shimming won't be required. Of course the PITA is that the retaining collar for the pinion and bearing assembly requires a special peg socket, so I've ordered one of those but it probably won't be here for a couple of months. I reckon it's probably the same tool needed for the Cali 1400 boxes so that's a plus but for people in Oz I doubt very much if many other workshops will have the tool so if your bike has leaks you might want to contact us.
Anyway, our answer to the water ingress was to tap the witness hole and plug it with a small screw. Michael also polished the fuck out of the corroded collar that the seal runs on so it won't tear the new seal up and applied a ton of protective grease to keep moisture off it and the splines. As soon as the tool has arrived we'll get the customer back and fix the pinion bearings but hopefully the seal will hold until then. It'll be easy to check. Just take witness hole plug out. If oil drips out then the seal is buggered again but at least water and shite isn't getting in.
Personally I think he's probably correct and I'm going to plug mine. I checked and neither my California nor airhead shafts have holes.
