Further to my earlier queries re the oil not returning to the oil tank, and again thanks for all of your help, the pre-unit engined and gearboxed, Triton now starts and runs well. However, oil now pours out from around the gearbox sprocket area between the primary chaincase and the gearbox, it is not any of the oil pipe connections or a split tank as I have checked all of those and I am sadly convinced that is coming from the gearbox main bearing, the oil is very clean and the gearbox oil is now low - I did put new clean oil in. When I bought the bike the gearbox was empty and perhaps now I know why, this was despite the chap I bought it from having paid £3,000+ for an engine rebuild but perhaps this not include the gearbox. Does anyone know whether this is a common pre-unit gearbox problem and is it an easyish fix? I doubt it, oh wo is me. Thanks, Ken
Seems as though you are pretty certain it's the gearbox side of the sprocket that's leaking. The gearbox emptying though is a bit of a concern. There's an oil seal pressed into the gearbox from the sprocket side that seals onto the high gear (Small stones get caught in the oily area around the chain sprocket and wear the seal). Sometimes oil can leak along the splines of the high gear as well. Would a leaky sprocket oil seal empty the gearbox that quickly? What about the layshaft blind needle bearing just below the sprocket, or the plug sealing the fork selector rod? Have a close look to check. The beginning of this video shows him spinning the high gear by hand in the gearbox against the oil seal. The sprocket screws directly onto the high gear and will need to come off to gain access. I've never tried to replace the seal without dismantling the gearbox. Someone may be along shortly to advise you about that. But you'll need to remove the whole of the clutch to gain access to the sprocket to remove. I'd dismantle the gearbox anyway just to check everything. The video above will show you how to reassemble the gearbox as it's a bit fiddly but easily done with a bit of patience. I think people get fed up with their bikes once they've spent a wedge on them and they still have problems. Unfortunately that's the nature of these beasts, you really need to climb into them yourself or find someone who really knows what they are doing (they are around but they are mighty busy). Get stuck in, you'll find your way around it......
I have been told by Ged, the very helpful chap from Skye Classics, that this is more likely to be wear on the mainshaft gear causing the bush to get chewed up, sadly to check this I think that it will be a complete gearbox strip! Thanks for the video, this will come in handy. I have completely stripped a Norton Dommie gearbox before including replacing the bearings insitu but Triumph gearboxes are new to me.
Ok, sounds like you are going in for a look. That's the main thing, there's nothing too difficult, it's just a bit fiddly rebuilding. (5 speeds are much easier - just sayin ). No rush, you've got a few other nice ones to ride while this one is in sick bay. Keep us updated if you can
Hi Iron, I have now stripped the primary chaincase side down, it was a bit tricky as someone had tightened the clutch and crankshaft nuts up so tight and also the projecting "boss" on the engine had, for some reason had the inner chaincase "burred" over it for part and the inner chaincase would just not waggle off. In the end I had to carefully chisel the excess aluminium away to get it off. There is noticeable play on the gearbox shaft although it is not excessive, you can see oil from between the bush and the shaft but I think that the main play is at the gearbox. I will take the sprocket off as long as I can get the big nut off, the handbook does not say anything about this nut being LH thread so I am assuming that it is a normal RH threaded nut. Cheers, Ken
Yep, normal RH thread (Harleys are odd like that and catch us Triumph guys out sometimes ). When you come to rebuild get some threebond or similar onto the splines when doing the nut up as oil can make it's way through there. This is a T140 unit but very similar, I've piled it on before fitting the tab washer
Hi agai Hi again, I eventually managed to get the gearbox sprocket off by making up a special/adapted spanner at attached picture, the spanner is a ring spanner and fitted nicely all round the sprocket nut and the spanner is stopped from coming off by a spacer, the clutch centre and its nut but boy was the sprocket nut on tight, not sure whether this should be so tight, the chap who put this together did use Three Bond or similar on the splines onto which the sprocket fits, and almost everywhere else. There is slight play between the bush and the mainshaft and the main shaft and the bearing so I think that I will have to go the whole hog and now strip the whole gearbox. Thanks again, I will let you know how it goes. Cheers, Ken
