The gearbox on my 850T has given up on me! Lost second gear last week - a terrible crunch going up from first and lots of pedal pressure needed to engage it. Got me home of course but now I need to fix it. Crabbing the frame and getting the box out is fairly straightforward but now it’s on the bench and I’ve read the manual getting inside looks a bit daunting. There seem to be a few special tools needed including a large press. Would it be wise to pass the box on to an expert or can I manage in my workshop with a decent array of tools? If I need to farm it out, any suggestions for a mechanic to do the job? I’ve heard Baldrick is very good and not too far away (I’m in the south east).
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Nick, if you get stuck i have plenty of Gearbox spares and the tools to do it. I’m in Chichester
Nik 07980 639289
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Many thanks Nik. I’ll have another read of the manual and mull it over. It’s the specialist tools that are putting me off but if you have them, it may well be doable!
I stripped and rebuilt mine a few years ago and it wasn’t too bad to do so long as you work very carefully and keep things in order.
You will need a peg spanner to remove the clutch boss nut, available here
Plus a deep socket to get the output nut off. A bit of ingenuity was required to lock up the box when undoing those 2 main nuts.
I used a very good guide written by Pete Roper on The Guzzitech
https://www.thisoldtractor.com/guzzitech.dk/gb_en_complex-technical_gearbox-shimming-pictures.htm
This is what you can expect to find inside when it is all laid out on the bench.
Another link to a similar article
https://www.thisoldtractor.com/guzzitech.dk/gb_en_complex-technical_gearbox-rebuilding-pictures.htm
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Thanks Don, that’s encouraging. I already have the peg spanner from replacing the clutch, and a deep socket is easy to find. I’ll read the article and probably give it a go over the winter. I expect to find more shrapnel than is in your photo!
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You know it’s worth getting your fingers oily Nick!
Best of luck, we must catch up again some day. I saw Noel last weekend, not a lot of change with him. Have fun!
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Thanks Chris, the gear box is out, cleaned and part stripped. Not as intimidating as I thought - so far…! I’ll pop up for a beer when the sun shines again.
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Let me know if you need an end cover gasket and any of the O rings etc as when I ordered parts for my rebuild, they sent packs of 10 of most things!
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Many thanks Don, I’ll probably take you up on your offer when I find out what I need.
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If you get stuck Im in Ashford and I have a press but I don’t remember having to use it. The tools I needed and dont have were the blind bearing pullers but I improvised with rawl bolts.
I do however have a bent piece of wire which was invaluable for putting the selectors in to place
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That’s good to know, I’m over near Tunbridge Wells so not far away. A previous owner has had a go at it and massacred the speedo drive so I had to resort to Mole -Grips to get it off. Heaven knows what else I’ll find when I get the lid off. I have a feeling it may be a long shopping list! Thanks for the offer of bent wire tool!!
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In fairness, they made the speedo drive body of really, really soft brass. My speedo drive was mangled when I got it 30 years ago, I think just from replacing the cables. Best thing to do is buy a new one ( I think the bodies are made of better metal now ) or file undersized flats on it now that you’ve got it out. I did this recently, and was shocked by just how cheesy the brass is. I finished off the resizing by broaching the flats with a normal open-ended spanner, by hand. It really didn’t need much force, so warning is, you need to be gentle when doing it up/undoing it.
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Thanks Andy. Yes, the brass screw is super soft and has been biffed off with a hammer and drift at some point so I think it’s time for a new one. Stein Dense seem to have them at about £50. I’ll add it to the growing shopping list.
Having removed the end cover with ease (the output shaft has a nut which should have been torqued to around 120 lb-ft but which was little more than finger tight! Tabbed down so it hasn’t slipped) I have found that the output shaft bearing has disintegrated and trashed the splines so the gears won’t come off. This could be expensive…
Very helpful article, better guide than the Haynes manual! Thanks Don
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I think that the speedo drive is quite common to many bikes over many years, even my 1965 Stornello has one very similar.
The Lambretta ones look very similar, have a good look at this and compare it to your old one. I wouldn’t be surprised if it would fit. Search ebay for Lambretta speedo drive for other listings.
Thanks @Don-Spada . It certainly looks the same and is a hell of a lot cheaper than the guzzi part. Might be worth a try if I can get the rest of the box sorted - it’s in a right state!
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Nick, I think I have speedo drive you can have. Its off a SP1000 with 7/33 rear drive.
I can’t check until tomorrow evening, though.
That’s very kind, thank you. I’ll hold off for a while as I’m away for a few days and I’m not yet sure that the box is salvageable or if I need to source another from somewhere. The engine block is from a late model Spada judging by the engine number (VG prefix). I’m not sure what the difference is between gear ratios on the models, so a bit more research is in order. The output shaft has damaged splines where the bearing sat, the bearing is toast and at least one of the selector forks is broken. There may be more but I haven’t got it completely apart yet.