Twin gearbox troubles

Upstreeter

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Help! I had what I thought were failings on my part to select gears properly with a bit of jumping out of third gear. This became more frequent culminating in coasting to a halt with no gears being able to be selected at all. Removal of the outer casing (Gearchange side) and all looked ok. However, by sticking the indicator lever back on and trying to move it in either direction whilst rocking the back wheel to and fro I can get one gear (in roughly the neutral position) and another neutral beyond that. Other than this all is solid no matter how much I try and persuade the lever (albeit carefully). Am I looking at a problem with the vertical (bevel) mechanism or the camplate, or both? Worse, will the crankcases require parting? Any advice would be the most welcome thing in the world at the moment...short of an end to the war in the Congo, credit crunch, global warming etc.
 

petermb998

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One quick check is to check the cam plate spindle under the dynamo.
If this has come out this is possible your problem. (Broken Boss). I hope not.
I had this happen on a newly rebuilt engine which had not been run in, and all I had was top gear and a false neutral and I had to return home from work at Dagenham in Essex at 6.00am along the A12 to the Dartford tunnel when there was only one tunnel in the 1960s and on A2 to Rainham in Kent. 30 miles with only top gear going through the Medway towns.

If this is the case it will mean a complete strip down of the engine. sorry.
This happened to me 32 years ago on my 1st Vincent and I am sad to say although repaired I never got the chance to reassemble and run this Vincent.
I hope you have better luck.
best regards Peter
 

john998

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Twin gearbox

Hello, unless the bevel that is moved by the shaft with the indicator is damaged, or the casting that holds the cam plate bevel spindle has failed, you should not have to split the cases. It sounds like the gearbox is going to have to see the light of day, not as difficult as you might think. Remove the clutch and primary drive then the 10 1/4 screws on the round hatch. Also remove the kick start ratchet on the gear change side. In a panic I once did this and reassembled the thing between races at Cadwell.
A light clout with a soft faced hammer on the clutch shaft, on the gear change side will move the hatch. You will then be able to see the problem.
I do not remove the cam plate spindle, it is best left undisturbed. John.
 

bmetcalf

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It would be good to check the spindle, make sure it is tight and safety wire it to keep it from unscrewing.
 

pifinch

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Before you start pulling your engine to bits, please check your gearchange adjustment (Paul Richardson) It takes an hour or so & costs no money, if you have already verified this then I apologise for talking rubbish, but the easy option is the free option.
Steve
 

Upstreeter

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Thank you all so much for your trouble. It seems there are several options for visual diagnosis prior to major surgery! We've checked as per Richardson but nonetheless it is a valuable suggestion. Again, I appreciate you all sharing your hard-won knowledge.
 

Len Matthews

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Could possibly be a melted mainshaft Selector Fork. It's happened before mainly due the double gear's engagement dogs being worn or the oil level being too low. If so, no need to split the crankcase.
 

methamon

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Caution

Prior to removal of the primary chainase screws, do remember to de-tension the primary chain. I seem to remember reading this in KTB or Richardson over the weekend and failure to do so can result in damage?
 

stumpy lord

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It could allso be one or all of the steel pins in the selector forks having come loose , not an unknown fault.
stumpy.
 

Tnecniv Edipar

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As a matter of curiosity , when an engine is in bits being overhauled is there anything that can be done to reinforce the cam plate spindle boss ?
 
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