Speedo cable leak 59 VH

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tonyh
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Speedo cable leak 59 VH

Postby tonyh » Fri Mar 08, 2013 5:00 pm

Ok guys. I have run Ariels for almost 40 years and they always leak out of the speedo cable under the front of the gearbox.

Over the years I have tried all sorts of stuff , extra "O" rings, sylicon etc all I have done is slow it down a little.
Short of not putting oil in (joke) has anybody done a better mod without major machining to cure this.

Cheers Tony

robin.parker
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Postby robin.parker » Fri Mar 08, 2013 5:18 pm

Heat Shrink Insulation tubing, to cover part of the metal ferrule and to extend along the cable to above the gearbox oil level. I found some on ebay, otherwise "Vehicle Wiring Products" sell it. I'm sorry I can't remember who, on this forum, told me the tip, but it works!!
Good luck,
Robin.

Simon.Gardiner
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Postby Simon.Gardiner » Sat Mar 09, 2013 12:15 am

Weeeell, the very slow weep from the speedo cable doesn't pee me off anything like as much as the perpetual mist from the exhaust lift lerver that slowly but surely turns the whole top of the engine into an oily mess!

(I've tried new washers, and O-rings, the only working solution so far- also in 40 years - has been to take it out and replace it with a large bolt....)
'55 Huntmaster, '56 VH, ' 51 VH, '80 R100RT, '00 Sprint ST (but all those Ariel parts can only make one running bike...)

pete.collings
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Postby pete.collings » Sat Mar 09, 2013 11:31 am

It is possible to considerably reduce the oil mist blowout from the valve lifter by fitting an oil seal. This involves carefully turning out the fitting in the rocker box to suit the oil seal (a conventional sprung seal), and checking/adjusting the arm so that it does not rub against the seal. You need to strengthen the return spring, if using the original volute spring I used the alloy screw on cap of a sparking plug, with a hacksaw cut to fit it in place, and squeeze it closed when in position.

I can't remember the exact dimensions of the oil seal used, but a check in a seal catalogue (or ask a supplier) should provide something suitable.

A common problem with leaking valve lifters is wear caused by incorrect adjustment, ideally they should only touch the rocker ledge at the very end of their travel, only a small lift of the exhaust valve is needed to release compression pressure. If incorrectly adjusted, there is a danger that on valve closure the rocker arm can touch the lifter eccentric peg, and the loading will wear the spindle and allow/increase oil leaks. It will also make an annoying clattering noise!
I have also seen differences in the length of the eccentric peg, and if the washer/sealing gasket on the spindle carrier nut is too thin, the end of the peg can catch the rocker arm, if too thick the peg can slip past the rocker ledge, and in the worst case cause the rocker to jam and prevent the valve opening. If possible, check the clearances before replacing the rocker box, when the relative positions of the lifter and rocker arm are clearly visible.
I have seen the latter case when a rebuilt motor with a different exhaust rocker box was run for the first time, using the valve lifter to stop the motor prevented the motor from restarting.

Fortunately, new valve lifter assemblies are available from club single spares, or from John Budgen, if you find your lifter is worn.

Of course, if there is a lot of blowby from the piston rings, then this can overwhelm any attempts at making a motor oiltight.

tonyh
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Postby tonyh » Sun Mar 10, 2013 9:44 am

Thanks Simon. I will give the heat shrink tube thing a go. I do have some of this. As regards the valve lifter I have a breather on the rockerboxes which takes the preasure off the lever hole.
Cheers Tony

david.anderson
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Re: Speedo cable leak 59 VH

Postby david.anderson » Mon Mar 11, 2013 8:03 am

Shrink wrap is the best method to stop oil leaks from the speedo cable ferrule. I have been using this method for over 10 years.

With regard to oil out the valve lifter assembly it is also an easy job to fit an O ring. Remove the large nut and turn a recess in the end of the nut around the shaft hole to take an appropriately sized O ring, set so the O ring will just stand proud of the recessed flat. Discard the leather washer and turn a brass (or steel washer) to the thickness of the original leather washer and backing washer. The new brass washer fits tight against the O ring and is then shimmed in the original manner so as to hold a little tension against the O ring. I did my valve lifter assemblies around 10 years ago and have not seen any oil mist since and have not yet replaced an O ring.
David


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