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Alton/Generator Oil Leak

Martyn Goodwin

Well Known and Active Forum Website User
VOC Member
Lovely 150 mile run today on the Comet, just purred along – butyet another pesky oil leak – so small as to not be noticed in the oil tanklevel but sufficient to be noticed all over the left side of the cases, theAlton and the front of the gearbox.

I figure it’s coming from the joint where the Alton abuts thecases. There is no gasket there and no means of clamping to “pull” theAlton up against the face of the case.

What I did when I installed the Alton was apply a generouscoating of Hylomar blue to both the case face and the mating Alton face then whileapplying pressure by hand to hold the two faces together, tightened up thesaddle clamp – then I left well alone for 24 hours to “set”. Well – as Isaid – still leaks.

What have others done to solve this issue? FWIW I AM NOTprepared to use silicon anywhere near the motor. Martyn
 

nkt267

Well Known and Active Forum Website User
VOC Member
Alton recommends sealing with Silcone(bathroomsealant).
This is what I have done and it allows you to adjust the clearance for the drive gear before you leave it 24 hours to set..John
 

1660bob

Well Known and Active Forum Website User
VOC Member
I am considering this issue at present whilst building my motor.My Vin has yet to run, so i cannot claim experience, but my thoughts are thus:
The Alton, we have to assume is good to go- i.e. will not need any attention to itself for a good while (apparently not always the case!) the reason i say this is that, as i look at it, the only way to stop an oil leak here is to virtually glue the faces up real good -what else is there? Thus fitting of the unit i consider semi-permanent, and all positional adjustments must be settled before the "glueing " takes place. To this end, i managed to turn up an alloy distance collar with a superthin boss on it(and I mean thin-there is only a few thou to clear the Alton sprocket carrier ) that was a nice press fit in the end of the Alton.I glued (Wellseal)/pressed this in and can now consider it "part" of the Alton so that , as far as my bike is concerned, the axial position will always be right as soon as the faces abut when the generator is offered up. I have marked the Alton casing with two tiny centrepunch marks adjacent to the outer edge of the ET176 clamp, upon which i have scribed a reference line.The two punchmarks represent the extremeties of turning ajustment available to adjust tooth depth (there`s not much) before the Alton begins to push itself away on the crankcase "slope", (and open up the joint we are trying to seal), All this done, i now intend to use a good, flexible sealer (Threebond 1184?) but i suspect silicone will do the job a lot more cheaply, and no oilways in the primary to worry about should a bit get in). My primary has a crank seal fitted to hopefully stop it pressurising from the engine, and may be OK fully sealed (as my MK3 Commando was with no ill effect) but perhaps a small breather in the inspection cap may be wise? That`s my take on it,Bob.
 

Black Flash

Well Known and Active Forum Website User
VOC Member
I cannot say for sure how my Alton sealing will be on my 600 cc TPV Comet engine as I have other things to do before I can register the bike.
But there is one thing I know for sure, you should not have any issues you describe with a Comet engine as long as your breather is working correctly.
And there are a few modifications that will make it work even better.

First open up the window in the breather bush by filing. the correct width can be found in some of the many publications. I seem to remember that it has to be around 11 mm, but this is from memory, please check first.

Second time it correctly as in Richardsons handbook.

Third, instead of an eyebolt and banjo I fitted a thin walled 90 degree angle piece with the correct thread. I had to make it myself, but I am sure you can buy it from a plumbers shop in England. then I used a short length (8 inches) of rubber pipe to it.
this way there is no restriction in your breather system and there should be absolutely no build up of pressure so you have no oil coming out of your Hylomar sealed joint.

That said your engine (especially bores and rings) need to be in good condition. but then again using any other sealant you may as well just be hiding a problem that lies deeper within your engine.


Hope that helps
Bernd
 

b'knighted

Well Known and Active Forum Website User
VOC Member
Surely all these extra sealing processes should be superfluous on a Comet where the dynamo drive gear is centralised in a Gayco seal. I think that ClevTrev has pointed out that this should be the starting point for setting up the timing chest. Please tell us the full sequence again Trev.

Bernd's breather setup does sound like the way to go if there is any pressure problem.
 

nkt267

Well Known and Active Forum Website User
VOC Member
Surely all these extra sealing processes should be superfluous on a Comet where the dynamo drive gear is centralised in a Gayco seal.
The newer Altons for a Comet do not use the original drive gear,the use a nylon type gear similar to that used on a dynamo for a Mag/dyno set up.Even on the older ones that used the original drive gear it was recommended that the seal be left out and the body sealed to the crankcase with sealant..I've had both types..John
 

b'knighted

Well Known and Active Forum Website User
VOC Member
Sorry, I've never owned one of these new fangled things so I didn't realise that the successful method of mounting and driving without leaks had been superseded. I always thought the original sealing on the Comet was vastly superior to the approximate sealing used on the twins.
 

Black Flash

Well Known and Active Forum Website User
VOC Member
" I didn't realise that the successful method of mounting and driving without leaks had been superseded"

this is the kind of humor i love you Brits for !
Bernd
 

ogrilp400

Well Known and Active Forum Website User
VOC Member
Trying to work out why a proper oil seal would be left out in favour of slopping goop all around the alternator?

Phelps

The newer Altons for a Comet do not use the original drive gear,the use a nylon type gear similar to that used on a dynamo for a Mag/dyno set up.Even on the older ones that used the original drive gear it was recommended that the seal be left out and the body sealed to the crankcase with sealant..I've had both types..John
 

Martyn Goodwin

Well Known and Active Forum Website User
VOC Member
Trying to work out why a proper oil seal would be left out in favour of slopping goop all around the alternator?

Phelps
 
As I understand it , The original generator gear is steel and provides a perfect surface for the viton seal to seal against.
The gear for an alton is plastic and it is my understanding that the viton seal , if used, would be quickly destroyed. Thus the use of "sealing goo"
Any opinions to the contrary??
Martyn
 
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