Author Topic: Lyta tank / galvanic corrosion?  (Read 787 times)

Offline tiggy

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Lyta tank / galvanic corrosion?
« on: 04.12. 2015 18:04 »
Has anyone got experience of problems with galvanic corrosion on a Lyta or other make of alloy tank?
I am fed up with the problems caused by modern ethanol fuels on original steel tanks and would prefer buying an alloy tank to using a protective sealant. The 5 gal. Lyta tanks are now very expensive but in my view look great. My concern is I have read you can get a reaction with aluminium coming into contact with other metals so wondered if anyone who has fitted an alloy tank has advice. The frame rubbers and centre bolt bung stop direct contact between tank and frame but that still leaves the front plate.
Thanks

Offline Klaus

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Re: Lyta tank / galvanic corrosion?
« Reply #1 on: 04.12. 2015 18:15 »
hi Tiggi,

I have alloy tanks on my racers and there is no problem with modern fuels.
In winter times the tanks are empty and dry, but only the bikes have her place in the lobby *whistle*

cheers Klaus


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Offline BSA_54A10

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Re: Lyta tank / galvanic corrosion?
« Reply #2 on: 15.12. 2015 07:26 »
To get galvanic corrosion you must have a complete circuit.
So the dissimilar metals must have a good electrical contact and then both of them need to be in an electrolyte to complete the circuit.
This is a lot harder to achieve than most would believe.
Further more in a galvanic corrosion situation, it is the iron that corrodes, not the aluminium so it would be the tank mounting bolt.
However the bolt & tank never come into contact due to the rubber bung so that leaves the front tie strap and the brass fuel taps.
Brass & aluminium rarely react.
Well to be honest , they react quickly then form very stable oxide so all corrosion stops so that rules out the tap/tank interface.
The tie strap rarely would be wet enough to complete the circuit but if you are worried, fit a stainless strap & bolts.
Bike Beesa
Trevor

Offline unclerob

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Re: Lyta tank / galvanic corrosion?
« Reply #3 on: 15.12. 2015 10:02 »
I'm not sure this is really relevant but I do quite a lot of work on boats and you do sometimes get very noticeable corrosion between aluminium and stainless steel....for instance using a stainless rivet on an ali mast.....I have a tub of goo that's used specifically to coat fittings before they're assembled but I've had it so long the labels fallen off and I've forgotten what its actually called!!

Online RichardL

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Re: Lyta tank / galvanic corrosion?
« Reply #4 on: 15.12. 2015 17:00 »
You could try coating surfaces where aluminum meets other metals with antioxidant compound such as one of these: http://www.idealind.com/prodDetail.do?prodId=noalox&div=5&l1=accessories

These compounds are used where aluminum wire is terminated to copper lugs to prevent corrosion from increasing resistance and, therefore, building-up heat. Though basically intended for aluminum to copper connections, I see no reason why it would not do the same job for aluminum to steel.

Richard L.
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Offline BSARGS650

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Re: Lyta tank / galvanic corrosion?
« Reply #5 on: 16.12. 2015 00:24 »
I have a genuine Lyta tank on my RGS, it has a stainless support strap fixed underneath attached with stainless fasteners with copper grease (I think the product is Kopper Kote) on the threads since 1987 and have not witnessed any corrosion in the many times it has been removed and reinstalled.....

Offline tiggy

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Re: Lyta tank / galvanic corrosion?
« Reply #6 on: 16.12. 2015 10:57 »
Thanks for all the helpful replies. I feel much happier splashing out a lot of money on a Lyta tank knowing it is likely to see me out with BSARGS650's tank still going strong after 28 years. Just got to find one now! Curious as to the multiplier for todays prices compared to 1987, quite a large difference I would guess.
Thanks
Rob

Offline BSARGS650

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Re: Lyta tank / galvanic corrosion?
« Reply #7 on: 16.12. 2015 12:26 »
Hi tiggy....I actually bought my 5 gallon Lyta tank from B.G. Hichisson, Lyta Works, Dartford in October 1981 for £89 - a lot of money then, but the quality is superb!  It cost me more then the RGS bought a couple of years previously....The RGS project was a bit of a slow process due to various, not restoration reasons, and was finally completed in 1987.  The RGS also has a Dow central alloy tank as seen in my intro to this super Forum.  I have other Dow alloy stuff not fitted yet; Superleggera top yolk, primary chain oiler and reservoir......Good luck getting a tank!

Offline Topdad

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Re: Lyta tank / galvanic corrosion?
« Reply #8 on: 17.12. 2015 12:07 »
Tiggy, back in the early 1970's I was working for a company called Cundalls in Liverpool selling Bikes and  aguy I knew entrusted his DBD34 Goldie to me for sale on a commission only basis. This beautiful beast had a Lyta tank   *loveit* and it really set the bike off plus was extremely comfortable, you just moulded to it . Not so sure that would be the case now at nearly 66 but  I really hope you find one, best of luck ,Bob
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