Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: mickwinf on September 24, 2014, 08:23:32 PM

Title: de rust a petrol tank
Post by: mickwinf on September 24, 2014, 08:23:32 PM
my 500 has got lots of crud getting through to the carbs causing blockages. I have cleaned tank and it is pretty good inside except for the seams and the odd spot of rust. I have read that vinegar will dissolve rust but is this true? or any other method that is proven to work. I don't think it is bad enough to need a sealant so look forward to your ideas.
Title: Re: de rust a petrol tank
Post by: hairygit on September 24, 2014, 08:27:42 PM
A cheap brand of cola drink in the tank and left overnight. It contains phosphoric acid, which converts iron oxide (rust) into iron phosphate, a hard black inert material, it's basically the main ingredient in organic rust killers such as Jenolite, but much cheaper! :D
Title: Re: de rust a petrol tank
Post by: JustcallmeMrT on September 24, 2014, 10:15:55 PM
I rigged up an electrolysis unit to clear the rust from my tank, and it worked a treat.  Might not be worth it for a small quantity of rust though, but worth considering.  Google electrolysis petrol tank and you should get a load of hits
Title: Re: de rust a petrol tank
Post by: mickwinf on September 24, 2014, 10:56:18 PM
I like the idea of cheap cola Hairygit, as the rust is mainly in the bottom seam it might lead to a leak if the rust was completely removed by the electrolysis method.
Title: De rust a petrol tank
Post by: Lobo on September 25, 2014, 01:15:16 AM
Hi Mick,

http://www.sohc.co.uk/index.php/topic,6985.msg39684.html#msg39684

Within this post open up the Internet reference & you'll see a number of 'recommended' ways to remove rust. Don't remember cola being one of them though... Tom400 tried it with apparently little success (see link below)

The electrolysis method will ONLY remove rust, and not good material, which is the beauty of it versus (eg) abrasives or some chemicals. If you're implying that a certain amount of rust is needed to stem any leaks (!) then it can only be a (short) matter of time before you're back to square #1 and doing some sort of other major job on it. How's about a full rust removal, and then lining the tank with eg POR 15, which Tom400 has fully detailed elsewhere here....

http://www.sohc.co.uk/index.php/topic,4758.msg21866.html#msg21866

Yes, POR in tanks is not for some, but perhaps you have little option?

Simon

PS: Electrolysis is cheap too... only 3 tablespoons of the wife's baking soda.. And if I was to do it again I'd rig something better / more surface area than an old crushed can... thinking a steel ruler (raid the kids school bags...)
Title: Re: de rust a petrol tank
Post by: AshimotoK0 on September 25, 2014, 06:43:21 AM
Wonderful stuff baking soda apart from the tank electrolytic cleaning and blasting uses. Try a little bit with cyanoacrylate adhesive (superglue). It cures up instantly and also 'gap fills' which superglue is normally useless for. My mum once rescued a child with severe burns from falling onto an open fire by treating the burns with a paste of bicarb ( need Nurse Julie to confirm if this is a known method) !

I don't think Coke has sufficient concentration of phosphoric acid to convert the rust quickly. I would try something like this. Diluted of course.

http://www.ebay.co.uk/itm/Phosphoric-Acid-1-Litre-81-48-hour-delivery-Best-Price-on-Ebay-/231316778500?pt=UK_BOI_Medical_Lab_Equipment_Lab_Supplies_ET&hash=item35db8dee04   plus a bag of sharp screws etc to slosh around with it.

On the electrolytic method I saw someone on one of the forums ( probably SOOC) using an electrode made out of a plastic pipe with lots of holes in it and the electrode wire passing down the bore of the tube. That way you never get shorting out of the power supply and ignition of any gases produced . Need to try this method myself sometime on a spare CB250K0 tank I have.

Cheers ... Ash
Title: Re: de rust a petrol tank
Post by: bike-pusher on September 25, 2014, 09:37:51 AM
hairygit - I tried Coke.  Trust me - it doesn't work.
Title: Re: de rust a petrol tank
Post by: Green1 on September 25, 2014, 06:21:13 PM
What would you recommend for a tank with fine rust spots on the tunnel.

Mick
Title: Re: de rust a petrol tank
Post by: mickwinf on September 25, 2014, 10:56:26 PM
Thanks for all the replys but now more confused about what to do, I have a rusty bolt soaking in vinegar to see how it works!
Title: Re: de rust a petrol tank
Post by: AshimotoK0 on September 26, 2014, 12:14:00 AM
Thanks for all the replys but now more confused about what to do, I have a rusty bolt soaking in vinegar to see how it works!

Use either proper concentration of phosphoric acid (see my earlier eBay link)  ( this is often supplied along with tank lining kits). Not Coke , as it's not strong enough. Or use the electrolysis method. Neither will remove good metal and if its the rust that's preventing a leak then it's a leak waiting to happen after an expensive (or time consuming) paint job. 

See this link for electrolytic cleaning,

http://cb750sandcastonly.com/smf_forum/index.php?topic=1323.0


Cheers ... Ash
Title: Re: de rust a petrol tank
Post by: bike-pusher on September 26, 2014, 09:40:46 AM
Not Coke , as it's not strong enough.

As I discovered  >:(   That said, I did use 13 litres of Lidl cola, rather than The Real Thing (sic).....

So what we need is a scientific test of the leading colas on the market, to determine which (if any) works best...
Title: Re: de rust a petrol tank
Post by: tom400f on September 26, 2014, 09:55:16 AM
I tried Tesco own brand. And diet, not with sugar.

But it didn't work so...
Title: Re: de rust a petrol tank
Post by: Nurse Julie on September 26, 2014, 01:57:20 PM
Hi All
Yes to Soda Bic for Ash's Mum's remedy for burns. Good old fshioned remedy but not allowed as a treatment now due to Health and Safety and COSHH regs.It works by taking the heat out of the burns. Don't know if it would work on a rusty tank but Caustic Soda works well on my old sink pipes, so should work well on the inside of a tank. (just make sure you wear a mask and gloves as very caustic and fumes get right in your lungs) :-\

Nurse Julie
Title: Re: de rust a petrol tank
Post by: AshimotoK0 on September 26, 2014, 04:24:34 PM
Hi All
Yes to Soda Bic for Ash's Mum's remedy for burns. Good old fshioned remedy but not allowed as a treatment now due to Health and Safety and COSHH regs.It works by taking the heat out of the burns. Don't know if it would work on a rusty tank but Caustic Soda works well on my old sink pipes, so should work well on the inside of a tank. (just make sure you wear a mask and gloves as very caustic and fumes get right in your lungs) :-\

Nurse Julie

Sounds like she was correct in her prompt actions then. Sadly passed away when I was 17 to bigC  :'(  . Never wanted me to have a bike said they were death traps but thought scooters were OK.  ::)  I am not sure about caustic soda for tank though Julie, I think you need something acidic or electrlytic. Heard of people using molasses too though.

Cheers ..  Ash ...  Welcome back BTW we need more gals on here!
Title: Re: de rust a petrol tank
Post by: Nurse Julie on September 26, 2014, 05:43:42 PM
Hi Ash
There is a really good article in Real Classic Bike Mag  about de rusting petrol tanks, they suggest Caustic Soda and Spirits of Salts.Really good article with all the instructions on how to do it etc
Hopefully this link will take you there
www.realclassic.co.uk › Tech › Insider Info

Nurse Julie
Title: Re: de rust a petrol tank
Post by: Nurse Julie on September 26, 2014, 05:47:01 PM
OOps, that link probably won't take you there, try this one instead
http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=4&cad=rja&uact=8&ved=0CDkQFjAD&url=http%3A%2F%2Fwww.realclassic.co.uk%2Ftechfiles%2Fpetrol_tank_cleaning_and_rust_removal.html&ei=AZYlVLHELuHg7QaZmoDwDQ&usg=AFQjCNGGMi_nGGEIVjflu4uzqR39N7QniA
Title: Re: de rust a petrol tank
Post by: mickwinf on September 26, 2014, 08:43:49 PM
Julie that's a very interesting article, might try that at weekend, thanks.
Title: Re: de rust a petrol tank
Post by: mickwinf on September 28, 2014, 06:08:19 PM
well I have not had a great day, I removed carbs and gave them a good clean, in fact they were not bad only a little sediment in the bowls, gave all the jets etc a clean with carb cleaner and blew them out with compressed air. Put them back on and started up but still not right it is spitting back through the carbs, then set fire to the airbox! All four cyls are firing and all exhausts are hot (know this as I burnt my arm on one!) The only thing I did before these symptoms was adjust the valve clearances so I checked them to make sure all had some play, I couldn't do them properly as the engine was warm but all seemed to have a little free play. Any advice gladly received!
Title: Re: de rust a petrol tank
Post by: kent400 on September 28, 2014, 10:31:56 PM
Sounds like the ignition timing is too far advanced or the advance and retard mechanism is is faulty. The spark is occurring before the inlet valve has closed hence the air fuel mixture is igniting in the inlet track and the air box. Timing must be the first thing to check, although an inlet valve not closing due to incorrect valve clearance is another possible cause.
 
Title: Re: de rust a petrol tank
Post by: mickwinf on September 28, 2014, 10:42:44 PM
timing is spot on and a/r unit works fine, it happened suddenly so the valve clearance is suspect, will check again.
Title: Re: de rust a petrol tank
Post by: AshimotoK0 on September 29, 2014, 08:21:47 AM
Julie that's a very interesting article, might try that at weekend, thanks.

+1 from me good article Julie

Cheers ... AshD
Title: Re: de rust a petrol tank
Post by: mickwinf on September 29, 2014, 07:20:41 PM
well I have sorted it out and a strange one it turned out to be. I checked the valves, nothing obvious there, so decided to re-check points and timing. The 1/4 points were fine and timing exact, but when I put my test lamp on the 3/4 points I couldn't get it to light up at all despite all wiring being ok. so I removed the points and discovered that the back surface where they fit to the backplate was not flat so the points were rocking and not opening properly. They were new items but Diatchi brand,so I replaced them with some old tec items and success!! Points now in bin!
Title: Re: de rust a petrol tank
Post by: Green1 on September 29, 2014, 07:22:21 PM
Que Bitsa  ;)

Mick