twin petrol tank convershion

[Watfordwhite]

Does anybody still manufacture the twin petrol tank conversion?
I want one for my S2 but want to retain the original look. Any pointers would be great.
Or even a second hand unit???

[hullygully]

try Broady

[Storkfoot]

I took toolbox and tank to a local fabricator. I gave him a couple of drawings too. He welded it all and pressure tested it too. I did enquire how much MB charged before I went down this road.

[Watfordwhite]

I took toolbox and tank to a local fabricator. I gave him a couple of drawings too. He welded it all and pressure tested it too. I did enquire how much MB charged before I went down this road.

Any idea what that was Storkfoot? Just to give me an idea on what I am expected to pay? I know some very good metal guys.

[Warkton Tornado No.1]

Post by Storkfoot » Thu Jan 26, 2017 6:53 pm

I took toolbox and tank to a local fabricator. I gave him a couple of drawings too. He welded it all and pressure tested it too. I did enquire how much MB charged before I went down this road.

Storkfoot has suggested some good advice, but you might be able to buy something ready made.

Your question served to remind me that in the 70's I had a mate weld up the leaky corners of a standard metal toolbox & weld in a piece of sheet metal to make the tank. You could allow a recess to store a few things behind the toolbox door.

Mine differed to the 'norm' of today though, as it was a separate tank. It had a standard tap operated by the choke position lever (the bike ran an Amal Mk I with tickler) & the fuel cap was welded in place on the LH side by virtue of a big dent to act as a recess.

It was in the days when you could afford to sacrifice a perfectly good tank to make such an item...

BTW. It was also the days of 'Guvvo' & cost me a cup of coffee from the work's machine

[Storkfoot]

I took toolbox and tank to a local fabricator. I gave him a couple of drawings too. He welded it all and pressure tested it too. I did enquire how much MB charged before I went down this road.

Any idea what that was Storkfoot? Just to give me an idea on what I am expected to pay? I know some very good metal guys.

I honestly can't remember as it was two or three years ago now. I paid £90 but then I knew the lad who did mine welds stainless tanks for the food industry ( he knows what he is doing).

If you email Mark, he will quote you a price. You can rest assured that he will do a good job and, at the end of the day, the last thing you need is a leaking tank.

One of the Vietnamese companies did a twin tank. I never looked in to that as I wanted to make the welding was well done, for pure safety reasons.

[tim_mason]

A bit off thread , In the early days i had a twin tank but it was a converted air filter box ,

[gaz_powell]

I have 3 of them (all in bikes) done by various people over the years; Gary Simpson did my first one, then I used a local fab shop, then a made did one.

This is public domain and might be useful for the fabricator http://www.mbscooters.co.uk/info/mb-twi ... x+185.html
I would fear to think how much MB would charge to do one these days.

Just measure where you want your tubes welding for the link pipes from a tank and toolbox in a frame - use a big bottom pipe (some I have seen use a small pipe, they will be slow to fill) and keep it as low as possible.

I always mount the link pipes central so the set up can be used with LH or RH big carbs - its a little bit more hassle fitting the link pipes but do-able.

Good Luck

[Storkfoot]

^ yes, come to think of it, I printed these pics and gave them to my fabricator. My connecting pipes are both quite big - 20mm top and bottom. It works without issue so I doubt there is any real need for a smaller diameter top connector.

[Watfordwhite]

Thanks guys, some great advise. Using this system I assume I will need to add 2 stroke first to make sure it mixes when filling up?
I seen the Sigon special on the interweb. I think I will give that a very wide birth.

Any down sides to this, apart from loosing a tool box? Or would I just be better off using the 11ltr standard looking mid range tank?

[Storkfoot]

I have just treated it the same as any other tank but I always put oil in first and then just allow the flow of the petrol from the pump to mix it.

Downsides:

I have never actually had a leak from the pipes held on by the jubilee clips but keep checking the tightness of the clips as they do seem to work a little loose over time.

Fiddly to fit. There's a distinct knack to getting the connecting pipes on and, in my experience, you need to place some rubber around the toolbox part to ensure it is not coming in to contact with the frame and is pushed back sufficiently to allow the toolbox door lock to work. I have used cut up legshield trim.

[Phil D]

Hi
I was Just wondering how much extra fuel the tool box conversion holds?

[gaz_powell]

I use a sticky back rubber and stick it the recess in the frame.
Pipes are hard to fit, I find putting them in boiling water helps.
I've put oil in before and after fuel and never had an issue.
Keep an eye on the fixing bolts on the toolbox part.
I would say you get another 4 to 5 litres - but I find because of where the bottom pipe is some fuel is left in bottom of toolbox.
I like them as they keep the original look, not sure why as no one sees them. When I welded up the toolbox door on my gp it was a pain to fit.
I'll probably fit a big tank on next build

[mark1]

I've had a couple and they work great. You can get about 13 litres in them. I welded them myself.

One thing I would say though, make sure you use 20mm diameter tube for the connecting pipes, anything smaller and it takes forever to wait for the fuel to transfer over when you fill up.

[corrado]

I've got a new set somewhere, I'll have a dig for them. Viet ones but I had the connection pipe made larger to speed up filling time but I never managed to find any suitable petrol resistant pipe big enough diameter [about 20mm from memory]. Even had them powder coated after the welding was done.

[ian i.o.w]

I use twin tanks in 3 of my bikes the connecting pipe a bit small and slow ,but works fine ,it only takes a fraction longer and lets you bike cool down for a bit longer ,never bothered me ,get my connecting pipe from a boat place

[corrado]

Again from memory but I don't think the top connector needs enlarging as fuel doesn't need to flow through it it's just a breather pipe.

[gaz_powell]

I use 20mm on the bottom and I think was 12mm top as said it's just a breather.

I fitted one of that I think was a viet one and the quality was decent, but the pipes where small and on the edge of the kickstart side- I replaced the bottom one with a 20mm pipe in same place and left the top - so it's only good for a LH carb. Good thing about using the outer edge was the pipe was on the bottom of both tank and toolbox, where as my central located ones sit above the frame and leaves some petrol in the bottom of the toolbox (unless I'm going uphill!!!)

[corrado]

where as my central located ones sit above the frame and leaves some petrol in the bottom of the toolbox (unless I'm going uphill!!!)

Bit of a bugger when you run out of fuel and have to lift the front end 6 foot in the air to drain the "hidden" petrol.

[HxPaul]

Does anybody still manufacture the twin petrol tank conversion?
I want one for my S2 but want to retain the original look. Any pointers would be great.
Or even a second hand unit???

One on ebay at the moment.http://www.ebay.co.uk/itm/lambretta-twi ... Sw44BYkPpz