FF: Forks How Much Space Do You Have Between FF3 (Bottom Link) and Gas Tank?

[CarlHungness]

I am a bit lost on the original question
1/4 clearance?
View attachment 53262

I'll get a photo. I am talking about up top, on top of the tank where the upper link almost hits the fuel tank, especially when on the side stand. What a nice clear photo you've posted, but you're looking at the bottom of the tank, look at the top, where the link just clears the tank.

 

[timetraveller]

All the larger tanks I have seen, where they have a raised top, have a lower piece at the front in order to provide clearance when the handlebars are over to one side or the other

 

[Bill Thomas]

I have one that touches.
The eccentrics, Standard.

And the Special big tank, Brother Ron built , He bashed 2 recesses in the top .

 

[vibrac]

From the top NB see how low the oil cap is to the tank surface I doubt a standard steel tank is so high and there is still lots of room
NB we have found another advantage to the JE front end it makes a fine catch tank for the few drips of R that squeeze out when the oil is extra hot

 

[Chris Launders]

Hi Carl, I see where you mean, the top link when on full lock.
Yes mine's the same, about 1/4" but at no time would it get any closer, the link moves up with travel and even at fullest extent down the "arm" won't come near the tank.

 

[davidd]

Carl,

You can certainly use aluminum, if the tank is well designed, but Vincent did not use aluminum. If you look at the underside of a Vincent tank it is extremely complicated when compared to other tanks. When Vincent had the large tank made for Gunga Din they supplied a badly damaged tank from which the tank builder could cut the bottom. The new tank would be built from the stock bottom.

I will have to check the thickness.

The metal is here:

A1008 AKDQ | Cold Rolled Carbon Sheet | ASTM A1008 Drawing Type Steel

Aluminum killed drawing quality steel from Alro Steel is a high strength, low alloy steel that has excellent formability, surface texture, and flatness. It is also noted for its uniformity and consistent performance. It is used for appliances, exterior automotive components, shelving, and more...

www.alro.com

I could not spend the time making a fancy buck, so I made a foam buck out of urethane foam, which I glued together with a very thin layer of polyester resin. Polyester does not melt urethane. I used an electric carving knife to shape the buck. When the buck was done I coated it with polyester. I would shape the metal piece to fit the buck.

I lined the sections on the buck and cut steel parts to fit. It meant a lot of pieces and more welding, but the parts were quick to make and did not involve deep drafts.

All the parts.

The bottom is one piece.

The bottom welded in.

Tank mounted for Daytona practice. I gave myself a week to build it and I had 80 hours invested from start to finish.

David

 

[CarlHungness]

Su

Carl,

You can certainly use aluminum, if the tank is well designed, but Vincent did not use aluminum. If you look at the underside of a Vincent tank it is extremely complicated when compared to other tanks. When Vincent had the large tank made for Gunga Din they supplied a badly damaged tank from which the tank builder could cut the bottom. The new tank would be built from the stock bottom.

I will have to check the thickness.

The metal is here:

A1008 AKDQ | Cold Rolled Carbon Sheet | ASTM A1008 Drawing Type Steel

Aluminum killed drawing quality steel from Alro Steel is a high strength, low alloy steel that has excellent formability, surface texture, and flatness. It is also noted for its uniformity and consistent performance. It is used for appliances, exterior automotive components, shelving, and more...

www.alro.com

I could not spend the time making a fancy buck, so I made a foam buck out of urethane foam, which I glued together with a very thin layer of polyester resin. Polyester does not melt urethane. I used an electric carving knife to shape the buck. When the buck was done I coated it with polyester. I would shape the metal piece to fit the buck.

View attachment 53265

I lined the sections on the buck and cut steel parts to fit. It meant a lot of pieces and more welding, but the parts were quick to make and did not involve deep drafts.

View attachment 53266

All the parts.

View attachment 53267View attachment 53268

The bottom is one piece.
View attachment 53269

The bottom welded in.

View attachment 53270

Tank mounted for Daytona practice. I gave myself a week to build it and I had 80 hours invested from start to finish.

David

Superb job, and you have some nice compound curves. Was it TIG welded together? Eighty hours can produce a lot of craftsmanship if one sticks with it, and you sure did. I like the buck very much too. Actually I could probably use the original tank as a buck. I'm just after the experience of trying to make compound curves with a shot bag and stump. I've never formed any aluminum or steel in such a fashion so have a steep learning curve. Great work and thanks so much for the photos, it's easy to see your step by step method.

 

[CarlHungness]

One more question: What guage did you use?

 

[vibrac]

Do make sure you allow for good separation between engine frame and tank since while steel is more tolerant aluminium tanks soon develop leaks if they are not absolutely isolated by rubber and most important take care with the positioning of the under side tags at the rear they have limited location to miss the UFM and engine with the tie rod but are essential to the integrity of the tank.

 

[davidd]

I forgot to check the gauge. I used a thick towel between the shot bag and the steel piece because I did not want to cut the leather on the shot bag. I also used an English wheel on the rear hump on the tank as you can see from the shine.

I TIG weld mostly. I have a Henrob, which is a low-pressure welding setup. It works well for acetylene welding aluminum, but the torch is a little heavy for my taste. TIG is a bit more comfortable.

I mounted foam on the UFM and held the tank on with a strap. I anticipated making an aluminum tank but scrapped the idea of a full-size tank because the system was too heavy for racing, mostly because the tank held too much fuel.

David