HOW TO MAKE AN OIL TANK - PART 1

I  am going to outline how to make an oil tank for your chopper. I have used 5" heavy truck exhaust. You can usually get this from a local dealer that works on heavy trucks like dump trucks or semi's etc. It is 16 guage mild steel and is easy to weld. If you cant find a local dealer then you can order it online from supply shops like this ( http://store.airflo.com/plsttu5od.html ) or someplace like www.bungking.com, though they are more expensive than a supply house. 

This is gonna be a straight and simple round oil tank that fits under your seat behind your seat post. I have only built 70's SOHC Honda Choppers so I can only attest to what size you need for that bike. I made mine 13" in length in order to flow with the lines of the bike and this suited my capacity needs. But the magic math formula to figure out the volume of a cylinder is at this link, or just google it. 
..http://www.mathsteacher.com.au/year9/ch14_measurement/18_cylinder/cylinder.htm

But basically it's        Volume= Pi (3.14) x radius squared x height
So if my tube is 5" across x 13" long my formula will be
Volume = 3.14 x 6.25 x 13
which comes to 255.125 cubic inches or 4.18 liters. I know by bikes oil capacity is something like 3.7 liters so that will be big enough for my needs.

Step #1 is done. you have aquired your tubing.

Step #2 is figure out the length of tubing needed for your bikes oil capacity and chosen tube radius. For example you can use a bigger diameter tube and go shorter in length to get the same volume.

Step #4 Cut the tubing in a straight line at the desired length

Step #5 Find the center of your tubing from left to right as well as the center from top to bottom and mark the location for the fittings. These will include the oil drain, ouput and return feeds, oil fill, vent, and attachment bungs.

Step #6 Use a unibit to drill the holes that coincides with the proper diamter of the tophat bungs for the fittings.

Step # 7 Cut out the end pieces from 16 guage flat steel you got frokmk your local home depot.

Step #8 Weld in the fittings and the end caps

Step # 9 Weld on the chosen bracketry, ie. threaded bungs for mounting. 

Step # 10  Rattle can that bitch and mount it. If it leaks you suck at welding and bribe a buddy that knows how to weld with some steaks and beer to do it for you.

Step # 11 Ride it into the ground


Those are the basic steps, but really Im gonna cover them more in depth over a couple of posts with photos and such so you can really see whats up.

Step #1

Heres a pic of some 5" exhaust tube I picked up from a friend.
This is about 3 feet long.

 

I know the length I need because of my magic math equation, So I measured it and cut it at 13". Use something you can wrap around the tubing to ensure a straight line when you mark it

I used my cut off wheel to cut along the line I marked. 

In these pictures you see the unibit I used to drill the holes as well as the center line and location marks for the feed and drain. I located my drain on the left side of the bike so that I can use the natural lean of the bike on it's kickstand in order to facilitate draining the oil. On my Honda SOHC my oil lines are on the lower right of the engine so it only makes sense to put them on the right side. Make sure you don't put the holes to close together so you don't have enough room to weld in the tophat bungs without sitting right on top of each other.  

                                                                         Cut Tube

The unibit...super freaking expensive ($50) but worth it. I got the one that goes up to 7/8 ", it pretty much does me right.

Here you can see the center line I measured and the 3 holes I drilled on the bottom for my drain and two feeds.


Ok thats it for this post. Please check back on Sunday when I write up my next installment. Ride on.....