In this post I will show you how to mount a sprung solo seat using our seat pivot as well as our seat spring perches.

I will start with an aftermarket chassis that is an early reproduction frame with a fender and tank already mounted in place.  I recommend not installing your seat until you know exactly where both the gas tank and rear fender are going to live so you can really see what tis going to look like as well as it’s function, not hitting the fender and chipping the paint when the springs are fully depressed.  Leave a  little extra clearance for the seat pan under full compression , most pans especially those with a lot of cup or arch in them tend to deform back toword the fender under load. 

I am going to be using one of our Front Seat Pivots from www.bungking.com for use as a front pivot for this build.  The pivot has two flanged bronze oilite bushings in the locations where any continued rotation is going to be for extra long life without any wear and built in lubrication.  To lock down the bushings and the center bung the kit comes with stainless shouldered bolts and correct shim washers, the shoulder allows you to tighten the shoulder tightly against the bung to keep the bolt from loosening but allows enough clearance for bind free rotation.  Most people and manufacturers don’t understand how important keeping a tight slop free front pivot is, if the holes or bolts gain extra clearance over time with just springs on the back your seat will flop back and forth every time you shift your weight or take a turn making it worse and worse over time. 

Because all seat pans and chassis are different we do not send the pivot out with a tab with pre drilled holes, this would limit you to your seat location.  Most of us who have a welder have the ability to drill two holes in a piece of flat stock so do so in a location that fits your needs and tack the flat stock to the threaded bung that comes in the kit.

Once it cools off enough to not burn the leather on your new seat bolt the strap to the pan and assemble the front pivot to ge it ready to moch it up in it’s location on the frame.

Once the seat pan is mocked up in its correct location front to back as well as side to  side on the chassis it is time to tack the two tabs to the chassis itself.

With the front pivot located it is time to locate the back of the seat pan, in this case the customer wants to use round or beehive style springs to support the back of the seat.  Most solo seats have bungs welded to the pan to locate the top of the springs, the bungs seen above are our Seat Spring Perches that we offer at www.bungking.com .  The pin will locate the bottom of the spring to the chassis but allow you to quickly raise the seat to allow access to the battery or oil filler cap if needed.  Some manufactures add a horizontal hole in the pin to be able to insert a hitch pin in place, however on paper this looks good as soon as you sit on the seat and the spring compresses 90% of the time the spring will bend the hitch pin in such a way that you will need to use a set of pliers to remove or in worst cases have to cut them out.  If you set them up right a pin is not necessary it is more of a hassle than anything. 

This is the Seat spring perches tacked in place, we offer them on either a 1″ or 1 1/4″ cope dia to fit your needs.  They can be found at http://www.bungking.com/accessories/seat-parts/seat-spring-perch-mount.html.  If you weld the perches with the pins tilted slightly back at an angle this will resist them coming off of the pin when you do not want them too but still allowing you to remove them when needed.

After all of it is tacked into place remove the pan and the springs and fully weld all of the parts to the chassis.

After all of the parts cool to the touch you can install of the parts back in place to check all of there fitment and admire your work.

Not all of the custom bikes we work on are always from Milwaukee, like most anything in the custom industry there are always customers with a wide range of interests.  Some of our customers because of cost, reliability, sentimental value, or many other reasons have a vision of building something out of the ordinary.  In this case we had a customer who wanted to take is V-Star to the next level and turn the chassis into a more 70′s styled chopper by adding more rake, a few more inches in the backbone, and a few more inches of rise in the neck.  All to create that 70′s style rake with that long front end.  To help make the backbone more appealing and give endless options for a gas tank, the backbone was replaced with a single 1 5/8″ tube similar to aftermarket HD chassis. 

I braced up the factory frame before lopping off what was not needed, be sure to brace around all of the motor mounts so the relationships of the holes do not change.   During the original welding process a lot of spring can be created in the chassis and with out bracing simply cutting into the tubes can cause  a large amount of distortion.  After the neck is cut free I cleaned it all up grinding away any remnants of the old tubes or weld beads, and mocked it back up in our jig in the requested location.  You can reuse the stock neck if you can find tubes made by your manufacturer of the correct length or you can always search the HD aftermarket for one that is set up for Harley front forks.  There is usually a lot more aftermarket choices for front ends in the HD market than from the Japanese manufacturers.

After all of the tubes are welded into meet the neck it is time to create a gusset to help support everything.  A little gusset can go a long way to creating strength and stability to your welded assembly. It also helps spread the load of pressure and stress over a larger area thus creating more strength.  It is also important to use a thicker wall tubing for the backbone, especially when running an extended front fork.  A wall thickness of over .187″ is recommended, I have seen many .120″ wall backbones on aftermarket chassis crack completely in half during the big chopper boom in the late 90′s and 2000′s before manufactures started to figure this out.

The customer also wanted to turn back the clock a little bit as well and turn this straight leg frame into a wishbone, so I bent up some tubes to create that look of a wishbone .  All and all this took an ugly chassis with little to no choices for a fuel tank into a very universal chassis that could make you mind wonder with all the options. 

Article By www.Bungking.com