day eight!!!

my friend jason hooked me up with this paughco mustang tank. the tank sat really high on the backbone and was at a really steep angle, so i decided to cut out the tunnel and drop the tank down a bit. i also opted to do a frisco style petcock that way i get the most mileage out of the fuel in the tank

in this pic the new tunnel is all welded in, you can see by the discolorization from the welder that i welded the tunnel in with 3/4 in welds. you want to weld with short cool welds and jump around all over the tank or you are going to wind up with a warped tank.

so here all the welds have been ground and i have the frisco style petcock bung welded in. when weldinging in the petcock bung i used sil-bronz rod so that it flows in the gaps better making for a better seal and lower heat to reduce the possability of melting the 1/4 npt threads in the bung. i machined some blind 5/16 x 18 bungs that i welded in the tunnel for mounting the tank to the back bone.

here is my good friend jeff hepworth drilling the holes in the backbone to mount the tank bungs. jeff whipped up som bungs by taking some 5/8 4130 tubing and welding on caps he cut out of 1/8 in strap with a 3/8 in hole drilled in the center these will get welded into the backbone and the fasteners will hide in the bung and retain the tank.

this is how it looks with the holes drilled and deburred.

jeff and i bolted the backbone bungs to the tank then dropped the tank on the bike. after making sure the tank is sitting on straight i placed a few sturdy tacks on the mounting bungs. remove the tanks making sure not to bump your parts out of alignment and weld it up solid

day seven

for the seat i took a piece of cardboard and made this template i test fit it a bunch of times and bend it into the arc i thought i wanted to end up with.

when i got my pattern close to what i was looking for i drew a centerline down the cardboard and cut the pattern in two halves. when i had my half pattern i then layed it on this piece of scrap 1/8 in steel, my scrap was painted already so i scribed a centerline and placed the half patern on the centerline. scribe the pattern then flip the pattern to the opposing side making for a symetrical seat pan. i would go back over your scribed lines with a french curve and circle template to make sure everything gets cut out smoothly.
here the seat sits on the frame in mockup mode, i dont have a slip roller so i bent the shape into this by hand. first i clamped the pan in the vise at the back of the seat and slowly bent a very slight arc, then i released the vise and slipped the pan down about 3/4in and repeated the bending motion, i did this about 5 more times to create the front to back bend. for the bend on the sides what i did was clamped the pan on the centerline in the vice, then i got a large cresent wrench and clamped it down on the side. with it as deep in the throught as possible i slightly bend the pan in the desired direction then move lateraly about 3/4in work slow and you will end up with smooth bends.

here it is witht he spring mounts welded to the frame and the springs bolted to the seat pan. i ended up tacking the bolts to the pan so that after upholstery you wont have to use a screw driver to tighten the fastener.

this bike is going to be running a jockey shift so here is what i whideled up, i just cut off the stock foot shift and used the splined boss to attatch too.
here is the first test run, the riding position is actualy really comfortable, i was originaly planning on running some drag bars but these stockers are kinda growing on me so i think i am going to roll with these. i cut 1.25in off each side to get a little skinnyer look.

day six

on the chain stays you are going to want to make some solid slugs and rosete weld them in the joint where the chain stay hooks to the original lower frame rail.

here the new hard tail section is getting welded on, make sure to jump around allowing the heat to disapate so you reduce warpage of the frame.

in this shot i have the frame welded and am starting to think about where i want to put my tank and rear fender. i am actualy just going to use the stock front fender with a few modifications.

i am planning on ditching the tach, ignition switch, turnsignal indicators etc. so here is a mount i have come up with to locate the speedo. it is made out of .090 6061 aluminum sheet.

here it is cut out prior to bending it, i placed a slight bend in the mount to kick the speedo up so that it is easyer to read, maybe 30 degrees or so.

here it is mounted on the bars.

day five.

here i am building a mounting jig to locate the pangea speed axle plates on my table. i have measured out the axle height on the centerline of the axle and the center of the slot. i also spaced the plates to accept the hub with out needing to machine new spacers. i tacked the entire jig before welding anything fully to reduce warpage of the jig.

this is what the jig looks like when its fastened to the table. i marked the centerling of the jig and measured 100 times to make sure its was square.

grind off all the extra metal from where the previous frame points had connected. i used a big 3in grinder to knock them down then 24g, 50g, scotch brite roloc discs and a single cut file tofinish the areas.

this is just a basic tube bender that can be purchased at harbor freight. i measured the bend angles with an angle finder then bent the tubes as close as possible to where i needed them to be.

figure out your seat stay width based on your measurment you used for your axle plate location. (make sure your chain and sprocket are going to clear the seat stay)

figuring out how to cutout the slot for the axle plate was a bit of a trick. what i did was clamp the bent portion of the tube in a vice with 2x4's the 2x4's allow the tube to sit in the vice square. once you have the tube squared up you and use a block on the side of the tube to measure off to determine the centerline of the tube. this all might sound like a big hassle but it really helps you get the relationship between the axle plate slot and the bend clocked in the propper relationship.

here are the seat stays resting roughly in there new place called home. always make sure to test fit stuff you can really avoid some head aches that way.

another test fit with the slots and tube caps welded on, for the tube caps i just used some 1/8 in strap, cut it with a band saw, weld, and grind her smooth

another view of the tube end test fit.

day four

after determining the desired ground clearance i came up with this jig that will hold the frame at that height, this willbe welded to the frame and screwed on to the table top. if you have a metal table just tack some posts to the table and that will do

draw a centerline down the middle of your table the find the center of your jig and mark it with a sharpie. slide the stand under the bike and make sure the bike is centered over the jig. at this point come up with some way to lock the front wheel in place centered on the table.

make sure you have everything square and straight then tack the frame to the jig. make sure you do some pretty hefty tacks because you are going to be joncing, hammering, beating on the bike and you dont want it to move.

day three

here is a shot of the bike getting stripped down, i am going to leave the engine in so that when i cut the frame the engine mounts wont move anywhere. i am also leaving the front end on the bike to aid in keeping everything straight and square.

in this shot i have the bike up on my bike table, at this point i went through and documented all the dimensions ie: wheel base, axle height, ground clearance, handlebar height. i just have the bike sitting on blocks right now since i have yet to determine exactly what my ideal ground clearance is

right here i am starting to cut the rear section of the frame off keep in mind if you have the engine removed at this point you need to build a jig to keep all the frame tubes in location or as soon as you start cutting you run the risk of warping and twisting resulting in allot of head aches down the road.

cut the frame long so that you can later scribe and grind your tubes nice and square that way everything will fit up right. i using a jig saw with a fine tooth blade, if you have a tight area a cut off wheel works well too.

this is what it looks like with the rear section of the frame cut off, as you can see i still just have it sitting on the wood blocks at this point i will start making decisions about how i want the bike to sit when its all finished.

day two

i got bored after riding it around stock for a few days so i flipped the bars upside down and slapped together some drop struts for the rear. the struts lowered the rear 3in and allowed me to see how the bike was going to ride as a hard tail.

day one..

so here is a photo of my latest purchase. i picked up this 83 xs650 about a month ago i just couldnt resist buying it, i got it for $600 with only 7,XXX original miles. she seems to run great, pulls pretty hard actualy for a 650. so i am going to build her up into a little bobber and will be documenting the process on this blog.