my 1981 xj650 true hardtail project

well i just found this forum and i have sort of a build log forum on another site, so i figured i'll post here since it's more relative. Seems like a pretty cool forum, nice to see a bunch of xj fans.

I just scored an 81 yamaha xj650 for $100 which i'm planning on converting into a bobber.
The bike had a bad motor, but it came with a new one which i just swapped in and got running before chopping her up. Once i determined it ran good enough to bother with, i started chopping up the frame. I got the whole subframe section cut off, along with some various brackets and lugs which i wasnt going to reuse. Then i fabbed up my hardtail, chopped the neck, and the last pics are as she sits right now.
I have a full machine shop in my garage with some cnc machines so i can take it as far as i want to.
Any and all ideas/comments appreciated!
Here's where she started (well, it started as a complete bike, but i forgot the pics!)




Here's a few shots of the seat i made for her.


Here's a pic of it partially sanded. I sanded in ass indentations do it'll be a little more "form fitting". It also is a little higher in the rear to keep me from sliding back.


first coat of stain. I did a couple coats and did some more "antiqueing" with a sharpie and some scotchbrite pads. I also got my hands really dirty and rubbed in some crud in some strategic places.



Here's the piece the wood will get mounted to. It's a 1/8" thick piece of stainless. The front pivot is made of titanium. Dont ask why, i just didnt have any stainless round stock so i used what i had. The red pieces are spring retainers i made out of aluminum then anodized red. You can see two mounting the springs to the plate, and the two sitting on the plate are to mount the springs to the spring pertches on the frame when it gets to that point. I wanted this whole assembly to be fairly sturdy so in case i hit a bump really hard or jump a curb to avoid something and the wood cracks, i'll still have a seat under me to keep my ass from sitting on the tire.







I did some cutting, bending, and welding and now my hardtail is getting close to being finished. I started off by welding on the upper half when the swingarm and wheel were still in place so i could maintain proper alignment. Then i chopped off the swingarm and bent up and welded the lower half. The last pic is of my crappy mig weld:cheers: I also raked it out a bit by taking a sliver out of the neck.

 

Here is the dropouts i made, they're 3/8" thick steel. I just surface ground them to take off the scale.. it was faster than sanding. I slotted them for if and when i go with a chain drive. That comes after i find a freebie or really cheap motor. I temporarily welded them in, but i'm going to reweld them with my buddy's welder since i dont think welding 3/8" plate with a 90A welder is the best idea.
I need to machine up a new axle, which is no biggie. I only have the existing axle going through one dropout because it wasnt long enough, so it is sagging a hair in the pics, but when it's all supported, it does look spot on and everything measures good. The gear box or whatever you want to call it attached to the wheel for the shaft drive required a rather wide hardtail. It will allow for a really wide rear tire once i do go chain drive, which will be nice. The shaft is in the way of a bigger tire at this point.
It was exciting getting it on two wheels again. I was looking forward to seeing how it sat. It's right at where i had planned, 6" off the ground (when the rear tire isnt flat).
Opinions/ideas? (although it seems like i'm talking to myself in here lol)

 

I got a new driveshaft off of ebay and cut it and my old one then made a press fit sleve then welded them together. Runs really true between centers so i think it'll be good.
Also, i modified the stock swingarm to make a tube to conseal the driveshaft and also keep the hub from rotating (thanks for the idea Henry).
It was a little bit of an ordeal since it was all stamped and welded sheetmetal, but it came out ok. I bought some 2" dia .12" wall tubing and grafted a 4 inch piece in. Then i did a little massaging, welding, and grinding to get it to conform to the looks of the rest of the tube. Came decent considering what i had to work with.
After that was lengthened, i patched up the hole where the swingarm pivot bearing went, and machined out a mounting plate so i could bolt it to the frame to keep the hub from spinning and killing me.
Then i just powdercoated it and assembled it. The motor in there is the old motor and i took the head and cyls off to make it easier to test fit in the frame.
Assembly went pretty smooth, and i think it was actually a bit easier than dealing with the stock setup, and even easier than a chain for that matter. I was even able to use the stock rubber piece to keep the universal joint clean.






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right on dude. looks pretty good

 

I am very impressed by this. NICE real nice.. I will be watchig and can't wait for more pictures.

 

Man that's some serious fab skills I wish I had. Great build so far - keep us posted.

 

I was thinking the same thing. When I saw he stretch the fram I got excited to see how he was going to get around the shaft... The shafts cover and shaft its self look SWEET. Clean, He has skillz.

 

Good job, real nice work.
Me thinks that seat will get a bit hard on the a$$ on long rides. :lol:

 

thanks guys!
sadly it isnt me that has skills, it's the tools
as for the seat, it's more comfortable than you would think. and i wont be doing much for mileage, it's just for shooting around town.

another update...
i finished powdercoating my forward controls so i threw one on to snap some pics.
The threaded rod is just temporary, once i get them set where i like them i'll make up something a little cleaner. I shortened the old shifter and added a rod end on there as you can see in the pic.
They're a little lower than other forward controls for the xj that i've seen on the market, and these are a little beefier too. machined a dog bone in there while i was at it for shits and giggles... in tribute to my doggies.

 

I wish I had the skills to do that. I love those forward controls. I plan on hardtailing my 550 just like that. Just gotta sell off some more parts to be able to get what I need. I can't wait to see yours finished. Lookin great so far.

How many inches did you stretch the frame? How many degrees of rake did you go for?

 

Saw this build on thechopperunderground nice job. Could this be the guy who brings the world the xj shafty weld on hardtail kit.

 

You say it's "the machines", you are the one making them do what you want. You do GOOD work! Nice job so far. Might need to put some sandpaper on that seat if it's as slippery as it looks :lol: ...

skillet

 

Nice looking work.

Now do you live close enough to me that these "machines" can do some work for me?

 

Thanks alot!
The frame is stretched 4 inches in the rear, and the rake is 38 degrees

 

thanks!
i dont know if i want to do any more, one was enough for me lol

 

thanks!
i'm in San Diego, CA. a bit of a drive!

 

hey man... just wondering how you cut out the slots in your frame to fit the axle plate?

 

I like the dog bone lightening hole on the shifter nice touch. Was wondering if it might be better to flip shifter on engine end to reverse shifting.

 

glad you came over bro. I knew you'd get lots of questions, you're doing revolutionary stuff no one here has done

 

i did that in the milling machine before i welded them in

 

thanks!
as for the shifting, i always had gp style shifting on my sport bikes so i'm kinda used to it.

 

yea, thanks for the heads up on the site man, lots of good info over here.
As for revolutionary, i dont know, i'm sure it's been done before

 

i see i see.. i only wish i had the tools to create like you do... i just tore apart my bike and i'm planning on doing a hardtail but mine's the 400 so it's got a different frame.. a little challenging.. but i'm hoping on creating something amazing even though i have no fabricating experience... just time and patients... if you've got any pointers for me my build is artie's 82 xj bobber project...

i'll be following your build and hopefully picking some things up here and there from what you've done... keep up the good work.. can't wait to see the final product!..even though the building is the reward, being complete is a bonus haha..

 

yea, i checked out your build, it's coming along nice!
might want to consider buying a hardtail kit, they're only about 100 on ebay and it will make life alot easier.
As for fabricating experience, it's not needed as long as you're willing to deal with the trial and error. ive seen some total noobs build some nice stuff!


Got a little work done today. I machined up a pivot/lever do-hicky for the rear brake. There wasnt a straight shot to the drum from the forward controls, so i needed something. It also converts the forward control from "push" to "pull", which is what the drum brake needed. The lever itself is aluminum, and i made a 2 piece bushing out of 4140 alloy steel then powdercoated them. I anodized the aluminum lever red, and i also anodized the aluminum parts of the forward controls, then i remachined the surface to give them a different look. They look better in person, the flash made them look weird.
I still gotta make up some fancier rods to replace the all-thread, but that can wait. They function as is.

 

Nice work. Definitely NOT a cookie-cutter bike going on here. Looks good.

 

I think you have been a bit modest about your skillZz. This bikes going to look really good I think..

 

nice, what kind of mill and software are you using?
i never got the hang of anodize so i just go with gun kote, you seem to have it down

 

Looks real nice, I know what you mean about the threaded rod, it gives a little doesn't it. I'm replacing mine with 3/8 inch square rod with milled ends and threaded.

 

thanks guys!
i'm trying to not go cookie cutter, but it's all been done, so that's hard to do.
As for my mill, i have a shizuoka an-s cnc mill with a homemade controller using EMC2 software, along with a manual mill. The software i use is solidworks and mastercam.
Anodizing can be tricky, took me a while to get it down. Still not perfect, but usually acceptable.


as for the threaded rod, yea, it bends a little, but not too bad. I just used it for mock-up purposes so i can get them where i want them, then i'll make a solid rod to replace the all-thread.

as for the bike looking real good when it's done, i can only hope. I can machine stuff ok, but i'm not exactly a style guru. I may need some help from you guys for fender and tank ideas.

 

Here's a place where you can get Stainless Rod.

http://www.alphaknifesupply.com/ss-rod.htm

Getting the Die Started on Stainless is tricky sometimes.
Grind a light chamfer on the end of the rod.
Having a New Die don't hurt; either. Lots of oil.

 

thanks for the link! probably wont use a die though, i'll just single point it on the lathe.

 

one of the triple trees i'm working on. There's a little more offset in it so the trail will be correct. Looks kinda weird in the pics i guess... i might work on it some more. I thought maybe putting some spikes in the front in the center of each silver square would look a little better.
open to ideas.
It's the standard 3.5" spread for bars/risers so i'll have more of a selection of bars if i dont end up making some. for now i'll probably make some risers for my 7/8" drag bars.
underside


top/front

 

dude you gotta make me some.. pleaaaaaaaaaaase..

 

haha wish i could, but they'd be pretty expensive due to everything involved in design/machining/anodizing

 

so i finished the trees and got them mounted. Not too sure about the squares in front, might machine it smooth. I'm not going to do anything with it at least untill i finish the headlight housing, but i'm pretty sure i'll be changing it. It went together pretty smoothly. much better than the stockers, those things are never too good.

First pic is the stem after modding. drilled and reamed for 4 .1875" dowels and pressed them in and put a dab of weld on each one. It isnt going anywhere. It's also a nice press fit into the lower tree.

 

nice man!.. i agree with the front squares... would look nice smooth.. but very slick indeed.... you've got some talent for sure... i think your bike is gonna be unique and one of a kind for sure!.. keep it up..

 

Good stuff. I think the trees look a little beefy but as stated will look better smoothed out. Maybe punch them through the tops to allow lowering in the front if so desired. Great work all around.

 

thanks guys, i'll probably smooth the front out eventually. They do look a little beefy with no bars or headlight, but i think it'll look better when the bike is fully assembled.
As for punching the holes through the top tree for the fork, i designed it that way intentionally so that's staying. I know i wont be lowering the forks any as i have the rake, ride height, and trail dialed in where i want them.

 

well, i removed the squares. i think it looks better now, and i think it'll look way better once some bars and the headlight are installed.

 

Damn sure lookin' GOOD!!!

skillet

 

Looking really good...can you make me up one of those seats? I am a carpenter, and it would be pretty cool to have wood seat...let me know thanks

 

hey man.. it wouldn't be that hard to make one of those seats... if you're a carpenter, wouldn't it be easy for you to make one yourself... just figured you have the talent... and mounting it wouldn't be that hard either..

 

Great job on the trees, you should start a side line job. Looks like you could have a few orders if the price was right, I'm sure some people would buy them just to be able to change to different style handlebars and risers.

 

Very nice work, and very well done. I love the design.

MN

 

thanks guys!
cafe_bobber_82, i agree with barefoot, might be a hell of alot cheaper for you to make one and you could probably do a better job than me.
I got some hours into that seat, more than i'd care to admit lol.

 

Just curious as to what your plans are for the motor work I see in the pic.

Thanks,

 

that's a junk motor, i just pulled the heads and cyls off so it was easier to lift in and out of the bike while i was test fitting stuff. The good motor is sitting in the corner in one of the pics.

 

Looks alot better without the squares. Nice and clean

 

thanks!


btw, wait till you see what i made today! i think you guys will dig it. pics tomorrow hopefully.

 

doh!