SR500 Name Undecided

[hunter31415]

When I was 20 I bought a basket case 79 Yamaha SR500 for 100$. The motor was in the trunk of a Lincoln Town Car and the carb + lots of extra parts were in a box in the back seat. After about a week and 75$ I had a ugly beater to get around on. Bike had 28kish miles on it when I got it running and put another 4k or so on it before the speedo cable broke and I never got around to fixing it. I rode the bike for another year and a half including wrecking it once (my first roadbike wreck) without spending any of my nonexistent money on it. In the end I got tired of getting wet when it rained and found a broken down honda prelude fixed it up and set the bike in the garage. After a year or two I sold the SR to a friends older brother who rode it around for a couple more years before putting it in his garage. A couple months ago I found myself with the means and the money to build a bike and thought of my old SR, gave a guy a call and that night I had my old bike back for the same price I sold it. Although in worse condition but who cares it has good history to me and its not going to stay in one piece for very long.

Some Pics from the bed of the truck in the dark with a crappy cell phone camera

Friends brother found this dent under 3 pounds of filler. Someone must have dropped it on a trailer at some point.

Took it to the shop and started the fun part, teardown.

Found this awesome wiring under the seat.

And fixed it.

Popped the motor out then started detabing

Picked up the new suspension for the bike from craigslist. 95 GSX-R 750 front and rear end. The Front end slides right in but the rear is gonna take a bit of fab.

Picked up a 80 Suzuki GS NOS tank and modded it to fit around the oil tank.

New rear monoshock swing arm is a inch wider than the original SR swingarm.

Cut off the old Swing arm mounts after using a center punch and a micrometer to take measurements for the new swingarm bolt location.

Cut new pieces to make the new swing arm mount.

And thats how its sitting right now, crammed under my bench at work. Need to finish the swing arm mounts and make upper and lower shock mounts still but progress is progress.

 

[BLSully]

Impressive progress so far. Always cool to see bikes come back to former owners. Good luck w/ the suspension conversion!

 

[smvirili]

hopping on the bandwagon. looks sick

 

[scottyfunj]

Love the front end.

 

[SeekingZero]

Looking good! Love that tank.

 

[Eleganten]

How much "bolt on" was the front end? Thinking of putting a front end off a ZXR400 on my SR but i have none and zero skills in that department...

 

[hunter31415]

https://www.allballsracing.com/index.php/forkconversion

Search your bike and find a doner with the same stem bearings and it isn't bad at all. Trying to mix and match bearings to get a stuff to fit is a nightmare. This chart doesn't have stem length on it so you you still need to do a little research. The forks I have are from a 95 GSX-R 750 only thing I had to do is pop out the old SR ball style stem bearings and put new needle rollers in and it just bolted on. The rear suspension is gonna be nowhere near as easy but it will be worth it.

 

[hunter31415]

So after dickering back and forth on the swing arm while not busy in the shop, finally just went for it. Used some 1.5 inch stock and bored a 31/32 hole in it then honed it to 25mm. The 25mm hole is a very tight fit on the stock GSX-R swing arm bolt. Then bored a 1.5 inch hole in the flat plate welded to frame in place of the stock stamped mounting locations.

The holes in the 1.5 inch stock are bored a bit off center so you twist the stock in the holes in the plate to adjust the square and true and level. This step took about 3 hours of tweeking.

Also had to keep the whole assembly centered to the frame while adjusting the rest of the alignments. The square is strapped to the swing arm on the center line of the tire and there is a mark on the frame on the center line of the frame/downtube.

The point of no return.

Finishing up the welds.

The clearance between the back of the motor and the swing arm is about a mil or two. Bad picture but the camera didn't like the shot.

And finally some shots with the front forks and tank on. I had to use a 5mm spacer under the bottom stem bearing to keep the neck tube from rubbing on the bottom triple tree. other than that it bolts right on using the new allballs tapered roller bearings stem bearings for a sr500. By 5mm spacer I mean i recycled the old ball bearing race that I took out of the frame. The fit on it is a little loose so I will probably make up something different later.

Spent months changing my mind about how to mount the pivot bolt. Still need to trim off the 1.5 inch stock to get rid of the big tubes sticking out each side of the frame. Also need to fab up the tabs for the shock mounts. That will probably take a lot of time with a jack and stool to decide on the ride height.

 

[hunter31415]

 

[SONICJK]

That thing is looking badass
Nice work.

 

[bradwsm]

Cool! What are you plans for the countshaft to rear sprocket alignment? Looks to be a number of inches.

 

[hunter31415]

Cut down a OEM sprocket so I have just a washer with the counter shaft splines, Turn down a piece of tube and weld the shaft washer into it. Turn down a new gsxr sprocket so i have a washer with the gear on the out side weld that to the outside of the other end of the tube, custom chain guard with a bearing pin that supports the bearing that fits inside the end of the sprocket extension, Have to space it out about a inch or so. Nut goes all the way down to the original sprocket then bearing slips in the end up to a machined lip probably C clip it in.

 

[hunter31415]

Got started on the seat today. Going to build a carbon fiber pod and seat combo with a inset ducati tail light that slides down the 1x3 box tube. Tube still needs some lenght taken off. But what ever here is some pictures.

Don't touch the paint can its structural






Diamond for strength wouldnt want the seat falling off while on the road.


Some more reenforcement

Wheel base is ~58 inches up from ~56 inches stock but dang I think it looks tiny with me on it.



To do list for the next while is make the seat/pod, decide if it is going to get fenders or just leave it blank. Need to figure out headlights and the koso gauge and decide if i want a little cowl to hid wiring and stuff behind.

 

[twistekeys]

Looks sick dude. But, if I may. In one of the pictures you show that the only original parts are the main frame and engine remaining on the bike. Why don't you building/buy a frame that fits an awesome engine and go from there? it would be literally just a few hours of extra work with your skills.

 

[VonYinzer]

Awesome project. Definitely following along.

 

[andycafe]

Oohh that is nasty 8) love the mono rear

 

[hunter31415]

Can't really explain why I didn't just build a totally new frame. It kinda goes like this. If I just build a totally new frame then its not even the same bike anymore and I would probably use a different engine too instead of spending hours and hours to squeeze 50+hp out of the single. Then its just a custom bike instead of my first bike. Also this project has been a snowball. The original idea was de-tab, strip everything off, flat track seat and a little motor work. <1000$ and a couple months after work. Then I ran across the GSX-R front end and tossed that on. Then the rear swing-arm sat under my bench taunting me every time I saw it and one day I decided if it would be a crime not just go all the way with it. So now I am more than a year in and the budget is so far gone I don't even care anymore. Danm its gonna be cool though.

 

[twistekeys]

Can't really explain why I didn't just build a totally new frame. It kinda goes like this. If I just build a totally new frame then its not even the same bike anymore and I would probably use a different engine too instead of spending hours and hours to squeeze 50+hp out of the single. Then its just a custom bike instead of my first bike. Also this project has been a snowball. The original idea was de-tab, strip everything off, flat track seat and a little motor work. <1000$ and a couple months after work. Then I ran across the GSX-R front end and tossed that on. Then the rear swing-arm sat under my bench taunting me every time I saw it and one day I decided if it would be a crime not just go all the way with it. So now I am more than a year in and the budget is so far gone I don't even care anymore. Danm its gonna be cool though.

That's how it should be I guess! but you're damn close to being able to just building your own bikes.

 

[hunter31415]

Been tossing around ideas for my next bike. Leaning towards an all aluminum frame tiny cafe racer. I have a KTM 65cc race motor laying around. Super light, noisy, blue smoke bike to ride around town and to work.

 

[Driftunit]

Following!