OCC Chopper Bike Build

I've started work on my new build, an OCC Chopper bike I found in a dirty garage. I've already spent several hours on my projectt and I don't even have a kit!

These things are not perfect for motorizing, as the engine has to be kicked left with the end result being the right rear engine mount stud is close to center of the frame. I could have dropped $40 for a pre-fabbed motormount but I simply don't have an extra penny to spend on this. I've created by own by measuring carefully and drilling holes in thick metal. It's a system of transition plate and muffler mounts that I've used before.

The saddle was trashed! I found some material and worked up a new cover with some homemade rivets. It wil work for a while!

The V-brakes, front and back, are good but the headset cap is trashed. I have to rig up some kind of fix to get a tight setting on the headset.

The handlebars are just weird an I don't want to use them. I'll find a simple straight bar as that will maximize function. In traffic you want narrow bars to sneak through tight spaces.

I patched the rear tube but I cannot inflate the sketchy tire because my floor pump failed. My frame pump that I carry for my push bike commutes to work has mysteriously disappeared from my backpack. It doesn't reay matter though because I bought a very cheap motorcycle tire on ebay as I am told they will fit on the fat rear rim. But, boy, this thing cannot be mounted like a bicycle tire. I am going to have to spend $20 for a motorcyce inner tube and maybe buy a few tire tools. There are some hacks on youtube - not sure how I will settle this. If I use the moto tire I will use a 40 tooth sprocket. If I have to default to the 20" bicycle tire, then it will be 36 tooth. At any rate, there's a lot of work ahead for me before this thing yanks me down the road!

Here are some pics:

 

[KCvale]

I am more of a grinder than a welder.

Me too ;-}

 

[Timbone]

I thought some may find the pics of my old jackshaft axle interesting:

This is a stainless steel axle, 1/2" diameter, with grooves scored out for keys. You can see the scored lines that held the e-clips for the two bearings. This jackshaft held two sprockets side by side for the drive sprocket on the back wheel. The other side held the drum brake locked to the shaft with a key.

Two interesting things to note: you can see the extreme forces placed on the axle into the key slot. At first it was a 1/8" key but after it failed I ground out the slot for a 3/16" key. A lot of deformity there!

In the bottom pic, you can see the remnants of the key that held the outer sprocket (final drive chain left side) fast to that shaft.

As I said in another post, I replaced this shaft with a black iron shaft and all the pieces are now welded.

 

[KCvale]

I replaced this shaft with a black iron shaft and all the pieces are now welded.

That is going to make adjustments and replacement parts tough, but I got to figure by the time that needs replacing again so does the frame ;-}

 

[Timbone]

That is going to make adjustments and replacement parts tough, but I got to figure by the time that needs replacing again so does the frame ;-}

It's really not an issue. There's no need for adjustment of any sort now. And to remove the assembly from the bracket I'd just have to cut off the drum brake.

This should endure until I make progress on my dual suspension swing arm bike!

 

[KCvale]

This should endure until I make progress on my dual suspension swing arm bike!

Soft Tails are nice.

You pretty much have no choice but to jackshaft them.

 

[Timbone]

Soft Tails are nice.

You pretty much have no choice but to jackshaft them.

That's the Next Next Level!

 

[Timbone]

OCC Chopper Bike Build Update:

Using FluxCore Wire, I welded up an expansion chamber using the designs offered by Jaguar. I chose the straight version with the centered stinger baffle with the entire assembly being a tad over 35" long. There are 16.5" of pipe, measured from the center, that runs from the exhaust manifold to the first cone.

I used 22 gauge metal which was very hard at first. But as I progressed with the project my techniques for working the thin metal improved substantially. Still there was lots of spatter and a lot of time stitching up small gaps and holes. I fretted because there are two or three pinholes that I couldn't track down. That doesn't matter at all. The pipe isn't quiet, but it's no worse than the stock pipe I was using. (The guts had fallen out and I had to stuff it with steel wool.)

I took a few liberties with the design. I offset the first 3 conic sections so that I could cheat the pipe under the frame, inside the crank, over the kickstand and, a little farther down, kick out away from the rear tire. I don't think a perfectly straight pipe would have worked where I wanted it.

I used 1/2" EMT galvanized conduit to use as my stinger and as the rounded pipe connection between my sawed off stock muffler and the JagPipe. The conduit was a bit too large to fit thru the last cone so I used a cutting wheel to split the stinger and ground off enough material to make proper diameter and - after tapping the tube back to a smaller tube - welded the seam. EMT tubing is really good for welding; it takes heat very well. And so easy to bend. I took the pipe bending tool from the hardware stool display and very carefully bent it to the curve I thought I needed, over 90 degrees. Piece of cake!

All the noise comes out the back now, and it is awesome. Kinda sounds like a Motocross bike. I've only ridden a few miles so far, but the low end is much improved. I can now "Flintstone It": with the engine off, move the bike forward with some foot scampering, pop the clutch and go! No lugging with a 40T on the back!

I took two long high RPM zips up the road and I doubt if it's any faster. This bike is fast anyway, with cruise at 30-33 mph. With a tailwind on the flats it probably will hit 38. I haven't lost anything, though! Good runs! And I like that the traffic behind me gets the best of my exhaust note.

Almost all the weight of the pipe is supported by 4 support straps tied to the frame. All the exhaust studs need to do is hold the pipe flange to the manifold. A whole lot less to go wrong!

I really need to thank Jaguar for the free design. What a gift! My cost was $20 for sheet metal - and I still have plenty left. Best of all, this gives us all the chance to learn and improve our bikes with an enormous sense of accomplishment. How do you put a price on that?

Thanks also to Wags, Frank and others for their advice and interest in this project. All of it helped. There's no way I could do this without this forum! Thanks to all of you!

 

[Timbone]

Today I trashed the OCC Chopper frame. I hadn't ridden on it since August - the rear triangle was too far out of square and it wasn't until today that I figured out why.

I had a major break of the left rear chainstay. I used several pieces of flat stock to encircle the broken area and solidify the chainstay.

Slowly, the rear wheel developed a tilt of center. Since I removed the motor, I got it out in the Sun for a thorough inspection. The real damage was low in the seat tube where my muffler clamp grabbed onto my homemade motor mount. It never broke, but it was collapsing and it knocked the whole frame out of whack. I maybe could have fixed it by cutting and welding in some new parts but I am far beyond that now.

I salvaged the front forks (maybe I'll fab up my own triple tree) and the beefy horizontal dropouts. The handlebars could be handy, too - there's a curved section that I could weld into my exhaust to fit up my Jag inspired expansion chamber.

It was a cool motorbike, and it helped me perfect my jackshaft design. I salvagedthe bearings and I think I'll use them in my rear wheel rebuild.

On to new things...

 

[CrazyDan]

Poor chopper ...whatcha thinking about tossing all them parts on now?

 

[Timbone]

I have to perfect my current bike before I move on to another project. I'll be itching to do something in the spring!

Interesting: today was garbage day so I took the carcass of the OCC frame out to the curb last nite. No saddle. No wheels. No front fork. No handlebars. Somebody took it before dawn!

Wonder if they noticed the rear dropout have been cut off?