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 had to come to grips with reality and remove the crazy heavy Harley Dunlop tire from the bike.
Realistically, it was too heavy for the little motor. Hell, it was too heavy for me to pedal, really.

Well, you can go the Micargi JAOS 3.0 route if you want a mini Harley Chopper look.

Just to give you an idea of size, here is 6'2 200# man standing by it.

A 3" back tire looks cool if the front tire is only ~1" hehe.
That sucker sure hauled donkeys though, 30+ and the brakes to stop it.
Fun build.

 

[Timbone]

That is a great build, KC. Very clean, as is your strength, and a very good job sourcing a superb base bike for a beautiful end result.

You have an eye for aesthetics, that's for sure. I am probably a bit more simpleminded than you. I prefer wheel symmetry, not really sure why. Just as I much prefer a "naked" motorcycle look in contrast to the more common plastic armor coverage that dominates, equal front and back wheel size appeals to me. I think it makes the bike look serious. I am certain your little front wheel does quite well, though.

That rear fender is perfect and brings out the soft curves of the top tube and downtube. Very good. Looks like fun!

 

[KCvale]

That is a great build, KC.
Very clean, as is your strength, and a very good job sourcing a superb base bike for a beautiful end result.

That rear fender is perfect and brings out the soft curves of the top tube and downtube. Very good. Looks like fun!

Thanks for the kudos ;-}

The customer brought me the bike and asked if I could motorize it.
Yes, I could ;-}

 

[Timbone]

I was having great fun until this happened:

Complete break of what I will the left seat stay. Happened just as I got to work.

This fracture run right into the outside of the weld of that oval top tube. I got out the rig welder and tacked it up. Welded as many tacks as possible, then stitched. I put a piece of sturdy 3/16" mild steel and welded a kind of spine. On the left side, I welded a gusset of steel to connect the seat stay and the chain stay.

That fix lasted about three days if hard riding. I did some hard bouncing on the saddle and got the original welding to break.

This time, I took a great deal of time and examined the break. The spine part I welded was the only solid part of the fix. Strangely, my gusset was solid as well, but it didn't alleviate the stress at the break point.

I took my time and welded as well as I could all the way around the break. Then I ground off the slag and spatter and added another piece of 3/16" mild steel as a wrapper along the back.

I took a short trip around and it felt solid. I also did some very hard flex tests and more bouncing.

I'll probably add a new support piece or two as the weekend progresses.

This is a distraction from my Jag Pipe Project. All cones cut out; first two are welded up and airtight. Number 3 has been tacked and has some stitching.

I'm using 22 gauge cold rolled steel. I have to use minimum heat, mostly tacking and stitching - linger too long fiddling with the puddle and you'll blow a hole.

I don't think flux core is good for any of this. I think I'd see much better results with some shielding gas.

 

[Timbone]

View attachment 77968 I was having great fun until this happened:

Complete break of what I will the left seat stay. Happened just as I got to work.

This fracture run right into the outside of the weld of that oval top tube. I got out the rig welder and tacked it up. Welded as many tacks as possible, then stitched. I put a piece of sturdy 3/16" mild steel and welded a kind of spine. On the left side, I welded a gusset of steel to connect the seat stay and the chain stay.

That fix lasted about three days if hard riding. I did some hard bouncing on the saddle and got the original welding to break.

This time, I took a great deal of time and examined the break. The spine part I welded was the only solid part of the fix. Strangely, my gusset was solid as well, but it didn't alleviate the stress at the break point.

I took my time and welded as well as I could all the way around the break. Then I ground off the slag and spatter and added another piece of 3/16" mild steel as a wrapper along the back.

I took a short trip around and it felt solid. I also did some very hard flex tests and more bouncing.

I'll probably add a new support piece or two as the weekend progresses.

This is a distraction from my Jag Pipe Project. All cones cut out; first two are welded up and airtight. Number 3 has been tacked and has some stitching.

I'm using 22 gauge cold rolled steel. I have to use minimum heat, mostly tacking and stitching - linger too long fiddling with the puddle and you'll blow a hole.

I don't think flux core is good for any of this. I think I'd see much better results with some shielding gas.

Update: despite my distrust, my flux core welding repair is holding, still feeling very solid.

I had another problem crop up:

I use a jack shaft on the rear to kick the drive chain left about one inch. Originally, this was to kick the chain around a very wide motorcycle tire which turned out to be too heavy.

I kept the jackshaft. Reasons why:

1) Gives a good chain line from the motor. Gives a good chain line to the drive sprocket on the left.

2) Short motor drive chain eliminates the need for a chain tensioner.

3) Jackshaft allows to the addition of a jackshaft brake with the drum fitted on the right side of the bike.

All three of the connections to the stainless steel shaft employ slots and keys. Just as I repaired the frame (for now???) I had trouble with my outside (sprocket drive) sprocket losing grip with the shaft. The original key broke.

No prob, right? I got a small stainless steel screw and grounded into a perfectly sized key and hammered it carefully into place. That key lasted about 3 days before disintegrating!

So, today, I went to Lowe's and bought a 3 ft piece of 1/2" steel rod. Not stainless, but the weldable type. I cut the shaft to proper size and scored the shaft in the right places to receive the e-clips for the bearings.

The tube I use to hold the assembly are those fence couplings with 1 1/2" diameter. Very strong! I just allowed the pipe to sit in the bracket, held in by pressure. I ground up the contact points and welded both sides into the bracket.

I had to pay attention to building up the shaft - didn't want to back myself into a corner. Those fence couplings have and indentation in the center and you can't just push the bearing through. I placed the inside e-clip for the brake side bearing and, with the bearing as far away as possible and covered I welded the inside sprocket into place. After grinding was done, I placed the outside sprocket into position and welded the outside. There wasn't enough room to get to the inside. I can't imagine that it's necessary!

I ground off the slag and it all looked decent. I slide the sprocket side bearing into place and locked it with an e clip. Then I slid the assembly into the tube as far as possible. I slid the brake side bearing in and put in the e-clip. I used a nylon spacer to determine proper spacing for the drum brake and I put a fat old weld all around the axle.

I've done three long rides and success!

Too bad this is taking valuable time from my JagPipe project. I have a lot of welding yet to do!

 

[Frankenstein]

Update: despite my distrust, my flux core welding repair is holding, still feeling very solid.

I had another problem crop up:

I use a jack shaft on the rear to kick the drive chain left about one inch. Originally, this was to kick the chain around a very wide motorcycle tire which turned out to be too heavy.

I kept the jackshaft. Reasons why:

1) Gives a good chain line from the motor. Gives a good chain line to the drive sprocket on the left.

2) Short motor drive chain eliminates the need for a chain tensioner.

3) Jackshaft allows to the addition of a jackshaft brake with the drum fitted on the right side of the bike.

All three of the connections to the stainless steel shaft employ slots and keys. Just as I repaired the frame (for now???) I had trouble with my outside (sprocket drive) sprocket losing grip with the shaft. The original key broke.

No prob, right? I got a small stainless steel screw and grounded into a perfectly sized key and hammered it carefully into place. That key lasted about 3 days before disintegrating!

So, today, I went to Lowe's and bought a 3 ft piece of 1/2" steel rod. Not stainless, but the weldable type. I cut the shaft to proper size and scored the shaft in the right places to receive the e-clips for the bearings.

The tube I use to hold the assembly are those fence couplings with 1 1/2" diameter. Very strong! I just allowed the pipe to sit in the bracket, held in by pressure. I ground up the contact points and welded both sides into the bracket.

I had to pay attention to building up the shaft - didn't want to back myself into a corner. Those fence couplings have and indentation in the center and you can't just push the bearing through. I placed the inside e-clip for the brake side bearing and, with the bearing as far away as possible and covered I welded the inside sprocket into place. After grinding was done, I placed the outside sprocket into position and welded the outside. There wasn't enough room to get to the inside. I can't imagine that it's necessary!

I ground off the slag and it all looked decent. I slide the sprocket side bearing into place and locked it with an e clip. Then I slid the assembly into the tube as far as possible. I slid the brake side bearing in and put in the e-clip. I used a nylon spacer to determine proper spacing for the drum brake and I put a fat old weld all around the axle.

I've done three long rides and success!

Too bad this is taking valuable time from my JagPipe project. I have a lot of welding yet to do!

But as a learning experience the time you spent welding here will give you the ability to wizz through the pipe welding like it's no one's business. Hopefully at least.

In hindsight don't you feel better that you are relying on something you personally hand constructed rather than on a chip of metal made on the other side of the planet with no regard to your specific needs?

Of course you do!

 

[Frankenstein]

Oh and for a time one of my jackshaft keys was a bent off screwdriver (emergency repair) and later for the better half of a year an allen key (good grade steel key) that I ground 2 sides off to make fit in the slot perfectly.

Without the challenge these bikes wouldn't be very fun at all...

 

[Timbone]

I used to get paid big bucks to weld, but it was always with good equipment: stainless stick, MIG with real shielded gas and some TIG on aluminum. The set up with the foot pedal gas control - even I could run good beads with that set up.

In the backyard with a cheapo flux core welder is a different thing entirely. But I have a good angle grinder and bench grinder. That helps. I am more of a grinder than a welder.

I did buy a spool of good Lincoln flux core wire and that is an improvement. Only a fraction of the spatter I was seeing before.

It's too bad for us backyard welders that most bike frames are made of CroMoly steel - a steel that can't take welding without major consequences. That's why I will never be able to trust my frame repair regardless of how strong it seems.

Welding up the 22 gauge for the expansion chamber has been challenging so far. Move too slowly and you'll make a hole. I am optimistic that the better quality wire will make it much easier and cleaner.

When I get the JagPipe together I'll provide pics and a review.

 

[Street Ryderz]

I used to get paid big bucks to weld, but it was always with good equipment: stainless stick, MIG with real shielded gas and some TIG on aluminum. The set up with the foot pedal gas control - even I could run good beads with that set up.

In the backyard with a cheapo flux core welder is a different thing entirely. But I have a good angle grinder and bench grinder. That helps. I am more of a grinder than a welder.

I did buy a spool of good Lincoln flux core wire and that is an improvement. Only a fraction of the spatter I was seeing before.

It's too bad for us backyard welders that most bike frames are made of CroMoly steel - a steel that can't take welding without major consequences. That's why I will never be able to trust my frame repair regardless of how strong it seems.

Welding up the 22 gauge for the expansion chamber has been challenging so far. Move too slowly and you'll make a hole. I am optimistic that the better quality wire will make it much easier and cleaner.

When I get the JagPipe together I'll provide pics and a review.

I use mig with flux core 30-35 wire with the feed rate just past half and heat(amprage)on low for doing exhaust work!With the heat low and the right feed rate you can still work the puddle with out blowing thru and little spatter by staying in real close and feeding into the puddle as you pull back to try and lay it at the same as the feed rate,As soon as you see the puddle heat penatrate at a start point move on and pull it back by feeding into it that way your not in one spot long enough to blow thru and the spatter is controlled from being in close with less chance of the wire feeding off to the side a bit from the puddle witch is why most spatter occures!Your frame can be repaired and made stronger than it was when new!What i do in those cases is make an insert with some nice thick walled steel tube rectangle shaped in this case bevel the edges of your cuts on the stay so as to have ample meat left after dressing the welds and it wont break there again!

 

[Timbone]

Good advice! I'll be thinking about this tomorrow as I weld! Thanks!

As for filling in the frame with support steel, yeah, I can pull it off. If my outer wrap idea fails, I'll do some cutting and follow your advice . That will be a pretty big job!

Thanks!