OCC Chopper Bike Build

Discussion in 'Photos & Bicycle Builds' started by Timbone, Oct 9, 2016.

  1. Timbone

    Timbone Active Member

    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:

    Attached Files:

  2. Imthegrt1

    Imthegrt1 Member

    that the 20" frame you got there right not the 18?
    are you going with levers or you going to be using hand grips for your controls?
    what tank set up you going with belly tank?
  3. Timbone

    Timbone Active Member

    I have not seen many of these in the flesh, but I am pretty sure it's the bigger model. Rear wheel is 20" (16" motorcycle size) and the front wheel is 24".

    Since I have no money to waste, this will be a collage of levers: clutch and front brake on the left; rear brake on the right.

    I have no idea how to address the fuel tank. I'd like to fab up something. I could maybe braze up an aluminum tank and hang it somewhere. Another idea is maybe fab up a PVC tank lined with a fuel sealer that won't eat up the PVC.

    I don't like the idea of a peanut tank on the top tube.
  4. Timbone

    Timbone Active Member

    Update on my OCC Chopper build:

    I have run into a few roadblocks. Motor mount is good, but seeing advice on another forum, I bought a used Harley tire and got it on the frame. Unfortunately, I don't think I can keep the chains out of the tires. It looks cool as hell but I need to fab some chain tugs and I even have to lengthen the pedal chain. Just to get the tire on the back I had to remove the rear V brakes and squeeze it in past the welded brake tabs. This also forced the removal of the very cool rear fender.

    Maybe I can cheat the motor chain just enough to be free of the rear tire. If not, I may have to make a kind of transmission that can move the chain farther left. I really want to use the bigger motorcycle tire. All these costs add up.

    My triple tree is a mess. It has an exaggerated kick out that, combined with the extreme rake makes it very nearly unrideable. It has front V-brakes (good) but the threads on the fork are shot. Not sure how to fix this. Maybe buy a suspension MTB fork and roll with that. Sure would be nice to have front disk brakes. If I could make triple tree couplings that would facilitate the bearing I would be good to go.

    Glad it's cold weather time.
  5. Timbone

    Timbone Active Member

    OCC Chopper Build Update:

    This has turned into a Spring, 2017 project and I want it to be special. I've saved up some money now and I have options. The motorcycle tire looks so good on the back I really want I to go with the OCC frame. But...

    The left side drive chain cannot clear the big rear tire. That forces 2 changes (I've already made my custom offset motor mount):

    1) The drive sprocket has to be offset to the left so that the chain can clear the tire. I have an excellent idea for making a kind of jackshaft to move the drive gain 3"4" to a full inch left. I can make this work.

    2) The rear triangle is too tight to allow chain clearance. I have access to a welder, planning to cut the left side chain stay and seat stay and making it a full inch wider. Here's where my problem lies:

    Moving the axle mount one inch left puts it near the end of the axle. How can I safely extend the axle an inch or an inch and a half so that I can use this rim/tire combo?

    Also, I'll need to rig up a sprotor braking system for the rear. The rear rim brakes will be out of play.

    For the front fork, I am hoping to find some moped front end with suspension to work into the triple tree, which is a mess.

    Any advice or ideas you have will be helpful. I can't afford to waste a penny on this.


  6. Street Ryderz

    Street Ryderz Well-Known Member

    this is the last one I built with welded mount the chain clears and breaks still work no problem!

    Attached Files:

  7. Timbone

    Timbone Active Member

    Very well done! Looks great!

    I have questions:

    About your front end: is that suspension? Do you have a front brake? My bike with 24" front wheel and 16" rear was incredibly hard to handle. How does you bike handle?

    Is you saddle comfortable?

    I am putting a Harley tire on the back, 130/90-16. This is what makes things complicated. If I can do it, it wil have a super smooth ride for a hard tail.

    Thanks for sharing; every bit of info I have helps!

  8. Street Ryderz

    Street Ryderz Well-Known Member

    There is no suspension just stock occ Schwinn it was built for my youngest son when he was 11 and now he wants a drag bike so it reverted back to me its really just a cruiser so no i haven't put disk fronts or any thing on it yet!And to be honest I dont trust the triple trees or the fork tubes for that matter to handle a good disk set up with adult weight,I know alot of people do but seems sketchy to me!The wheels are 24'' front and 20'' rear but the 4'' wide rear has alot of sidewall that brings it to 23'' or so the handling is good again for a cruiser!Someday I will strip it paint it up nice I just keep it because it looks really cool to me! and yes that seat is good to ride on not so much if you have to peddel though to wide!
    Timbone likes this.
  9. Timbone

    Timbone Active Member

    image.jpeg OCC Chopper Build Update:

    I am starting to get excited about this project. Making progress!

    That engine is old, used only for fitting purposes. But my custom motor mounts are complete and ready for the new engine.

    You can see I have successfully mounted a Harley tire (130/90-16) on the back. Very cool but brings several challenges.

    My high speed bearings arrive tomorrow and I can bolt my very cool jackshaft onto the seat tube that will kick the drive chain around the big tire.I'm using a conversion down to 9 teeth for the drive shaft, so I should be able to use a 36 rear sprocket. I'll put pics on here to show you how to make a cheap jackshaft. Biggest cost was the very nice sprockets I got for about $25.

    I need to fab two chain tugs.

    I am going to fab a sproter rear brake, probably using a thick cam to actuate the brake arms. My plan, completely in my head, is coming together.

    Still need to kick the right side pedal chain slightly to the right to clear the rear tire. A poster on here suggested bolting a larger cog onto the existing freewheel cog. Possible. Maybe I can use a spacer the chain wheel. I only need to move a a little.

    I am going to work with the existing front fork set up. That wheel in the pic is a 26" - I'll try the original 24", but until the bike is really rolling (there's no lock ring on the headset - in the mail) I have no idea how it will handle. Too much rake and too much offset angle.

    I am going to find a fat seat post and chuck the original saddle. Big fat cushy spring saddle is the way to go.

    I still need to buy a kit and use a dellorto clone carb.

    This thing looks so rough, but I have put many hours into the project so far. I plan to have it complete by March 15.
  10. Street Ryderz

    Street Ryderz Well-Known Member

    looking good! love the back tire but its mounted backwards,It will look cool but being so small not sure about handling.Just be careful when you first ride it!
  11. Timbone

    Timbone Active Member

    You have a good eye! It's too much trouble to correct the rotation direction mistake! Hard work mounting a motorcycle tire with hand tools!

    I cut a 25T Ultegra cog from a cassette block - it will fit perfectly, allowing me to move the pedal chain 3/8" to the right and off the big tire.

    I have all the parts for my jackshaft. Just need to sit down and take some very precise measurements to know exactly where to lock in the sprockets, bracket and bearings. I'll put pictures up.

    I think it will look better with a more regular saddle.

    Thank you for the compliment, sir.
    Street Ryderz likes this.
  12. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Offset (what I'd call rake) is there to offset the excessive trail that would otherwise be caused by the extreme rake (what I'd call head angle).
    (Sorry I'm such a pedantic tw!t, I think it's a mental health issue.)

    A fork with less "offset" would not offset the trail. The bike would be difficult to steer at low speeds. However if you just ride everywhere really fast it could be a good thing. Schwinn's designers didn't intend you to ride with engine power anyway.

    I think the 26" wheel looks right because it makes the frame level (since you raised the rear by putting a huge rear tyre on it).

    I'm not sure what dual crown mountain bike forks would fit the headset/head tube but I'm sure I have read about a moped or light motorcycle fork with a 1" steerer (and a specific wheel) being used in other motored bicycles in the earlier threads on this forum.
    I suppose it could get expensive but at least it allows you to mount a front brake and another motorcycle tyre on there could be pretty cool. :)
  13. Timbone

    Timbone Active Member

    Thank you for the input on this fork rake/ trail issue!!!

    I am an old bicycle racer so all I know is twitchy quick handling that comes from steep headset angle and little rake. I do understand these terms.

    When referring to "offset", I wasn't referring to rake or to headset angle. If you look at the triple tree, you'll set that it is offset - not parallel - away from the head tube angle. I'm thinking that, with the extreme rake, this decreases trail which may explain why the bike was barely rideable with a 20" rear tire and 24" front tire.

    I'd like to have a whole new triple tree while adding suspension, decreasing rake and keeping the fork tubes parallel to the headtube angle.

    What do you think? TIA
  14. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    I'm pretty sure that the only one with the 1" steerer is the old moped fork (and matching wheel) that is mentioned in some old threads here.

    I only know of one "real suspension" mountain bike fork (single crown) with a 1" steerer.. the Marzocchi MX Pro if I remember the name correctly, made as late as 2006.. but you said you don't want a single crown fork anyway.
    Last edited: Jan 26, 2017
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  15. Street Ryderz

    Street Ryderz Well-Known Member

    I wouldn't really use those triple tree from schwinn they are thin,weak and just scary to me!But there are many ebike front ends with suspension that will work!also many triple tree sets that can be adapted to accept enduro suspension tubes. or the jesse james set that will accept 2"plus dia tubes.
    Timbone likes this.
  16. Timbone

    Timbone Active Member

    Actually, my OCC Chopper bike is set up with a 1 1/8" threaded steerer which means I could use a threadless fork setup. I have plenty of options, but not a lotta money.
  17. FurryOnTheInside

    FurryOnTheInside Well-Known Member

    Then I would check eBay etc until you find some old Marzocchi Junior T's. The open oil bath system is very easy to work on, you will need to replace the bushings often with that head angle. Probably better check the availability of bushes tbh.
    You can overfill with 10wt oil to make it stiffer, shorten the travel a bit and then you can lower the crown's slightly I think, to shorten the fork. Junior T's had about 5" travel originally I think..

    I have put some old Marzocchi forks on an inverted bmx cruiser frame just to see how it would look. Idk which model of Marzocchi Bomber fork it is. It could be a custom mismatch of the top and bottom.. anyway I can feel the front wheel just wants to flop over because there is not enough rake for the crazy head angle. It might be okay with some kind of spring thing to help centre the steering, idk.. it's a future (electric uplift) gravity bike project and I am far from being ready to start. I don't mind that running the fork at this angle will undoubtedly ruin the bushes because I don't plan on riding it for many miles
    Last edited: Jan 27, 2017
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  18. Timbone

    Timbone Active Member

    image.jpeg image.jpeg Still making progress. I've bolted a 25T sprocket onto the pedal side freewheel moving the chain a full inch to the right to avoid the big tire. Picture provided. Had to add a 3/8" spacer.

    Also, I've fabbed up my left side jackshaft to clear on the left side. Here's a pic of the sprockets on the shaft.

    Also, prepped up my chain tugs so I can size and mount the pedal chain and make this a rolling chassis.

    Still need to bolt on my jackshaft bracket, set the shaft and lock everything into place so it's ready to take the 415 motor chain.

    I am pretty sure the rear V-Brakes will work so I can put my Sprotor project into the experimental file.

    Get a fat seat post, get a spring saddle and get a kit - this thing will be rolling!
  19. Frankenstein

    Frankenstein Well-Known Member

    You'll want to measure those 2 sprockets on the shaft, they look really wide honestly, and that might mean that you'll have a hard time getting a chain to fit them. On another bike we had a sprocket that was too large to fit the standard chain that comes with kits, we ended up putting it on the right side of a jackshaft shaft and turning the motor on to make the sprocket spin as I took an angle grinder to turn the width down to an acceptable size. Took nearly an hour of careful work so don't expect results in 10 minutes of you try something like that.

    I would think that twice as long with a belt sander and the right belt could do it too if you needed to do it without it spinning but you'd have to be careful to make the teeth all the same size or it might wear the chain out oddly or other similar problems.
  20. Timbone

    Timbone Active Member

    Thank you for the comments!

    First, about the pedal sprocket: it's a racing cog (Ultegra) that was part of a cassette block of the three biggest rings. They were held together by several small rivets and they took a long time to cut off! The new 25T cog is made of very hard steel. The ten bolts fit perfectly and I use nuts as spacers. Nothing can move as there is nowhere to go. The ring would have to shatter!
    I will take you advice and use blue thread lock on the outer nuts.

    These sprockets aren't very large. The shaft is 7" (that's what she said) and I was careful to order them specifically for 415 chain. I've test fitted and they are perfect.

    I had the a similar experience on my previous motorbike, being forced to carefully grind down each tooth on the one piece crank that wouldn't accept my BMX chain. No fun!

    Thanks for the input!