New Build, 5 sp Chopper @ over 40+ mph

Discussion in 'Performance Mods' started by Byron, May 6, 2009.

  1. Byron

    Byron New Member

    Fairly new to the forum, and have asked for a little assistance, but no response, so I went at it cold turkey. Now I've been building Mustangs and Cushman's for some time, so fabrication is not new, and I thought it would be fun to build a wild motor bike. So here is what I've come up with. It is an original OCC Chopper, w/ RAW 80cc(??) ported engine. It is built up with a aftermarket clutch actuator from a gentlemen in Florida I found on this list. It also has a SBC shifter kit that I had them make for a 'center' mount along with their expansion chamber exhaust. The bike is set up with a rear 5sp gear
    freewheel w/ an axle mount derailleur and a custom mounted 200mm disc and Apex (I think) disc caliper. I could not figure out a way to mount a disc on the front wheel because of it's shallow disc and being to close to the forks for a caliper to fit. So I found an old bike frame that had a squeezer type of single point caliper that I mounted to the Chopper frame with a welded on mount that I made. Using a dual line hand lever I was able to adjust the brake bias to be as perfect as I could have hoped for. I still have some bits & pieces to attach like mirrors, maybe a stop light etc. I have clocked this Chopper at a whisker over 40 mph wound out in 4th gear. I think I'll just use 5th gear for cruising as I don't bounce anymore, I just splat......Byron

    Attached Files:

  2. azbill

    azbill Active Member

    nice looking OCC !!!
    watch the tank mounts, they tend to crack where bolted/screwed to frame
  3. Zev0

    Zev0 Member

    All I can say is SWEEEEEEEEEET!!
  4. echotraveler

    echotraveler Member

    oh my! you've done a great job! how long have you been doing this?
  5. Pablo

    Pablo Motored Bikes Sponsor

    Nice build! One of the only chopper Shift Kit bikes out there. I think you have done excellent work, taking your time and doing things right. I also think you are in "unexplored" territory, so maybe that's why people havn't poured in a ton of "help".

    For example, I would need to see the disc brake set-up up close and personal to comment.

    As for the Shift Kit install two things I can comment on (again can't see everything in photos):

    Your driven BMX chain is loose (obviously), and it seems like there is little you can do to tension it, have you tried a half link? Tensioner? Just a thought.

    Also, since it appears you didn't/couldn't use the supplied rear mount, there is nothing tieing the right mount for added rigidity. Has this caused any problems? We could come up with some ideas.

    Anyway - one word: SWEET!!!
  6. butch27

    butch27 Guest

    That is just NICE!
  7. Byron

    Byron New Member

    Chopper Brake

    Hi Pablo:
    I'll try to address your queries as time allows. Here's the first installation. As the pictures show, I felt that if the method of chain ring mounting (spoke sandwich using heavy belting material) was strong enough to apply engine torque to the wheel, then it would work to 'stop' the wheel. I cut out the center of a chain ring used on the 'flex mount' and used it as a basis for mounting the disc. It wasn't to much trouble to true the disc with the wheel, and it seems to be holding. Once the disc was mounted, and the wheel on the bike frame, I just had to mount the caliper, find an appropriate location and back spacing, fabricate a mount and attach it to the frame. Out of time for now.......Byron

    Attached Files:

  8. NunyaBidness

    NunyaBidness Member

    While I'm not an expert on disc brakes, I think you may have problems breaking spokes with the way you have the disc mounted. Other than that you have built a great looking motor bike.
  9. Byron

    Byron New Member

    Breaking spokes with the disc

    As I said before, I gave a lot of thought to this. I figured that if this type of mounting (same as used on the original style drive sprocket), could be used to drive the wheel, then it should be strong enough to stop the wheel, seeing as how there is only a 3 sq. in. friction patch on the tire. Now if the situation was different, ie gobs sticky tire rubber, monster (wide) rear tire, then there might be a problem. During the process of balancing the front/rear brake bias, so as not to land on my tush, I've locked up the rear disc many times with no hint of spoke problems, things working loose etc. None-the-less, all of this creative stuff gets a thorough going over every time I crawl on this thing. Good brakes were the most important criteria in this build. I've had to much road 'rash' over the years to come up with another 'case'.:helmet:
  10. Disk Brakes

    I feel your pain. And you are my friend in pretty much uncharted water. I have found that whatever you have to do to make the disks work - is worth the effort. I have only had success with a hub that has the rotor mount. If you check out this hub from US Choppers it would probably lace right into your rim.
  11. jlebh1

    jlebh1 Member

    hey ive got a occ chopper (its one of the ones on the grubee website made for motorizing) with a 70cc HT how hard was it to fit the SBP expansion chamber? and I dont think that I could use the shift kit because my bike doesn't have gears for one and 2 if I could find a occ wheel that had gears I dont think that any in australia came out with gears.
  12. Byron

    Byron New Member

    jlebh1 Chopper Work

    To bad I don't have a first name, it's always nice to address a real person. Don't panic, all can be done. First of all, not being at all familiar with bicycles, I don't know the difference between my first issue OCC Chopper and one from this 'Grubee' guy. First thing, you need 'good' brakes, that means 'disc brakes' if possible, which I couldn't put on the front wheel of my OCC. The original rear brake on my OCC fell apart on second stop. Kind of hard stopping @ 25 mph by dragging your feet, enough said. Now, as far as installing the exhaust chamber, there is some welding required. As the enclosed pictures show The cutting and welding that's required is dictated by your motor placement, and how you want the chamber placed. As the picture shows, I like an 'up swept' look, and I think that the dimensions of the chamber fit my frame almost perfect (my opinion). Its just a cut and fit procedure. I also think it sounds great (not to loud). I got kind of picky on motor placement because I didn't like the looks of the motor being way up high, or to low so I modified the mount I received from the vendor to place the motor right in the middle of the frame. You can use the shifter kit from SBP quite successfully, although I had to extend the counter shaft so that the drive sprocket could line up with the placement of the driven chain ring. To complete the drive system, what you want is a 5sp gear w/freewheel (e-bay) and a axle mount derailleur. If you serious about going this direction, let me know and I'll dismantle my drive line and picture piece by piece the procedure......Byron

    Attached Files:

  13. pdxrhett

    pdxrhett Member

    those occ bikes look like a pain to put a motor on, but once it's on, it does look AMAZING
  14. jlebh1

    jlebh1 Member

    chopper pics

    hi again my name is Jake by the way, here are some pics of my chopper. You know how on your mount you bolt that onto the frame (I think) with mine from the grubee factory those 2 posts that you just have a plate with them on on mine they are welded on to the frame, and mine comes with a different hub so that the sprocket bolts on to the hub not on to the spokes.

    sorry about the mud in the pictures its been raining here well a couple of weeks ago but havnt got around to cleaning it too many other bikes as well as this one though this is my daily transport to and from work so this one is my priority, and I know the muffler is off its so you can see the mounting properly

    also thanks for the offer but dont take apart your bike yet there is a place here in australia that can custom make just about anything I want for my bike but ill PM you if I need those pics


    oh ye my bike also came with front disc brakes and just normal rear

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  15. Byron

    Byron New Member

    Chopper Build

    Hi Jake:
    Now I'm really jealous, a few weeks ago I'd given anything for your front disc brake. I'd really would like to know what the difference is between your Chopper and mine. The front wheel on mine has such a shallow disc that there is no room to mount a brake disc, and still allow the caliper will fit between the spokes and the forks. I think that the adaption of the tuned pipe will really transform the appearance of your bike. Have you done any porting. Doing some porting, along with the tuned pipe, will really make it sing. I notice your high bars. I've been toying with the idea of doing that, but first I need to raise the seat peg, as I'm a little long legged for this 24" machine. I might sell this exercise, and do the same thing to a larger bike that would be more comfortable. I'd be interested in seeing what you come up with......Byron
  16. Byron

    Byron New Member

    Can't, Shouldn't, Not Possible, Wouldn't do it.

    These are the reasons that set me off building this machine, and I ended up with a motor bike that's a total blast to ride, almost as much fun as my 20 hp Cushman 740.....Byron
  17. jlebh1

    jlebh1 Member

    ill take some close up pics of the front and rock solid motors here in australia is giving me a good deal on a ported and polished engine with balanced crank (means very little to no vibration) deltoro carb, clutch acuator, performance cdi and billet engine covers. so I can put the engine on iit now on one of my other old bikes and sell it and make a bit of profit along the way. by the way rock solid motors is the same stuff manic mechanic sells -

    (and this is only there baby HP engine:)
    Last edited by a moderator: May 29, 2009
  18. cpuaid

    cpuaid Member

    sweet looking bike, byron! great job on documenting the build with pictures. it will surely help others in the long run. as stated earlier, you're in uncharted territory with this bike. keep up the good work and happy riding!
    - chol
  19. llamaboydave

    llamaboydave New Member


    i really like ur bike byron but money and time wont let me doing something like urs. but i was wondering if u can make a vid of how ur drivetrain works.
  20. ENO

    ENO Member

    Another OCC

    Hey Byron..ENO (Down Under) Sorry I missed your first post..Great build and you obviously know your mechanics..My son and i have recently finished a Stingray,,Yeah they are a difficult build but well worth it..Jakes bike is a clean build (with attached mud stickers)..Ours (or my sons) is constantly evolving as his imagination gets bigger every day. Thought I would post some pics to add to the collection of Stingay ideas..will keep watching this thread for more ideas..see ya ENO (Oz)...(PS..The skull is temporary..I hope..but you never know.)

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    Last edited: Jul 17, 2009