New Project

Discussion in 'Motorized Bicycle General Discussion' started by Mike Stroz, Jun 14, 2016.

  1. Mike Stroz

    Mike Stroz New Member

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    I'm just starting to gather parts for a new project I'm starting on. It's going to be a bike similar to the ones msrfan builds, on an old Columbia frame with a Briggs 5hp squeezed in with moped front fork, hubs, and controls. I haven't started any actual work yet, but I picked up the frame and a parts moped yesterday (which I just realized probably won't work). It's gonna have a torque converter and probably rope start (not recoil) and should hopefully go really fast. I think I'm gonna make it look kind of like a dirt bike with pointed bobbed fenders and a loud exhaust. I know I don't want to use the stock carb on the 5 horse, so what carbs are a good fit for a stock engine? And is there an off the shelf intake for a motor mounted at about 45 degrees? I'll post some pictures as I start building it, hopefully soon.
     
  2. Agreen

    Agreen New Member

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    I really like the PZ19 carb for larger 4 strokes. It will require a custom intake, pretty much no matter what.
     
  3. msrfan

    msrfan Active Member

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    Hey Mike, how about some photos of the parts you've got so far?
     
  4. Mike Stroz

    Mike Stroz New Member

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    Let's see if this works. Here's a link to my photobucket album that has the pictures:
    <div style="width:480px;text-align:right;"><embed width="480" height="360" src="http://pic2.pbsrc.com/flash/rss_slideshow.swf" flashvars="rssFeed=http%3A%2F%2Ffeed1045.photobucket.com%2Falbums%2Fb458%2FMikeStroz%2FMobile%2520Uploads%2Ffeed.rss" type="application/x-shockwave-flash" wmode="transparent" /><a href="javascript:void(0);" target="_blank"><img src="http://pic.photobucket.com/share/icons/embed/btn_geturs.gif" style="border:none;" /></a><a href="http://s1045.photobucket.com/user/MikeStroz/library/Mobile%20Uploads" target="_blank"><img src="http://pic.photobucket.com/share/icons/embed/btn_viewall.gif" style="border:none;" alt="MikeStroz's Mobile Uploads album on Photobucket" /></a></div>

    The frame is a 60's Columbia (unknown model), the fenders I cut down I think came off a Western Flyer bike from the 40's, the engine came off (I was told) a sidewalk sweeper, and is in almost perfect shape, excellent compression and spark, started on the first pull. I got it because it had a gear reduction unit and I knew I needed those holes to mount the torque converter, but what I didn't realize is that it had a spline shaft instead of the normal one with a keyway... I think I need to find either another motor and swap the crankcase cover, or a different crank... And the Motobecane moped is what the wheel hubs, fork, handlebars, controls, and maybe some electrics are coming off of. Not off of that exact one, since I actually ride that around, but basically the same model and same pieces. Any suggestions for the gas tank? I haven't found one I really liked yet.
     
  5. Mike Stroz

    Mike Stroz New Member

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  6. Agreen

    Agreen New Member

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    Well, that does work, but it takes us to your album. If you go to the picture and click "share", "get links", and then copy the url that says IMG. Paste that here, rinse, repeat.

    [​IMG]
     
  7. Mike Stroz

    Mike Stroz New Member

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    Just got an old pair of Atom moped hubs off a Motobecane. The guy I got them from has the rest of the pieces I need, but he has to dig them out of a huge pile of parts before I can get them. The hubs are in great shape and just need some cleaning and they fit in the frame like it was meant to be. I've brought them to 2 bike shops so far to have the rims laced on, but they both refused for "liability reasons" even though I told them the wheels are for a cruiser bike with no engine... So now I have to find someone to build those wheels for me... (I tried before and it didn't turn out all that well)
     
  8. Ludwig II

    Ludwig II Active Member

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    You will need to source thick diameter spokes for those hubs, I found out when we started putting my project together.
     
  9. Mike Stroz

    Mike Stroz New Member

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    Anyone know a place in MA or NH where I can get these wheels laced up? I have the rims and hubs but no spokes yet. I was thinking of trying a moped shop but I doubt they have the right size spokes for a 26" wheel. I did source a front fork that I can use, but the threads stripped out so I have a new steering tube thing on order (the thing the fork pivots on) as well as a nice set of controls that'll bolt right up. I'm thinking now that I might leave the thing without a motor for a little bit, just ride it around as a bike over the summer and throw the engine on over the winter.
     
  10. curtisfox

    curtisfox Active Member

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    Going to watch this build, love the briggs builds. Good luck with your wheels..........Curt
     
  11. Ludwig II

    Ludwig II Active Member

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  12. Mike Stroz

    Mike Stroz New Member

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    [​IMG]

    Just got a few more pieces of the bike together. I think the fenders came off a JC Higgins bike from the 40's that I cut down to a point. The fork came off a Motobecane 40t (I think) and the wheel hubs I have no idea about, but the rear is an Atom and the front says Brevette. The handlebars are off an old Raleigh, but I might put on the stock Motobecane high rise bars instead.

    [​IMG]

    I also got a cheap center stand and realized that one of the pdeals is bent and hits it while the other doesn't... Should be pretty fun even just as a regular bike! I'm thinking I definitely need a layback seatpost though. And I still need to source a tank.
     
  13. Tony01

    Tony01 Member

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    Cool project. Yeah that splined shaft might be a problem. Talk to MSRfan he's the master builder of 5hp flathead bikes. A pz19 carb is going to be too small for the 5hp. In fact I'm putting a pz19 on my 3.5hp Briggs. You will probably have to make your own intake. There is a guy on here that uses a 28mm carb on his 5hp raptor, I think a 22mm carb would be a good size for a mild 5hp build and you could always upgrade later if you do any more to it.
     
  14. Mike Stroz

    Mike Stroz New Member

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    I have been talking to him, I kind of "copied" his ideas for mine, but mine's gonna be a different style. I ordered a chinese 22mm Keihin carb for the motor. Always a gamble when you order a chinese knockoff, but I've had some good luck with them. So far... I should be picking up another briggs 5 horse this Wednesday, and if it doesn't have the mounting holes for the torque converter, I'll just throw on the gear reduction side cover that does have the right holes
     
  15. Mike Stroz

    Mike Stroz New Member

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    Just straightened the crank reasonably well in the vise, cleaned out the old bearings and greased em up along with the hubs and fork. Called around to a few bike shops today but still no dice on the wheels
     
  16. curtisfox

    curtisfox Active Member

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    Maybe you could talk to one of the guys that do the lacing, and maybe they could do it at home for you?.......Just a thought..........Curt
     
  17. ajoh

    ajoh New Member

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  18. Mike Stroz

    Mike Stroz New Member

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    I tried building wheels before, but it didn't work too well... Maybe someone on here would be able to build a set of wheels for me?
     
  19. ajoh

    ajoh New Member

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    just follow the video pause it, rewind it, play it again an again it's extremely easy to follow an you wont know until you try

    i did it never having built a wheel ever before an i've done 3 more since.............
     
  20. Tony01

    Tony01 Member

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    JUST DO IT!! I can do it, all the ppl in this thread can do it, and soon you will too.

    First thing you need is spoke length and gauge. I've never seen an Atom hub up close but they're likely made for thicker spokes. You can buy cheap thick spokes from husky bicycles. Also you can get Sapim 13g stainless spokes which are very strong and use washers with them, but might as well go with 12 or 11g right away. To find the right length you'll need to accurately measure the hub Spoke Hole Circle Diameter/Bolt Circle Diameter center to center of the holes, and the flange separation center to center. Try to get this within 1mm or less- best to get it as accurate as possible. Then you'll need the Effective Rim Diameter or ERD and this is the diameter of the rim where the nipples seat. You can easily just measure the inside diameter of the rim and add the thickness of the rims or spoke hole eyelets or whatever will make it bigger (times 2, for both sides). Find a free spoke calculator online; I've used the one on the DTSwiss website and also some other one on another site. Input the Flange Separation, BCD, ERD, and 3-cross, put nipple length as whatever the supplier says they come with (usually 12 or 16mm) and you'll usually get a number like 270mm for regular MTB rims and hubs down to around 220mm or so for very large bicycle drum hubs. My rear hub has a 70mm drum brake and came out to 240mm spokes for 26" wheel with 48 spokes. Usually it falls between two sizes and if you go with the shorter size you might need longer nipples (i.e. 16mm vs standard 12mm) or if you go with longer you might need to grind the spokes off with a grinder after lacing and truing the wheel to prevent getting a hole in your tube.

    BEST TIP: for standard 3 cross lacing which is 95% of what you'll do with bicycles just remember this for every spoke crossing: OVER, OVER, UNDER for external spokes or UNDER, UNDER, OVER for internal spokes. You wanna do the internal ones first cause it gets messy trying to get an internal spoke in the right spot when all the other spokes are there. Also when you are near the valve hole, make sure the spokes near it are parallel to make putting air in easier. Also it doesn't matter if you have internal or external spokes leading. I've done it both ways and haven't found a difference. I just did it whatever way I started it.

    Also you can tune them by ear:
    http://sheldonbrown.com/spoke-pitch.html

    I've built maybe 25-30 wheels by now and trued up many more.. the first couple were the hardest.. heck one time my chain jumped and ate all the drive side spokes. Well I got some similar sized spokes from another wheel but they were too long. took hub and spoke length measurements and put them in a spoke calc, and found that 4-cross would work (more crosses require longer spokes.. 0 crosses is radial lacing..) so I ended up lacing the drive side 4 cross and my buddy still has the wheel with the rag joint on it no problems. Sure saved my butt that one time. I think the difference was only 8mm or so.
     
    #20 Tony01, Jun 29, 2016
    Last edited: Jun 29, 2016

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