Motobecane 500ht + CY460R + SBP freewheel

Discussion in 'Frame Mounted Engines' started by dchevygod, Feb 21, 2016.

  1. dchevygod

    dchevygod Member

    I have most of the logistics worked out in my head. To start with a new bike,

    Then a CY460R

    Mated to a 5:1 pocket bike transmission

    Use a center mount plate for a 4 stroke

    An SBP freewheel crankset

    And this is where I need help. I know I need the SBP freewheel, adaptor, I just need one sprocket for the crank to wheel connection but what size if I'm already at 20:1?, because I think the 11:44 cogs I have will work for the trans to crank connection.

    I need help choosing the correct bottom cartridge, crank arms and spacers to get it centered with a good chain line and clearance.

    Perhaps some of you guys running the 4stroke shift kit could chime in with pics of your bb, sizes and sources for them.

    Any help, comments or feedback are greatly appreciated. Its been to long since my last build. Time to do it up right!

  2. dchevygod

    dchevygod Member

    Alright now I am awaiting for parts. Just put in the order for mostly everything. Just need the bike :) I am going to check out the options here locally before ordering the one I linked above.

    I hope I got the right ratio. I got the 23t sbp sprocket just cause its the smallest they had. So its 24.54:1 x 23t:32t so it's .72:1 right? , for a final drive of 34.14:1 in 1st, am I doing something wrong here?

    I already anticipated the 44 t would be too high of ratio. So I got 11:54 from the 5:1 to the freewheel then 23t to the 8spd cassette "till I get a sturmey 5spd."
    Last edited: Feb 22, 2016
  3. dchevygod

    dchevygod Member

    Couldn't get the 500ht so I'm getting a black 400ht. I wanted the matte Grey 500ht but oh well. I looked at the biggest bike shop here and couldn't find anything that would work. The Trek 3500 they had oblong frame tubes :( and that was the only option to look at so. I just ordered the 400ht and know that it will be adequate. As soon as the parts arrive I'll take plenty of pics unboxing and test fitting.
  4. Looks sweet that same site has a twin motor that caught my eye. Keep us up to date

    Im building a cag bmx 8hp water cooled theres some crazy engines out there that are 10 times better then these tin can ht's
  5. dchevygod

    dchevygod Member

    Thanks Charles.

    I think its gonna be awesome. I give words of caution on those cag engines. Almost everyone I've seen has an issue somewhere.

    The 4.2 HP rating on my 460 is kinda conservative. I estimate the power to be closer to 5hp, as my first one would pull 51.4 on the flat! It had a left side axle mount at 20:1 on 26" kenda slicks ;)
  6. Hmmmmm im going to go with you on this i ordered the 460 but with the jackshaft kit it takes 10% power so im jus going to rig it up to a left side sprocket. Do u have pics or vids of ur first one.
  7. dchevygod

    dchevygod Member

    Um I'm not using the sbp jackshaft. Using a 5:1 reduction that reverses rotation. I did the same before on this axle mount. It has a g43 on it in this pic though. It was a 20:1 ratio single speed LSD, and with a stock 460 it hit 51.4 top speed on the flat.


    Attached Files:

    Last edited: Feb 24, 2016
  8. dchevygod

    dchevygod Member

    So mounting in frame single speed I think I would use the clutch housing the motor comes with and make a rear sheave/ pinion pulley and belt drive the thing!

    Get close to the 20:1 ratio for speed. And it would be a bad ass motorcycle throw back bike.
  9. dchevygod

    dchevygod Member

    Dang you brain!!!
    Now I need another bike to build. I have the g43 that would be fine in either build. I'll look for a steel cruiser frame to build the belt drive on. LOL probably next tax season.
  10. Well now iv seen engines mounted everywhere (handle bars, center of frame, back rack, front rack, trailer)
    But never a axle mount. hows that work in your personal opinion?
  11. dchevygod

    dchevygod Member

    Well. Very well on smooth roads. When I moved from flat land paradise to pot hole hell it didn't hold up but it could be over engineered to handle it. That wheel made the build happen. Its an ezip electric converted to gas very simply. I have the hub and sprocket still but the hoop is trash, the 1/4" mount plate was twisted!, 5:1 reduction gears eaten and got trashed right after the failure out of anger.
  12. dchevygod

    dchevygod Member

    How'd you like my bike smoking the fastest Goped on the track! ;) he was coming fast though he did catch me at the end of the run. He had a fully modded 460 making probably 8+HP in my defense though lol.
  13. And the motor he has im going to make haha but mainly because im going to try to jackshaft it with a 2 speed hub
  14. And verry nice sir ;)
  15. dchevygod

    dchevygod Member

    Engine has arrived. I got the low rpm clutch springs and installed them. I haven't mounted this motor from the bottom yet, and apon inspection I see that the bottom mount holes are 5mm not 6mm like I had hoped :( well its not that bad I can use 5m bolts and the bolt will be the weak point to save the motor case from breaking if anything were to happen. The bottom mounts aren't even so some spacers on the clutch side will be needed. With some extra bolts and spacers, a few well placed drill holes and some chain making Ill be riding. When all the parts get here...
  16. dchevygod

    dchevygod Member

  17. dchevygod

    dchevygod Member

    But beware the 460 is notorious for breaking clutch springs. Keep a set with u and the tool that comes with the engine if u use #27 torx bolts to attach the trans/clutch housing. The tool it comes with is invaluable. Loctite is our friend!
  18. skyash

    skyash Active Member

    Looks like the same motor I got. A 49 cc so called racing pocket bike motor every thing sounds the same but mine is 3 to 4 hp. So your motor is off a scooter? The pocket bike motors go up to like 15 hp but that cost a lot more. And I have heard of pocket bikes and scooters doing over 80kmh
  19. dchevygod

    dchevygod Member

    Yes this engine is used on the stock goped scooters. It is not a pocket bike motor. They are easily upgraded and plentiful. The motor on my axle mount in the pic is a g43 " the early big bore goped motor " the 460 is more powerful but the g43 is nearly bullet proof.
  20. skyash

    skyash Active Member

    What speed are you getting? Do you need to pedal? Thanks