Motobecane 500ht + CY460R + SBP freewheel

dchevygod

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I have most of the logistics worked out in my head. To start with a new bike,
http://www.bikesdirect.com/products/motobecane/5ht_new_xii.htm

Then a CY460R
http://www.davesmotors.com/chung-yang-146224460-gp460-engine-4-2hp-cy.html

Mated to a 5:1 pocket bike transmission
https://www.pocketbikeparts.com/scooter-gearbox-33cc-43cc-49cc.html

Use a center mount plate for a 4 stroke
http://www.bikeberry.com/heavy-duty-4-stroke-mount-plate.html

An SBP freewheel crankset
http://www.sickbikeparts.com/catalog/index.php?cPath=21&osCsid=jv8nhr39fi52c8udjdr192r4n3

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!
 
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."
 
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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.
 
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
 
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 ;)
 
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.
 
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.

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.

 

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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.
 
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.
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.
 
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?
 
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