Questions about building my first motorized bicycle!

GoldenMotor.com

Zac

New Member
Nov 14, 2012
16
0
0
Louisiana
Hi! Before i start i just want to say this will be my first motorized bike build (and my first forum post!). The reason i want to build a motor-bicycle is just for fun, not transportation, mostly just to mess with the simple little motor.

-I was looking at this motor kit to buy, any comments/suggestions on this kit or a different or better kit to buy? ( i want to use a two stroke common little 66cc chinese motor and plan to port, pollish, and modify the little thing as much as possible, just want to make sure you guys think this is a good starting point) http://www.bikeberry.com/gas-engine...tors-silver-66cc-80cc-bicycle-engine-kit.html
also considering this : http://www.bikeberry.com/gas-engine...-80cc-angle-fire-bike-engine-kit-epa-cer.html
and this: http://www.bikeberry.com/gas-engine...per-rat-silver-66-80cc-angle-fire-bike-e.html

-This is the bike i have, you guys think the engine kit would fit on this easily? i think it would make a great looking motorized bicycle! I plan to mount the gas gas tank under the top bar of the frame, cut the frame part that the seat goes into 2 inches to lower the seat even more, and maybe reinforce the pieces holding the fenders (they seem a little too flimsy for my liking).
does this bike look like an engine kit would fit no problem? heres a closer picture of where the kit would be mounted:

also, it has a 3 speed hub, with shifter on the right hand bar, i was wondering if i could just get a new front wheel from the company, put it on the back, and put a small sprocket on there to make it a single gear to the pedals, and get rid of the shifting? just to make things simpler, as i would just be pedaling to start the bike really (or if i could somehow switch it around and have it attached to the motor chain so i could shift the bike that would be awesome)


Any help would be greatly appreciated!
-Zac
 
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GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
Welcome to the forum!

bikeberry has earned a bad reputation as of lately.
I would not recommend them.
I do recommend thatsdax though.

I highly doubt that an engine will fit into that frame, but without looking at it personally, you might be able to squeeze one in there? Somewhere around this site are the recommended minimum frame dimensions. I'll look for them.

Don't use a front wheel and try to attach sprockets to it. You are only creating a big headache for yourself.
You have better options.

Get a standard rear wheel and spin on a single speed rear pedal side sprocket and use a PITA rubber mount rear engine sprocket.

Get a coaster brake single speed rear wheel and use the PITA rubber mount rear engine sprocket.

Get a coaster brake single speed rear wheel and use a Howard sprocket adapter, Sportscarpat adapter, MM adapter, or one of the recent MM knockoff adapters.

Get a rear wheel with a hub made for a disc brake and spin on a single speed pedal side sprocket and use either an adapter to bolt on a standard engine kit sprocket to the disc mount or a sprocket made to attach directly to the disc mount.

Get an SBP jackshaft kit and use whatever rear wheel you want and use the pedal chain only.
Warning: Alot of the internal geared rear hubs cannot take the abuse that an engine and SBP jackshaft puts them through.

Above all, Get better brakes, front and rear!.
Going faster is only half the battle, stopping is the other half. If you cannot stop faster than you can go you soon may go splat into something unintended.
 

Zac

New Member
Nov 14, 2012
16
0
0
Louisiana
hmmm im searching for the minimum requirements, if i had too, i could take off the chain guard and put a new, smaller sprocket on the pedals for a bit. I really hope i can squeeze an engine into this frame, i love the looks of that bike! Also, im looking on thatsdax.com at their kits, thanks for the advice!

(i really hope i can use this frame, the other bike i have isn't nearly as pretty. haha)

Edit: just checked the other bike, its even smaller. so if this bike doesn't fit ill have to buy another bike :/
any way to make custom mounts to have it closer to the bottom of the frame?
 
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JonnyR

New Member
May 13, 2012
1,203
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ronkonkoma, new york
i like bikeberry they have been good to me i have a flying horse 66cc from them its a great kit
if you get the measurements and it would fit im not sure because if the cross bar
 

Zac

New Member
Nov 14, 2012
16
0
0
Louisiana
Yeah that cross bar is worrying me more and more. it looks like it would atleast hit the carburetor. if so i could just make a curved intake so the carburator would be sitting outside the frame.
 

GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
Well there ya' go!
A custom intake manifold and custom engine mounts are all I see that would need to be made.
It does look good too!

Edit: looking closer at the picture it looks like the front mount is one of the "drill a hole through the frame" mounts.
Do NOT do that to your frame unless you can weld in a sleeve to fully support the frame tube and bolt.
 
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Zac

New Member
Nov 14, 2012
16
0
0
Louisiana
Thank goodness!! i was terrified there for a second! Also, that is exactly where i want to mount the gas tank! What do you think would go into the custom mounts? just cutting down the stock ones, or starting from scratch? Also,
I was thinking this motor now: http://www.rawmotors.com/GRUBEE-201...-Head-Bike-Motor-Kit-Standard-Finish-p98.html seems to be pretty common, with lots of aftermarket parts.

I think ill order that soon, and in the meantime cut the part of the frame the seat post goes into down a few inches!

-Zac
 

Zac

New Member
Nov 14, 2012
16
0
0
Louisiana
Well there ya' go!
A custom intake manifold and custom engine mounts are all I see that would need to be made.
It does look good too!

Edit: looking closer at the picture it looks like the front mount is one of the "drill a hole through the frame" mounts.
Do NOT do that to your frame unless you can weld in a sleeve to fully support the frame tube and bolt.
hmm, couldnt i just make a clamp out of some thin sheetmetal for the front mount? i dont want to drill anything into the frame that could weaken it
 

Zac

New Member
Nov 14, 2012
16
0
0
Louisiana
Thanks! im not bad with tools, and i have a friend with a welder, so im sure i can come up with something!!
-Zac
 

Zac

New Member
Nov 14, 2012
16
0
0
Louisiana
Sorry for posting so many replies, but i just though of something, Would an angle fire slant head or a standard head be easier to fit? wouldn't the slant head have a lower profile from the spark plug to make it easier to fit in the ridiculously tight space on my bike?
 

JonnyR

New Member
May 13, 2012
1,203
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ronkonkoma, new york
i have a 7 speed schwinn and yes the gears are nice to have if something happens and you need to peddle it has happened to me and i wont buy a bike without them now

also if you get a replacement hub/wheel get one with a disk brake mount and then get a bolt on engine drive sprocket so you dont need a rag joint or a hub adapter
 
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Zac

New Member
Nov 14, 2012
16
0
0
Louisiana
i have a 7 speed schwinn and yes the gears are nice to have if something happens and you need to peddle it has happened to me and i wont buy a bike without them now

also if you get a replacement hub/wheel get one with a disk brake mount and then get a bolt on engine drive sprocket so you dont need a rag joint or a hub adapter
ok thanks! but i think im going to stick with leaving it how it is for now. atleast untill i get the kit installed. Im still pretty worried about making it fit.
 

JonnyR

New Member
May 13, 2012
1,203
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ronkonkoma, new york
the engine makes peddling heavy if you cant down shift i have to shift down to 1st if i need to peddle it more than just to start it or pull away from a light/stop sign for that i use 3-5 depending on if im in a hurry or want a work out 5,6,7 are almost unusable though
 

bigbutterbean

Active Member
Jan 31, 2011
2,417
3
38
Lebanon, PA
All that room between the top bar and the cross bar, and you want to use the kit tank. Where is your ambition, lol? Why not make a tank that can fill that whole space (or maybe leave an inch above the cross bar so the gas tank isnt right next to the head), and can probably hold a lot more than 2/3 of a gallon (what the kit tank holds). And for kicks, make the tank kinda bubble shaped on the sides, but still square on the bottom. Just a suggestion. Have fun, good luck, and welcome to the forum.