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Motorized Mountain Bikes and Road Bikes Motorize a full suspension mountain bike to get a smother ride or for a little more speed try motorized road bicycles. This section is for sharing ideas on motorizing your mountain and road bikes.

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  #1  
Old 12-11-2016, 02:50 PM
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Patchy Patchy is offline
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Default 212cc build!

Hey folks, its been awhile since I've been on the forums but I have some news! After selling my motorcycle I started a new motorbike project! My other builds were with the China Girl 2 strokes and I wanted to move up in the world so I decided on a Predator 212cc engine.

My friend and I went balls to the wall and did as much as I could afford with the engine: new cam, connecting rod, advanced fly wheel, spark plug, springs, carburetor, governor removal, and a new exhaust.

I wanted a fattire bike for this build and after visiting a couple local bike shops I ended up purchasing a complete bike from Sikk bikes. The frame was slightly to small for the motor so I cut away at a two spots and wrapped them in fiberglass casting tape. I'm not too worried about the structural integrity because of the wrap, but only time will tell how well it holds up.

The 40 tooth sprocket and adapter I have is .25" to small for the rear hub of this bike so I widened with a stepped bit, it worked better than I expected the bit too. Initially the exhaust was directly over the seat tube so my friend and I bent it with MAPP torches. It took about five sessions of slow bending to get the pipe in the desired location.

I'm typing this thread as I'm waiting for the lock tight to cure, have about four hours left until we get to take the bike for a test ride. I have more photos here everyone should check out! I'm thinking of naming her Little Red, any other name ideas? Thanks for the read y'all have a good one.

P.s Anything else I should do to the bike besides installing lights and a rear discbrake?
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Last edited by Patchy; 12-11-2016 at 02:54 PM. Reason: Grammar
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  #2  
Old 12-11-2016, 02:58 PM
Seabass Seabass is offline
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Default Re: 212cc build!

Could you have just put a shorter valve cover on, instead of cutting the frame? The hemi predator has a shorter valve cover on it too, why not that one. On the go cart sites they have tons of upgrades for the hemi too.
Well way to be ballsy cutting the frame. i will be watching
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  #3  
Old 12-11-2016, 03:47 PM
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Patchy Patchy is offline
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Default Re: 212cc build!

I probably could have put a shorter cover on, but I never occurred to me to look! Oh well too late now.
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  #4  
Old 12-11-2016, 05:33 PM
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Default Re: 212cc build!

Great looking build. I think disk brakes and lights are good priorities.
Will you be riding on the street legally or is it an off road bike?
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  #5  
Old 12-11-2016, 05:36 PM
TheNecromancer13 TheNecromancer13 is offline
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Default Re: 212cc build!

Your gear ratio is way too steep, you're going to need to add a jackshaft or use a giant rear sprocket. Aim for between 8:1 and 10:1. It looks like about 4:1 right now.
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Old 12-11-2016, 07:48 PM
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Default Re: 212cc build!

There is so much wrong with this build it's not even funny.

1. You just f****d your frame. 212 woulda fit fine if you put it vertical maybe. No amount of fiberglass tape is gonna save you. That frame is gonna crack in one of those two spots and believe me it's gonna hurt. not even sure welding is gonna save you either. You can throw the frame in the trash!
2. No front brakes??
3. Gear ratio too tall. This isn't a 2-stroke with a 4.1:1 internal reduction. Your bike won't even move and the engine won't rev past governor rpm so all your performance parts were for nothing. You'll fry your clutch in the first hour. Either put a 65t sprocket on the back or get a jackshaft setup
4. I hope those are double wall rims!
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Old 12-11-2016, 08:07 PM
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Patchy Patchy is offline
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Default Re: 212cc build!

I would love to ride this bike legally on the streets, but I don't know Montana's laws in regards to this. More research is required. As for the gear ratio, you are right I need to find a larger rear sprocket. I was thinking of a 58 tooth gear.
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Old 12-11-2016, 08:29 PM
TheNecromancer13 TheNecromancer13 is offline
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Default Re: 212cc build!

58t still won't be nearly enough. A 90t might be just barely enough. Also look at tony's post, all of his points are valid.
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  #9  
Old 12-11-2016, 09:58 PM
Seabass Seabass is offline
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Default Re: 212cc build!

I think you need allot more gear reduction than that. Check them go cart sites, for about a bill you can pick up a CVT with a bracket that mounts to your motor. That would gear it down for you. I am worried about your wrap. Nhra frames are not powder coated, painted, or covered so a crack can be seen. Id unwrap and try to weld in some gussets to sure up the frame.
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Old 12-12-2016, 01:17 AM
ajoh ajoh is offline
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Default Re: 212cc build!

that frame...............Patchy i hope your life insurance is paid up, your loved ones will likely need it.....

that damn thing is an accident waiting to happen...........


a smart move would be to start AGAIN with a new frame, a 212 is not a toy take it serious FFS!!.........


breaking news, man dies/seriously hurt on halfassed motorized bicycle authorities look at harsher laws an restrictions (yet another black mark against motorized cyclists).........
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