4 stroke on a kids BMX? Hell yeah!

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I saw this BMX laying around in my buddies yard.. "can I have it and put an engine on?" "you can do to this bike whatever you want"
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20" wheels

I used round steel from ace hardware, flattened the ends and drilled a hole for a screw. Then I was able to mount the engine mount over the rear wheel. A twisted piece of flat steel prevents back and forth movement. That one is slotted so I'm able to move things around later on
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This bike has massive steel drop outs so no problem drilling through them.



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Top speed at 6800RPM is 25mph. Hop on, pull start, give it some throttle and go. It feels zippy and easy to move because it's so small.

Just yesterday I replaced the 100t pulley with a 80t pulley.
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my beer holder and GPS speedometer

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I built my own extra long throttle cable out of an old brake cable

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I saw this BMX laying around in my buddies yard.. "can I have it and put an engine on?" "you can do to this bike whatever you want"
View attachment 172299
20" wheels

I used round steel from ace hardware, flattened the ends and drilled a hole for a screw. Then I was able to mount the engine mount over the rear wheel. A twisted piece of flat steel prevents back and forth movement. That one is slotted so I'm able to move things around later on
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This bike has massive steel drop outs so no problem drilling through them.



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Top speed at 6800RPM is 25mph. Hop on, pull start, give it some throttle and go. It feels zippy and easy to move because it's so small.

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my beer holder and GPS speedometer

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I built my own extra long throttle cable out of an old brake cable

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What size wheels; is the belt drive 5:1; what size sprockets???
 
Your GPS speedometer is off or you aren't turning 6800 rpm. Get a bicycle computer. I didn't see a tachometer on your bike. You should get one with an hour counter. They are inexpensive the hour counter is good for maintaining a maintenance schedule

(6,800×20×π)÷(1,056×4×(36÷10)=28.0971565188
 
Your GPS speedometer is off or you aren't turning 6800 rpm. Get a bicycle computer. I didn't see a tachometer on your bike. You should get one with an hour counter. They are inexpensive the hour counter is good for maintaining a maintenance schedule

(6,800×20×π)÷(1,056×4×(36÷10)=28.0971565188
Oh I just said 25, it’s my own limit since I don’t have a rev limiter. You’re right, at exact 6800rpm it is a bit faster. My gps speedometer is accurate, tested.
I also use it as an odometer, trip meter, fuel gauge and run time. Link https://www.amazon.com/dp/B088JVVS1Z/ref=cm_sw_r_cp_api_i_0XJJECVHXRR3MHRQWTJV?_encoding=UTF8&psc=1

Edit: @Sidewinder Jerry Oh and thanks with the tip for the tachometer! I actually use them on my commuter bikes. I hooked one up to this baby bike just to see and test but then removed it. I’ll do my oil changes per miles on this bike, the bike is just for fun. Most parts and the engine I had laying around after upgrading to Grubee on my other bikes
 
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Oh I just said 25, it’s my own limit since I don’t have a rev limiter. You’re right, at exact 6800rpm it is a bit faster. My gps speedometer is accurate, tested.
I also use it as an odometer, trip meter, fuel gauge and run time. Link https://www.amazon.com/dp/B088JVVS1Z/ref=cm_sw_r_cp_api_i_0XJJECVHXRR3MHRQWTJV?_encoding=UTF8&psc=1
These engines are good up to 7500 rpm. With a tachometer you can keep your rpm in the safe range without a rev limiter. Basically 28 mph on level ground and throttle back once you hit 31 mph down hill.
 
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These engines are good up to 7500 rpm. With a tachometer you can keep your rpm in the safe range without a rev limiter. Basically 28 mph on level ground and throttle back once you hit 31 mph down hill.
Oh that’s good to know! I edited my other post, I hooked up one just to see my range 👍🏻

Beer holder, :LOL: Lets us know when ya get pulled over
Haven’t had a problem yet, you can’t really see it’s beer when it’s in there. I built it from a tomato can with a Koozie inserted 😂
 
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