52cc Predator Auger Powered X-Games FS20 BMX

16v4nrbrgr

16v4nrbrgr

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As some of you guys who listen to my ramblings might know, I got an HF auger motor for a good price recently. In search of the perfect frame for it, I found this at Walmart and ordered it. This week when the bike gets here I'm going to motorize it and it should look like above.

If anybody would like an engine mount after I get a final design and price, I will be selling them and would consider doing whole bikes for labor compensation for the construction of a whole bike locally.

With the gearing of the trans to the rear wheel 1:1 the bike will go 18, so I will overdrive it to about 30 mph top speed with a larger motor sprocket.

The Engine is 52cc, rated at 1.5hp, others rate it at 2.5 so I think with a expansion chamber 3 is possible. The trans is 33:1 approximately and uses heavy weight gear oil for the ring and pinion.
 

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I scored a pocketbike pipe for $20 off Ebay from gopedfanatic. :)
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I'm thinking I'm going to use this project as the test run for the plasma, and make the mount out of steel 3/16" plate.

The bike is suppedly on its way and will arrive by wednesday. I gotta finish up my OCC so I can hit this full force!
 
It is, but using a chain is much better in the long run and mounting the motor down low means the bike will remain balanced and agile like BMX should be. The cleanliness of the tires won't affect performance so wet roads and dirt and mud will be great fun not lame like a on a friction drive.

I thought about a rack mount but the high GC was the deciding factor against it in this case since the motor looks like it will work well bottom mounted.
 
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Most definetly following this! Looks like my speed. Could it be mounted in frame? With some wide pedals if need be?
 
If it works out in 3d like I've mocked up with a X-games solid crankset I have from another BMX, it will work just like the picture above with the stock crankset except the muffler will be on the other side, the carb is actually on the right side. BMX wheels are usually threaded on both sides so I don't imagine the left drivetrain to be difficult, and I'm gonna just use BMX chain to use up all of the chain I have in boxes everywhere.
 
I only ask about in frame because I'd like to use this Pacific Sabotage bmx/cruiser I've had for a few years now. Has done everything I've asked of it.
 

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That's an awesome BMX!

If you give me a good drawing with dimensions I could make something for you. :) It you think you're up to the task of reverse drafting your bike I can make something that will fit like a glove. Of course I can design in wiggle room but accuracy is always very important.
 
Oh sh!t, you just got too smart for me!
I can give you an accurate drawing the of inside frame dimensions with tube diameters but reverse drafting? Yup,lost me sir. But if you work with me a little I can provide any and all info necessary for a 20" in-frame/under-frame mount.


Some items/ideas:

I can put in a wide crank if need be. Or a short one-peice and 30T chainring.

And I could get a Staton rear wheel. They sell a left-hand freewheel that SBP's chainrings should bolt to.

Or a disc brake rear wheel from Chopperus.

If a big sprocket is necessary for either wheel,I would go with King's Sales. If it needs a 15T-19T,Ben's Cycles sells VeloSolo disc cogs for 1/8" and "3/32" chain.
 
I didn't wanna call it "reverse engineering" lol, I just need the dimensions of the area where you want the motor mount and chain-line offset distance from center. These tiny motors are limited on mounting points witch fortunately the transmission casing makes up for.

Please PM me about your own BMX and I should be able to make something for you.

I can't wait to get this bike delivered this week!

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I got the bike today and put it together quickly and went for a ride. One neat thing you can't see in the Walmart pics is that the handlebars are reinforced with an "X" where the chin pad would go. I wrenched it around the block and did a bunch of bunny hops and I'm confident that this is a very strong steel frame.

Overall, the bike is really nice for $110 total, I'm totally happy with it as a bicycle, so should be great fun motorized.
 
Yeah I can't wait, thinking pegs on this so I can rip on it right away no matter my license status. Maybe get some Goped stickers off Ebay, lol.

I hope to get going on this next week, need a sprocket, and a decision as to the material to make the mount out of, thinking welded steel. I'd like to make a simple mount that I could replicate for under $100 so anyone could make one for themselves. I have a plasma cutter now so thick plate is no problem.
 
I'll get some pics and progress up soon, after I start the OCC, I'll start the motor mount fabrication.

Right now I'm considering breaking in the motor as an auger to till up my little yard which is overgrown with weeds. That's what the warranty covers so might as well, there aren't many rocks because the previous tenant was a gardener.
 
Today I ordered a Staton 7/8 ID freewheel adapter and a Crossfire freewheel for a five hole 27t to go to a tack welded to the hub Sturmey 16t on the rear through KMC BMX chain.

That will take the 33:1 from the output and make it 19.6:1 for approximately a 30 mph top speed. I have a crossfire 16t that can be used to gear it for mountain climbing at 33:1 but I think this motor should have enough grunt geared higher.
 
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Recieved the stuff from Staton today, and picked up some exhaust clamps to use to clamp the motor mount to the frame. Got some stainless u bolts too, look a bit nicer.
 
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