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Motorized Bicycle General Discussion All topics regarding bicycles with engines.

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  #1  
Old 10-08-2016, 07:52 PM
wrenching4fun wrenching4fun is offline
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Join Date: Jun 2016
Location: North Carolina
Posts: 10
Default Hurricane Mathew Build

Didn't have anything to do while waiting out this storm, so I camped out in the garage for a while. Pulled the 66cc HT out of my Stiletto and threw in a 79 cc Predator I bought with a gift card my son gave me to Harbor Freight. Removed all of the extras including the governor and cowling. The engine went in quickly, and the Hilliard clutch was easy to fit, but it took 3 days to find a short in my tach light that was keeping my stator from driving my LED headlight and tail light. (shorting amperage straight to ground) All is good now and will be testing my gearing as soon as the streets dry off. The Hilliard has 10 teeth and my primary drive is an old moped sprocket with 40 teeth. The secondary on my jackshaft is a 10 and the sprocket on my wheel is a 36. Hoping for 45 or 50 MPH out of the gate. Could only get 40 with the Chinagirl. Can see why people like these Predator engines. They start on the first pull and they are easy to modify.
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  #2  
Old 10-09-2016, 01:46 AM
TheNecromancer13 TheNecromancer13 is offline
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Join Date: Jan 2015
Location: Portland, Oregon
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Default Re: Hurricane Mathew Build

No way you're going to hit 45 or 50 running a 14.4:1 gear ratio. I have a heavily modded 79cc predator and it only hits 40 with a 13.1:1 ratio.
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  #3  
Old 10-11-2016, 09:22 PM
wrenching4fun wrenching4fun is offline
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Default Re: Hurricane Mathew Build

Thanks for the encouragement, Necromancer. It was very helpful. Since you seem to know everything, maybe you can tell me what size capacitor I need to keep my LEDs from blinking at low rpm.
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  #4  
Old 10-12-2016, 12:40 AM
mat_man mat_man is offline
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Join Date: Jan 2011
Location: athens ga
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Default Re: Hurricane Mathew Build

Welcome W4F

Giant Stiletto looks great. Tons of space. Built in jackshaft.

I am only getting 30 MPH using your gearing with this:

Rawge's Mini Chopper jackshaft calc:
http://rawge.bravepages.com/minichoppers/jack.htm

(6000 RPM with 24" wheel)

With 45 MPH gearing you are going have pedal more to have a decent clutch life.

Wind resistance goes up with cubed root of speed.
But with such a long bike you could lay down to cheat the wind.

Best of luck.
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  #5  
Old 10-12-2016, 12:47 AM
TheNecromancer13 TheNecromancer13 is offline
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Location: Portland, Oregon
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Default Re: Hurricane Mathew Build

Quote:
Originally Posted by wrenching4fun View Post
Thanks for the encouragement, Necromancer. It was very helpful. Since you seem to know everything, maybe you can tell me what size capacitor I need to keep my LEDs from blinking at low rpm.
Unfortunately not, I'm pretty clueless when it comes to electrical stuff. I haven't even experimented with engine powered lighting at all.
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  #6  
Old 10-12-2016, 12:50 AM
mat_man mat_man is offline
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Location: athens ga
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Default Re: Hurricane Mathew Build

Your bike has a 7 speed freewheel I overlooked. Gearing looks perfect
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  #7  
Old 10-12-2016, 12:10 PM
wrenching4fun wrenching4fun is offline
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Join Date: Jun 2016
Location: North Carolina
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Default Re: Hurricane Mathew Build

Actually, Mat Man, I removed the freewheel to install the fatty on rear. Would like to figure out how to re-install. Here are some bad photos of the work so far.
Attached Images
File Type: jpg DSCN3421.JPG (650.4 KB, 39 views)
File Type: jpg DSCN3422.JPG (589.0 KB, 25 views)
File Type: jpg DSCN3423.JPG (635.1 KB, 24 views)
File Type: jpg DSCN3424.JPG (584.2 KB, 18 views)
File Type: jpg DSCN3425.JPG (658.6 KB, 21 views)
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  #8  
Old 10-12-2016, 12:14 PM
wrenching4fun wrenching4fun is offline
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Join Date: Jun 2016
Location: North Carolina
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Default Re: Hurricane Mathew Build

Last photo.
Attached Images
File Type: jpg DSCN3426.JPG (433.4 KB, 16 views)
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  #9  
Old 10-13-2016, 12:13 AM
mat_man mat_man is offline
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Join Date: Jan 2011
Location: athens ga
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Default Re: Hurricane Mathew Build

Wow! Great build on a bike made to be motorized.
I think you have room for a 212cc in that frame.

With your bike returned to the stock freewheel,
You will have the same function as a $150 Sick Bike Parts Shift Kit.

This is the great option for top speed for the 79cc.

This guys 79cc is getting 40mph with a SBP shift kit:
https://youtu.be/DZQxBofT_Mk?
4 stoke motorized bicycle 40MPH

You may have problems with the new NC registration and insurance laws.

Thanks for the great hi-res Pics.

Last edited by mat_man; 10-13-2016 at 12:33 AM.
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  #10  
Old 10-13-2016, 11:16 AM
wrenching4fun wrenching4fun is offline
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Join Date: Jun 2016
Location: North Carolina
Posts: 10
Default Re: Hurricane Mathew Build

I had to add an adapter to the OCC hub for a bolt-on sprocket, so will have to figure out how to re-adapt it for a freewheel. The threaded side of the hub holds another adapter for a brake disc. Might have to reverse and improvise. Does anyone know if they make four or five speed freewheels?
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