20 inch bicycle build

GoldenMotor.com

JerryAssburger

Active Member
Mar 11, 2017
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Salem Oregon
So far the most difficult part is the chain and sprockets clearance. With a small frame there’s not a lot of options. I used a 32 tooth rear and if I did it again I would get a 28 just to get a little more room for routing.
Yeah, a 28T would net you 31 MPH @6000 RPM, so it would be do-able. This really looks great. The tensioner is genius- it'll be a LOT harder for that thing to ever rotate into the spokes, God Forbid.
I think I wanna STEAL that idea from you and try it on my Cranbrook!
 
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Larry Trotter

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Nov 26, 2017
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It’s easy to make. I just cut it in the right place and welded it on the side. It’s really rigid this way and you can bend it to align it with the chain. I got the throttle and clutch cables installed so now just the brakes and some chain adjusters to keep the rear axel in place.
 
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Larry Trotter

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Nov 26, 2017
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Got all the cables hooked up and routed. Here’s a little neatness clue, if you are careful you can put the end of the clutch cable inside the return spring and clean up the end of that cable. 2178423A-C484-4C9E-B73B-62B175716134.jpeg
 

Larry Trotter

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Nov 26, 2017
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Not much today. Made up some axel mount chain tensioners from pieces I had sitting around and also ran an 1/8 inch npt pipe tap into the fuel tank so I can use a granger ball valve for the fuel. I have only had grief with every factory fuel valve I have had so I will try this. The tank is tapped with a 10mm by 1 straight bolt thread and a 1/8 pipe is a taper about .018 larger and a pitch of .94mm so very close. Tap went in nicely and cleaned up about 5 threads totally and the rest partly. I will take pictures Monday when I get the valve and fittings.
 

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Larry Trotter

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Nov 26, 2017
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Picked up the 1/8 npt ball valve today. Already ran in a pipe tap and cleaned up the threads. The tap was $6.75 delivered from eBay and the ball valve was $6.51 from Granger. I will see how it seals up but it get tight with a couple of threads still showing so I think things will be good.
 

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Larry Trotter

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Nov 26, 2017
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Well I put some gas in it and it started right up. Only two things were needed, I had to slack off the throttle cable some to get the idle down and it’s probably running a little rich because it’s 4 stroking at about 25mph. This thing is really a fun ride and lots smoother than my 27 inch.
 

Larry Trotter

Well-Known Member
Nov 26, 2017
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Finished everything off a installed and calibrated a speedometer. Hit 30 mph pretty easily so I really don’t need more than that. One last little mod is using the front motor mount adapter to support the bottom of the muffler. Pretty easy with a little plumbers metal strap. That pretty much wrappes it up.
 
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Larry Trotter

Well-Known Member
Nov 26, 2017
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Another little observation. Yesterday I was riding and had forgotten to turn on the fuel. I switched it on while still rolling and when the engine fired up this short little thing pulled a pretty big wheel stand. So be careful it can surprise you lots.