Twin Carb Softtail

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Theon

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Jan 20, 2014
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This is one of my current Builds.
It started as an old girls comfort bike I got from the dump.
The frame has been stretched a couple of inches, raked a fraction, and made to fit a China girl.
Please Help with photo upload this one seems a fluke!
 

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GearNut

Active Member
Aug 19, 2009
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When I read the title of the thread, I thought I was going to see a Harley-Davidson.

You did an awesome job of re-purposing that dump find into a great looking motorized bicycle!
 

Theon

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Jan 20, 2014
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Hay cheers guys,
I'm still figuring out the photo thing???
I have another build that I'm just figuring out and taking a few photos as I go,
I't's a drift trike, but has 6 wheels?
And eventualy will be a 3 wheel tilter.
That's Motorized Bicycle project No.5.
No. 4 consists of a tadpole FTC tilter running a warm pocket bike motor with 3 gears..
The 'Phantom', is No 4, a 24" racer which is still going through final tuning, and does 70Kph with a reasonable amount of low down and a Flip Flop hub on the back for different tracks.
The 'Softtail' is No. 3, with a warm 38mm unbalanced crank engine, with stuffed cases, reshaped head including Still Decomp' valve, 7 speed shift kit and twin pocket bike carbs (just for Bling!).
No 2. The 'Rat Rod Mountain Goat' was a test bed for the Softtails Drive train, And is now awaiting being turned in to an alloy 26" Racer, when I find the right motor for it.
No. 1. is the 'Old Raleigh', which is where this all started, and currently will hold 80Kph, but I don't know how long for!
I'll try and get some better Photos up, and would really appreciate the advice.
 

Theon

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Jan 20, 2014
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Theon

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Jan 20, 2014
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Excellent, Thankyou.
I love taking photo's and documenting my work,
I had a falling out with Sc***ing R** Forum 'King', and looking for a new outlet to share a little creativity without the 'Bad Humor' and 'secrets' and an Edit Button that Works!
 

Theon

New Member
Jan 20, 2014
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Got the Softtail tuned in a little better today, running .5mm main jets, and I've got the neddles up a notch on the clips from middle, it's a little rich while cold, but runs nice once warm, Idles beautifully and has a slightly darker than ideal plug. I will experiment with lifting the clips on the needles to the upper notch, one at a time, but think I'm pretty close. Besides I plan to run my bikes on an Av Gas Mix once I get them all sorted and running nice.
The motor is nothing special, A cheap 'GT5' with 38mm stroke and 'weird' Piston and rod.
It has awful Vibrations at 'moderate' revs. and needs to be 'detuned'. However I have over notched the piston to suit the 'lifted' and 'strange' barrel that came from a different motor! and can't find a new GT5 piston in OZ!
So at the moment see is lacking in both top end and bottom end!
The motor was built to be fast and is match ported, stuffed cases, and has a decomp valve in the head, but just Vibrates too much!
I'm considering Buying a balanced crank for her but built this bike to cruise on, and looking for low down grunt, So I need a new piston and she's getting a detune. Was also considering a reed valve, and started making my own but that deserves it's own thread.
The Shift Kit was a 'lemon' and for $99 each, I got two.
But after much messing around It works, But not near as smooth as a single BMX chain to a properly 'trued' Rag Joint.
Some better sprockets are probably all It needs though.
I took a close up of the rear end, which works well and is almost 'invisable' in true HD Softail style.
The pullstart is fantastic on this bike as the combination of high compression and 'weird' back gearing, was bending the cranks, hence the decop valve, which is no longer 'necessary' but makes the pull cord last a lot longer.
The Tank needs a Coat of Paint, But I like the Rat rod look for her.


 

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GearNut

Active Member
Aug 19, 2009
5,104
11
38
San Diego, Kaliforgnia
Wow! Your bike looks great! I like the way your dual carbs look.
I now see how the rear suspension works, at least from the shock side. How do you have the pivot set up?

Using rubber between the engine mounts and frame tubing has been known to increase the percieved vibration. It helps with the high frequency buzz felt in the handlebars, but you feel it more in the frame. Also it has been blamed for more broken mount studs than any other form of mounting... ever.
 

Theon

New Member
Jan 20, 2014
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FNQ Australia
This set of cases are wide mouth, originally I planed to build a new motor for this bike, with narrow mouth cases, but ended up throwing this Pig motor in for now, hence the rubber.
This motor wasn't good enough for the bike I wanted it for. And am still considering which motor to try next.
Iv'e been lucky with only 2 cranks out of 4! but the two good ones are rippers.
The engine did vibrate through the bars more when it was solid mounted, but feels a little better this way.
The swing arm is original. and pivots just behind the cranks, it rides nice.
 

Theon

New Member
Jan 20, 2014
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FNQ Australia
My 4th crank has a brass big end and havn't tried it yet, but am tempted to swap it in to these cases, to see if it's any better, otherwise thought of taking the GT5 crank in to get balanced? Still the shift kit is happiest at lower revs so might just detune her with a new piston and a spare stock '38mm' barrel I have here. With the gears she cruises at low revs and climbs anything, so may not be chasing revs on this motor?
My 9500 Rpm motor is an old Rocksolid crank, and after lightening the piston I lifted the Vibration point from just above 8500 RPM to just above 9000. So I don't do 9500 on her to often! and have been thinking of adding an inch or so to the header to bring my powerband down a 1000 RPM or so.
But this bike I just wan't to put around on, It don't have the same cornering 'feel' as my others.