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Discussion Starter #1
Is there a general range of wheelbase for bikes based on a featherbed? I know it's a vague question and frankly I can't remember why it even occurred to me to ask...coulda been the maker's mark last night.....
 

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54 inches, or less makes, for a nice flick-able f-bed

this means if you put anything like say...... an oil bag triumph swing-arm one one so you can us something other than a ten speed bicycle width rear tire... and of course be rid of those miserable "silent-bloc" bushing excuses

you have to shorten the swing-arm

plenty of them out there with wheel bases 60" or more

can't even imagine why
 

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Discussion Starter #3
Perect! Thanks for the info..
 

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and if you want pix...... I have plenty

including a flipped and shortened oil bag arm swinging from a one off machined axle using timken taper bearings fully adjustable for preload and side to side

I think I may also have pix of one with a XS650 swing arm wiggling about on one with nearly a 60 inch wheelbase too


seems to me it would be nifty to derake one and shorten a swingarm even more to come up with something around 52 inches

are you doing one? be sure and fab up a for real headstock brace if you plan on punishing it

one here has a four inch tubular headstock brace that carries the engine oil very well
 

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HackA,
With the right unit construction engine, would it be possible to use a long swing arm and just move the pivot farther forward to shorten the wheel base and still keep a longer swing arm?

Ken
 

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Most unit construction engines I've seen fitted to fbeds appear to need something that drastic sounding

a unit triumph for example is about 16" OAL

room for nearly a ten pound ham in the engine cradle once a unit triumph lump is in place

I would guess that relocating the swing arm pivot would be very doable but I'd say the easiest way to do it, that didn't look like a hat full of open azz, would be to section it out of the duplex cradle section that the engine/tranny goes into

do you want some numbers as far as stock swing arm lengths and others?

I'm thinking that off the top of my head the oil bag tri swing arm is about 1.5" longer than the stock fbed unit

that fbed swing arm is pathetic

are you thinking about a 'long' swing arm for hill climbing, drag racing, or just overall more straight line stability?

one of the neat things about the fbed is that it's one of the few stiff vintage frames you can easily obtain GP unforgivingly fast steering wheelbases

sorry for the runon and hope you can decipher it

a neat fbed with a compact unit engine that may still be out there to be found on the net is Greg Sommerton's (I think I spelled that correctly but if not, sorry Greg) typ15 jawa 500

worth doing some google image searches for

I really want one of those engines with the bevel gears but would settle for a spur engine
 

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yeah man.... that particular typ15 is a bevel engine and he did a nice job of laying it in the frame without it looking like 'where's the rest of it?'
 

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but I can't imagine how he rides it, being as tall as he is, with the pegs where they are and clip ons so very low

I'm not sure I could for very long but maybe the camera angle makes him appear taller
 

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Discussion Starter #10
That's a cool bike
 

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Why would anyone want to hack up the best handling (and best looking) tubular frame ever made? If it can get Mike Hailwood's butt around the Isle of Man at an average of over 100mph why is there a need to change it?
 

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Forgive me, but I find unit Triumph motors to be much more attractive than pre-units. Actually one of the prettiest motors I can think of, even though not considered very traditional. I would never even consider a pre-unit in a featherbed, regardless of what all the purists say. In fact, I think a Hinckley triple would be pretty cool in a featherbed.
 

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Fortunately a featherbed is big enough to take just about any engine. But I have to say that featherbeds tend to swallow up unit motors. A Hinckley triple in a featherbed is something I would like to see. But I should talk. I've got a skinny little Weslake in mine. Its about the same size as a C15. Big fairings work wonders.
 
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