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Old 10-04-2005, 04:58 PM   #1
el_Poderoso OP
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Shortening fork tubes?

I am in the process of lowering my 92 bumblebee GS by 1". The rear shock was easy. Lowering the forks is another matter. If you try to lower the tubes in the triple tree, you hit the handle bars or the edge of the instrument panelon hard turns. Custom forks (Forking by Frank) is an option, but I am wondering if there are any machine shop types who could cut 1" from the stock fork tubes and rethread/machine as needed.
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Old 10-04-2005, 06:25 PM   #2
Wheedle
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IMHO.... take it for what its worth, the best option is to shorten the main springs and either space up or get longer top-out springs to match the lenght you took out of the main springs. If you dont do this, your moving the tire with the suspension bottomed out 1 inch closer to hitting whatever is nearby.
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Old 10-04-2005, 07:12 PM   #3
datchew
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just because i'm curious, why are you trying to lower it?

if it's a height issue, would a different seat perhaps help to get your feet closer to the ground?
i think i'd try a few other things before i did heavy modifications for a measley inch.
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Old 10-04-2005, 09:55 PM   #4
woody's wheel works
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try loadedagain

Quote:
Originally Posted by el_Poderoso
I am in the process of lowering my 92 bumblebee GS by 1". The rear shock was easy. Lowering the forks is another matter. If you try to lower the tubes in the triple tree, you hit the handle bars or the edge of the instrument panelon hard turns. Custom forks (Forking by Frank) is an option, but I am wondering if there are any machine shop types who could cut 1" from the stock fork tubes and rethread/machine as needed.
i think loadedagain has a machine shop that could do that,,pm him!!
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Old 10-05-2005, 12:30 AM   #5
Paragon
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Bar risers - after you have dropped the top yolk
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Old 10-05-2005, 01:14 AM   #6
sharkey
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Quote:
Originally Posted by el_Poderoso
I am in the process of lowering my 92 bumblebee GS by 1". The rear shock was easy. Lowering the forks is another matter. If you try to lower the tubes in the triple tree, you hit the handle bars or the edge of the instrument panelon hard turns.
I'd add 1" bar risers and take a dremel to the instrument panel then!
If that makes the bars too high for you, use flatter profile bars. Alternatively, just take preload out of the springs until the static sag
is 1" more! Sure. you lose some travel but you'd lose that anyway.

Dare I ask why? If it's just that you're a bit ... vertically challenged ...
you'll get more improvement per dollar by thinning the seat padding
out a bit. Also, you won't ruin your ground clearance that way.

-----sharks
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Old 10-05-2005, 11:59 AM   #7
datchew
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Quote:
Originally Posted by sharkey
I'd add 1" bar risers and take a dremel to the instrument panel then!
If that makes the bars too high for you, use flatter profile bars. Alternatively, just take preload out of the springs until the static sag
is 1" more! Sure. you lose some travel but you'd lose that anyway.

Dare I ask why? If it's just that you're a bit ... vertically challenged ...
you'll get more improvement per dollar by thinning the seat padding
out a bit. Also, you won't ruin your ground clearance that way.

-----sharks
he he he.
why do i get the feeling you didn't read any of the previous posts?

Hey! great minds think alike!
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Old 10-05-2005, 12:10 PM   #8
Paragon
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That is not very "politically correct" these day, old boy

Poor chap
We British are far more discreet
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Old 10-05-2005, 03:17 PM   #9
sharkey
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Quote:
Originally Posted by datchew
he he he.
why do i get the feeling you didn't read any of the previous posts?
I'm just agreeing with them! It'd be insane to spend the money required
to machine the stanchions when there's easier ways. Maybe I should add: buy some platform shoes!

Quote:
Hey! great minds think alike!
... and fools seldom differ.

-----sharks
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Old 10-05-2005, 04:05 PM   #10
Frank Warner
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It would be far simpler (and cheaper and easier to undo) to shorten the damper rod inside the fork tubes. Buyt a new rod and shorten that - that way you can easily go back.
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Old 10-05-2005, 06:32 PM   #11
datchew
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Quote:
Originally Posted by sharkey
I'm just agreeing with them! It'd be insane to spend the money required
to machine the stanchions when there's easier ways. Maybe I should add: buy some platform shoes!



... and fools seldom differ.

-----sharks
he he he. funny thing is that i was going to mention platform shoes as well.
(perhaps that's not pc either but then, who cares)

if i lived closer i'd buy you a VB. mmmm... VB.... been tooooo long since my last taste of the green slime.
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Old 10-05-2005, 08:03 PM   #12
sharkey
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Quote:
Originally Posted by datchew
if i lived closer i'd buy you a VB. mmmm... VB.... been tooooo long since my last taste of the green slime.
Eww. Very nasty. Try the Coopers next time you're on this side of the planet.

-----sharks (just put a new Bitubo CZE shockie on the bike,
better go try it out ...)
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Old 10-05-2005, 08:50 PM   #13
el_Poderoso OP
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Going to try the Poverty Way First

Quote:
Originally Posted by sharkey
I'd add 1" bar risers and take a dremel to the instrument panel then If that makes the bars too high for you, use flatter profile bars. Alternatively, just take preload out of the springs until the static sag
is 1" more! Sure. you lose some travel but you'd lose that anyway.
Good tip. The GS has a plastic spacer on top, so I think I will try a shorter spacer by 1/2 and see if that makes the bike less "chopperlike." A very cheap and reversible solution. If it works well, I'll look for a way to make it permanent. I want the end result to be professional looking as well as functional.

Alternately, I am an auto body repairman, so I could easily reshape the dash and make it look trick, so 1" risers and raising the shock is an option. I plan on adding progressive springs to firm up the front suspension to match the feel of the very firm Works Performance rear shock. The Works shock is shorter, but doesn't bottom out like the stock unit did.

I am a short guy with a 28" inseam and weigh only 150lbs. All dual sports are tall in the saddle, so I have shortened the saddle and that helped a little.

My theory: A typical 200+ pound GS rider would probably eat up more (stock) suspension travel just by sitting down on the saddle than my stiffer but shorter suspension.

I ride 85% street, including commuting, but I do ride dirt roads a half dozen times a year. Usually nothing too extreme.
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Old 10-05-2005, 10:49 PM   #14
Donkey Hotey
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Some thoughts on this:

1) Forking by Frank can get you tubes for just about any bike ever made on earth--except the old Airhead GS. I called and heard some excuse about that tubing being an odd dimension. Whatever it was, they could not help me in my search for replacement tubes.

2) Remachining may or may not work but even if it does, it will cut through the chrome (which may peel) AND you'll need to shorten the springs anyway. As others have already suggested, your easiest route is to simply take out 1" of preload spacing. The next easiest route is to cut 1" off the top of each spring. What's the difference? Cutting the preload spacer changes your static sag. Cutting the spring actually stiffens the spring slightly AND lowers it (fewer coils with the same wire diameter = higher rate).

3) If you cut the fork, your centerstand will be too long. With short forks, it could rock forward and right off the stand. Less static ride height might help you without getting into other problems.

With your light weight, I'd opt for just lowering the preload in the back and cutting or removing the front preload spacers. I've read many times that plastic irrigation pipe is often usable for custom preload spacers. In my experience, I've not been able to match up the spring diameters I needed. They're a quick job if you know somebody with a lathe and some aluminum tubing.
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Old 10-10-2005, 08:36 PM   #15
el_Poderoso OP
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LOWRIDER R100GS: Mission accomplished

Quote:
Originally Posted by GregCifu
With your light weight, I'd opt for just lowering the preload in the back and cutting or removing the front preload spacers.
I cut the preload on the front fork spacers by 1" and installed a Progressive spring. This spring would be a little firm for my lighter weight, but with no preload, the new fork is nice and soft on small bumps but fends off potholes, speedbumps and similiar urban obstacles when it gets hammered.

Now the front performs similar to the shortened Works rear shock. YES, I had to shorten the centerstand too. With 1.25" removed, the ends of the centerstand tuck in neatly behind the front pegs with the centerstand up.

Bottom line is a firmer ride, no bottoming out and I can plant the front soles of my boots (not platforms) firmly on the pavement. This is much better than being all tippy-toed in traffic.

The bike looks normal and handles awesome. This operation has also decreased the too-steep angle of the GS driveshaft to something closer to the standard R100, which "may" result in longer driveshaft life.

Pics available if you are a shorty-type and you are interested in creating a lowrider GS of your own. If I want to switch back, I'll have to have my rear shock lengthened, buy new spacer tubes and find a used centerstand.
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