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  1. #1

    Default Sportster fork tubes

    So I just picked up this 99 sportster and Iím looking to extend the fork tubes on it. Previous owner who I bought it from didnít install anything (had it for about a year/never rode) and he wasnít sure if the original owner before him installed a lowering kit. My question is, if I want to extend it, other than taking everything apart how do I figure out if it was lowered? If it was how can I tell if it was the springs that were lowered or damper rods?

    Here is a pic of it as well.

    Click image for larger version. 

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  2. #2
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    Owners are lazy and usually cut or replace the springs since pulling apart the forks is too much like work or they don't wanna pay the fork teardown labor. You can restore whatever ride height they took away with PVC spring spacers.

    Jack up the bike to see max fork length with the tube and rod combo you have since the unloaded fork will fully extend.

    It's easy to remove the caps (good time to change fork oil) then remove and inspect springs for crude cut marks, and while you have the bike on a jack the forks will be fully extended so you'll know that measurement. The Motion Pro cap nut socket is about 20 bucks. Otherwise a 6-point socket that fits will do but the shallow socket is worth buying.

    http://sportsterpedia.com/doku.php/techtalk:evo:susp01

    http://www.chopcult.com/forum/showthread.php?t=49444 How I compress fork springs cheep.

    Pic shows how I convert common pantograph jacks for bike use by welding three pieces of angle. (I like the jacks off GM trucks best and most have a nut instead of a loop like the example car jack, but I now cut the loops off and weld on a socket so I can use a cordless impact for speed). Hunk of scrap Sporty frame was handy so I placed it there to demonstrate. It's handy to have lots of jacks,stands and blocking so you can leave a bike in the air while doing other work, and screw-driven jacks don't bleed down.

    Trackerdie damper rods get you a few inches more suspension travel (the best way to gain length). I bought a set for more travel on my FXR front end (they're longer than those long FXR rods) and they're well made. I would fit those first then if you want ordinary extension (there being no more travel increasing options due to slider/tube overlap limits) you can run longer tubes too. They're longer than any stock 39mm HD rod.

    Forks are easy to disassemble. I often do one side at a time leaving the opposite to hold the triple clamps in place.

    The way I usually remove damper rods is using a long 3/8" drive hex bit so I can quickly break them loose with an impact. If I don't have a hex bit handy I chop off an L-shaped key and use the long section in a six point socket. If you remove the front wheel then break the damper rod bolts loose with the forks installed the springs will hold tension on the rods. When installing the bolts finger tighten them (never start a threaded fastener with an impact unless it's a special case).

    Since you're gonna disassemble the forks anyway if you want to extend them a little or a lot, I'd pull the side without the brake caliper apart because that's less work (pull wheel, fender etc then assembly) to see what I have and measure removed tube and damper rod. If I had one of mine torn down it would get the Trackerdie dampers regardless so I'd have them and a seal kit in hand. I'd reassemble the fork leg with the new damper, compare lengths, take pic of difference for reference then do the opposite side. I'd measure the bare fork tube while apart and (styling is in the eye of the beholder) order longer tubes if you feel like it.
    Attached Thumbnails Attached Thumbnails sporty jack3.jpg  

  3. #3

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    Yeah TC bro’s sells a +6 extended fork tube kit that I wanted to pick up but before I purchased that I wanted to figure out if I need to purchase a new spring as well. Or can I use the springs in it and still run the new tubes? Probably would need a longer pvc spacer if the springs are cut down. Or else it won’t really be +6 over. Realistically I need to just tear down everything and inspect it myself. That site you posted has the measurement for the stock max fork length? Also, Good tips though with the caulk gun and the jack. My younger brother is a welder and I can have him weld up something like that.

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    There's no way to know if the spring's been cut down without seeing it but since you can always add more PVC (and will need to space anyway for the extra tube length) best bet is get to work on it since you can always run the springs you have.

    Tear it down and see what you have. BTW you can also fab the same style jack attachment for a floor jack.
    Last edited by farmall; 05-14-2020 at 8:10 PM.

  5. #5

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    Yeah that’s what I figured I’m going to have to do. Might try Changing the damper rods first and see how that feels and if I want it longer I’ll swap the tubes. If only I had a spare car jack I’d make my own lift.

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    i have a 92 hugger w tc bros 6 overs installed. it was pretty easy to install. not sure if this matters but the huggers have -2 fork tubes and i just put the pvc spacer and stock spring in and it runs and rides fine. if you have the funds might be worth it to replace the springs since ur gonna have em out anyway i think progressive makes afttermarket progressively coiled springs for like 100 bucks. im a broke ass college kid so i just used the stock springs lol. i really like the 6 over stance and the tc bros tubes are good quality. can corner harder too without having pegs scraping on every turn lol. good luck with it man

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    Quote Originally Posted by EightythreeD View Post
    Yeah that’s what I figured I’m going to have to do. Might try Changing the damper rods first and see how that feels and if I want it longer I’ll swap the tubes. If only I had a spare car jack I’d make my own lift.
    The damper rods are a performance upgrade so doing that first is the smart choice.

    Local salvage yards would likely let a good jack (truck jacks off Tahoes, Silverados etc) go for ~20 bucks.

    Harbor Freight have ones similar (probably made by the same subcontractor) jacks to the car jack in my pic for ~$24. https://www.harborfreight.com/1-1-2-...ack-66907.html

    I weld sockets to all my jacks (I collected a shitload when I had free salvage yard access) so I can raise them with my impact drivers and now I rarely use my floor jack for truck work since the same setup for lifting motorcycles fits well under control arms and other truck parts. They kick ass for salvage work too since they fit in a backpack.

    I also collect wooden blocks (4x4 and larger) which are handy on their own and can support pantograph jacks if required.

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