Sportster fork lowering questions, pics inside.

[dethtrap]

I have my stock 02 sporty 39mm forks disassembled and the springs out. I am looking to lower the front end about 3-4". After doing some research online I have decide to cut the springs and use pvc spacers.

From what I have read the coils should be cut from the end where the coils or more spaced out (the left side in the pic). A piece of pvc should be cut to match the height of the cut of piece of coil and inserted down in fork tube. The spring should then be inserted back into the tube with the tighter coils resting on top of the pvc and the cut end coming out the top of the tube.

My questions are, first does this sound correct? Second how much should I cut off to get about 3-4 inches? Lastly, should I use a heavier weight oil in the fork tubes and if so what weight? Thanks in advance for any help.

[brooklynbomber]

Why not do an actual lowering kit?

Licks sells front end lowering kits that are engineered, just my $.02

Lowering Kit

[frazzler]

over the damper tube.You need to tear your forks completly down.the allen that holds your lower legs to the damper should be a 7mm allen if i remember right cut your spacer the length you want it lowered . I used a piece of copper pipe that I got at lowes. your spacer needs to be big enough to slide over the damper and be small enough so the spring can but up against the spacer and not slide over it (the spacer).I dropped the front of a 77 4 inches I only cut 2inchs of the spring in your pic to give me some preload (it makes it harder to bottom out if you hit a pothole)but it does make it a bitch to get your fork caps back on.if you have never tore your forks completly down find a pdf online and look at the exploded diag. and it will make it so much simpler if you cant find one I will try to scan the page for you when I get off work this eve.
all props go to Jakemon

[masterblaster]

i just cut 3" out of my top tube.. then you dont have to mess with the bottom end..

[TheSandman]

I think your suppose to cut off the bottom of the coils where they are tighter. Those are considered dead springs and shouldn't affect spring compression much if at all.

[BadMonkeyMW]

The free advice on this one is worth every penny.

[frazzler]

this is damn near step for step how I did mine.It all depends on how much time you want to invest vers. price of a lowering kit .I didnt make a tool for breaking loose the allen bolt that goes to the damper.I reassembled the fork tube it puts pressure on the damper and helps hold the damper and keep it from turning and broke the allen bolt loose
http://www.xs650chopper.com/2009/06/...k-garage-tech/

[masterblaster]

ok i see what youre talking about.. im a dumbass and i was told to cut the top tubes down which i did.. it will still work i just have to cut the springs down now.. i honestly dont know shit about the front end.. i have a friend working on it.. thanks for the tips..

[BillyT]

Pull the springs out, cut them, drop them back in. End of story. My bike rides awesome, no issues at all.



And yes, the coils that are close together are dead coils. Cut those. They do nothing but set ride height. They are fully compressed when the bike is sitting on the ground.

If you or you bike are heavy, you will prolly have to do the spacers to get some preload back. But in my real world experience, with a 465ish pound bike with a 180 pound rider its been a non issue.

Also, the way I got mine to sit where I wanted, was to have the bike on the stand with the spring caps off. Lower the stand to set the forks where you want them, then cut the spring about an inch from the top of the tube. It'll be a littl taller when you aren't sitting on it, but just right when you ride it.

[BillyT]

ha! Month old thread is a month old...

[TheSandman]

So you just cut the spring and dropped it back in and it rides awesome? With no preload on the springs, I would think that it would be really soft.

Putting the spacer on the bottom and cutting the top spring would still allow you preload the spring.

[BillyT]

yeah, seems fine. Like I said, though, depending on how heavy the rider or the bike is, you might get different results.

I can't make the thing bottom out, try as I might... And I haven't felt it bottom out on the road for sure.

[ironhed]

im in the process of doing this now shaving and lowering forks ect

maybe this is a stupid question but what's the reason for useing PVC as the spacer ??

[ironhed]

also anyone no how much you can machine down 39mm fork legs ??

[masterblaster]

if i were you i woudnt take too much of of any forks.. as far as shaving them.. theyre already pretty thin and they are alum.. back to what i was talking about.. its not as easy as just cutting the springs.. i cut my top tubes and its working out fine.. not that i have that much travel anyway but i didnt want to limit myself.. i wanted it 3 under so i cut 2.5 off the top tubes and had them truned down and tapped.. ill take the other .5 out of the springs to get it right where i want it.. it should be done in the next week or so ill post pics when its all together..

[BillyT]

All the spacer does is keep the tube from extending all the way out. The only pressure that is on it is from how much preload you have. PVC is cheap and plentiful and easy to work with, so why not. But you can use steel, aluminum, brass, whatever, so long as the ID and ODs are right for the damper rod.

If you cut 3" off the spring, and add a 3" spacer, you will have the same preload as stock and be 3" lower. If you cut 3" off the spring, and add a 4" spacer, you will be 4" lower, but have additional preload over stock, i.e. a stiffer front end, which depending on how you ride or what you weigh, might be needed when you lower the bike. If you add a 3" spacer and don't cut the spring, you will be 3" lower and have a super stiff front end, if you can even get it back together.

Same goes for cutting top tubes. Cut 3", but keep the same length spring, and you will have a pretty damn stiff front end. Even cutting a .5" off the spring might make it too stiff, but it's easier to cut more than to add it back, so....

I'm real happy with the way mine rides, and when I switch the lowers out and add spacers, I'm not really planning on adding much, if any, more preload than I have now. The preload I have now is enough to raise the front of the bike when I get off of it. Spacer will keep that from happening, but should ride the same.

[ironhed]

thanks this is a big help
cheers