MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECH

As of  late, I have been trying to gather pics and information to start some low buck garage tech tips. One of the easiest and cheapest mods to do, would have to be lowering the front forks. When lowering my forks a few months ago, I attempted to take a couple pics of the whole process. As I sat down to write this very article, I realized that I do not have what it takes to make a full article from beginning to end. In usual form, I failed miserably at taking the time to stop and snap pics of each step.  With my camera in hand, I start to step into the garage to snap some photos of the whole process (again). Right before – I get past the threshold, I recall a full write-up archived at one of the forums I frequent. The Chopper Underground. In order to make sure credit is given where it is due, I would like to personally thank Justin for his willingness to put together such a well written/pain free step by step. He was gracious enough to allow it to be placed here at XS650chopper.com for all of you chopperfiends to see and learn from.

Send in a How To article. Use the submission form here.

What year is your bike? – See the xs650 Model Year Identification Chart.

THE PROPER WAY TO LOWER YOUR XS650 FORKS

AND SO THE JOURNEY BEGINS…..

To disassemble the tubes from the slider, you will need an 8mm allen wrench for the bottom of the slider and a 17mm allen to hold the damper rod in place. I did not have the 17mm allen, but I did have an extra fender bolt that fit the bill perfectly.
MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECH17MM2

I used red lock-tite (permanent) to secure the acorn nut to the bolt, which ensures the two will not separate before the damper rod does. I then used a 17mm socket attached to a series of extensions to place the acorn into the damper rod.

Now that you have fashioned a suitable tool for the damper rod, we proceed to dissasembly. The first step, is to take all the preload out of the fork tube cap. This will lessen the chance of your cap shooting across the room and putting out an eye. This is done with a large regular screwdriver. You will need to push down hard while turning, until it comes to 1/4” below the surface of the cap.

 

MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECHforkparts5
MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECHforkparts6

You will now need to lift bike so the front wheel is off the ground. Now you can remove caps. It will pop up a little bit when it unthreads fully. Do not lose the solid washer underneath the cap. Do this with one or both trees still fastened so the tubes do not rotate. Pull out the fork springs and set aside. Loosen the pinch bolts on trees, and remove forks/sliders. Drain oil from tubes.

Now place slider in a vice. I used the mounts for the caliper and some blocks of wood as to not scar the aluminium.
MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECHforkparts1

Place socket and 17mm allen tool into fork tube and the 8mm allen wrench in bottom of slider. Mine worked out to the socket wrench hit the bench, so I didnt even have to hold it in place. I also used a small cheater bar (3/8” socket extension) on the 8mm allen wrench.
This bolt is locktited from the factory, and will give resistance all the way out. I would advise using blue loctite during reassembly. Once the 8mm bolt is removed, you can slide the fork tube out of slider.

The damper will slide out of the top of the tube, and the small damper spacer will come out of the bottom of the tube. Clean all of the internal parts as you disassemble, to rid them of sludge from ancient oil.
MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECHforkparts4

MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECHforkparts2

By now you should have your forks dissasembled and ready to make your desired lowering spacer. I used a tube from an old dumb bell, that is 1” o.d. and 20mm i.d. (never throw metal away). Here is lowering spacer installed on damper rod below the small spring.
MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECHshockguts

A comparison to the stock fork assembly.

MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECHshockguts1

Here is what needs to be cut off the large spring. The springs in these are progressive. Which means it has a tighter coil pattern at the top, compared to the bottom. I will be cutting the spring from the botom, so I can keep the progressive action of the spring.
MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECHshockguts2

By now, you should have your spacer made to desired length, and be ready to cut your larger spring. I chose 1/4” shorter than than the length of lowering spacer, which equals 2”. Just to clarify my spacer was 2 1/4” making 1/4” of extra preload on the springs. I bought a 10” metal cut off blade for my chopsaw.

It was $5 at Lowe’s.

A small price to pay for an accurate cut on a spring. I set up a stop block on my saw to 2”, including the width of the blade.
MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECHchoppingsprings1

now my springs fit 3/4” lower than the tube, which is 1/4” higher than stock.
MULLIGAN MACHINE: LOWER YOUR XS650 FORKS; LOW BUCK GARAGE TECHchoppingsprings2

 

Now is a good time to shave your sliders of any unused tabs before your final reassembly. Do not forget to add blue loc-tite to the 8mm allen bolt during final reassembly. It may seem that the bolt cannot come out due to the axle placement, but the damper rod may unscrew from the inside resulting in a tragic wheelie.

This concludes your XS650 front end lowering class.

For more articles check out the XS650 Chopper Do It Yourself Library

Justin

If you have any extra tips or possible slight differences you have seen between different year forks, feel free to comment below and let it be heard. Once again Justin, I appreciate your effort and time as well as many others.

Thanks

 Leave a comment below!

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Comments

  1. Tech articles are AWESOME!!!!!! Without these, I would have no Idea on how to do anything to my bike. I definitely support a tech library section. As I build my bike more and more, I turn to places like this for help if I don’t know how to do something. I got an ’83 xs, and will be performing the front fork lowering, and eventually the charging system re-wiring.

  2. Ted says:

    Cool martin.

    I was thinking of doing a whole tech library focused specifically on common things that guys do when Chopping a xs from start to finish however, there is no way in hell I can do it myself. It is awesome to have guys like Justin, CAPTAIN AWESOME, Brian Durk and other guys down to contribute.

  3. Larry says:

    Yes, tech articles are GREAT!

  4. dave says:

    MOAR!!! I live for tech articles

  5. HenkelMike says:

    Definately more tech articles, they are very useful.

  6. dave says:

    Tech articles are gold for motorcycle and mechanic newbs like me!

  7. andy carter says:

    i would be down to write some if you want. lord knows i have enough pics. let me know ted and i will write some up or you could just direct people to my blog if you wanted? either way works.

    -andy carter

  8. metalho says:

    Cool justin lower case, LOL………….. Glad to see this tech article posted, you did a great job on it. Thanks man! You be bro status. Did you get a pic of your scoot posted, its worth lookin at!

  9. bob parsley says:

    awesome. more more more…

  10. i vote YES for more tech!

  11. Phrog says:

    I’ve just started my chopper / bobber project and tech articles like this one will be indispensable! More tech articles for us aspiring builders would be more than welcome!

  12. justin says:

    wow, im glad you like, ive tried to post a pick but…

  13. frank GRC says:

    awesome!!! thanks alot for the time and effort it took to do this, just goes to show how much you love the bikes and the people who ride them. love to see more tech tips

  14. Blacksmithbilly says:

    good tech articles = less wasted time & money

  15. Keith Allibone says:

    Listen, I just finished my bike a few weeks ago and I just found this site a few days ago. I’m now on here everyday. I would have killed for a site like this with some decent tech articles. I know there are some good ones out there but I favor this site cause mostly all the bike on here are kick ass and its just set up well. This site has inspired me to do another build and make some changes to my current ride. I’m down for the tech articles, bring em…..

  16. Ted says:

    @ Keith
    cool man.. Glad that you found the site.

    Looks like we are going to have to start a xs650 chopper tech library.

  17. Rusty Nutz says:

    Yeah more articles.

    I’d like to see more closeup details like how to mount a rear fender on rubber mounts in excruciating detail. Also how to add a disc brake to a springer. How to mount the rear disc cylinder to a hardtail. How to mount fake oil tank on rubber mounts.

    Good detail on this article btw. thnaks for saying where to get cutoff blade.

  18. Angry John says:

    More tech!

  19. Ted says:

    This post came in very helpful this afternoon. I shaved the tabs off the lower Fork tubes today and installed the lowering spacers..

    @Angry John
    We will have some more tech articles soon man.

  20. J-Bagz says:

    do you know of anyone that offers a service of shaving the lower legs free of the fender tabs/brake tabs

  21. reynoldburton says:

    Big thanks for sharing “fork lowering knowledge” to us! I did it today, and it looks really great. It´s such a difference for that low (or no) bucks – more tech please!

  22. locO leoN says:

    hey what a great thread!!..
    I have a gorgeous set of Girder forks that was modified with an XS650 neck for sale if anyone is interested:

    http://dotheton.com/index.php?topic=11459.0

    It would be a straight bolt on to any xs650 frame!!..

    Its located in Toronto Canada…

  23. bird says:

    awesome. i have a basket case ’74 xs in my basement. the more bikes i see, the more inspired i become. and, consequently, the more bikes i see with custom stuff i want, i don’t know where to begin. this article is fantastic. thanks for posting it. i have been looking for some step x step instructions (with pics no less!) for lowering the forks. keep ‘em coming please!

  24. jimster says:

    great article!
    How low can xs forks be lowered? Is 3 inches too much?

  25. justin says:

    jimster,
    i lowered mine 2 1/4” and drew a line on the fork tubes with a marker. after going for a ride it was 1” away from bottoming out. so id say that 3” of lowering would leave you with 1/4” of play left. i fill my tubes to 6” from the top,springs out, forks compressed. you could fill it a bit higher or use a different weight of oil to stiffen it up some. i think i used straight 10w..
    justin

  26. Bow says:

    Love to read all the good tips over the technical stuff,you never to old to learn

  27. Skylar says:

    So, if my forks are stock- but I want a stiff ride w/a small amount of rebound, I’d go with 10W ATF, in what amount? Can’t seem to get a good answer on this.

  28. Tomcat says:

    Did this mod today. Nice write up. Thanks. I’ll be using a mid weight motor oil like 20w to fill to stock level.

  29. Mike Root says:

    I have a question to those who have done this: On the dampner rod there is a hole where the spacer should go that will be covered by the spacer. How will this effect dampening? That hole should be able to have flow should it not?

    Root

  30. Ted says:

    @ Mike Root- There were multiple holes on the ones I lowered. Also, the spaces I used were not completely tight around the lower connecting rod (oil could still make it to the hole). This mod has been done by hundreds of people. It works.

  31. Bryan says:

    I’m trying to lower my forks on my 75′ and my inner parts are different. I don’t have that little spring. Instead I have a metal tube spacer that is approx. 3-3.5″ long. I’m assuming after I cut my springs 2″ shorter, I make a new tube spacer that is 2″ longer than the stock one? Does that sound right? I’m really trying to get my forks back on soon. Thanks

  32. chris says:

    is there a place where i can purchase these spacers? pls email me at socerlife3@aol.com if you know… thanks!!!

  33. Ted says:

    You could probably find some spacers at a hardware store. However, if you have a old set of handlebars lay around you could just cut the end off and use that as a spacer.

  34. Mister says:

    I just completed this project, used old handlebars for the spacers. I just need to stiffen up the suspension a little bit. And don’t try this without a vice, I did and was unsuccessful to get to torquing right, so will have to re-do it once I get a vice, looks good lowered! Don’t worry I wont be riding it anytime soon.

  35. Joey says:

    I’d like a littel more detail about taking the preload out of the cap. All it says is “take all the preload out of the fork tube cap…This is done with a large regular screwdriver. You will need to push down hard while turning, until it comes to 1/4” below the surface of the cap.”

    Push down on what?
    Until WHAT comes to 1/4″ below the surface of the cap?

  36. REEB! says:

    So if I need to take 2 7/8 out to level out my frame do I cut 2 7/8 out minus a 1/4? And what determines the length of the spacer?

  37. REEB! says:

    Joey….push down hard on the screwdriver to back out the bolt That is at the top of you forks. This takes the tension off. And it would be the sane bolt that cones to a 1/4 below the cap

  38. This is REALLY GREAT…- An invaluable Resource…- Really Appreciate the guys who dont mind sharing what they know….

  39. REEB! says:

    To correct my last comment you push down on the preload adjuster to take the tension off the spring. Inside the tube is a three step pattern pushing down and turning to the right is more tension on the spring. You will be pushing the screw down just over an inch. But to remove the caps u need to push down and to the left. The screw will not come out. It stays in the top cap. Put a 22 socket on the top and spin it off. Then spring will be exposed.

  40. Eric Plough says:

    Tech is always good, MORE, MORE, MORE…………..

  41. pastorchris says:

    I have a 1974 650, my downtubes have an air valve at the top of each tube? Is the preload below this? This may be dumb but i am new at this. Thanks

  42. pastorchris says:

    My tubes have air valves at the top. I got the tubes out of the sliders but how do I get the springs out? Their is a sanp ring at the end that went in the slider. Why are my tubes so different? My bike is a 1974 650.

  43. Steven says:

    YES YES YES

  44. ray brown says:

    I’m curious as to wheather or not this process will work on a set of yamaha dirt bike forks. If so,how could I download and or print this info and pix. I’m not doing an XS,unfortunatly, but it is gonna be yammie based if I can make it run. Any info would be a big help. Keep choppin an makin sparks,ya’ll!!!

  45. Matt says:

    Tech write ups are the shit. I feel very strongly about that and could talk about it for a long time. I’ll keep it short. Keep writing tech articals and write as many as you can. The type of people that you are aplealing to are thristing for more knowledge. The action taking to do this will only have positive results. The knowledge shared could have been lost and forgotten. How much of our wisdom on building choppers, the way they used to do is already becoming a lost art. That kind of knowledge deserves to live forever, for all that have the calling to build a freedom machine with there own two hands.

  46. Piute says:

    Amen ,Matt.I come back to this sight and others just for tech , and see what has risen from the dead

  47. Strafemall says:

    Tech tips are awesome ! Thanks ! :)

  48. Alex says:

    So true!!
    Lost my Dad this year and a ton of fantastic information like this is gone forever,
    Keep it coming!

  49. Drew says:

    Thanks for the guide, Justin. I just completed this process on my 1980 Honda CB400t; the forks are almost exactly the same as the XS650. The only difference is I used 1/2 inch 600psi PVC for the spacer (super cheap and progressive includes PVC in their spring kits for spacers). The more aggressive stance really improves the profile of the bike. I haven’t had a chance to test ride yet though. I will try to update afterwards. Cheers!

  50. Iñaki says:

    Ey! Thanks for the Tech tip. I’m from Spain, I want to lower my Honda CB750 and this help me very much ;)

  51. $hawn says:

    What about holes in the spacer to allow fork oil into valving ports in dampner rod?