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Hack in a barn
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4,409 Posts
Discussion Starter · #1 ·
Just finished this little project up this weekend. This is a mirror post from a sportster forum I'm on. Although these forks aren't going to be too popular around here I thought it could serve someone well with short inverted forks on their bike. I'll preface this post by saying these forks are perfect for this in that the ID on the outer fork tube is the same through out so bushings on the inner fork work no matter where they are just as long as the lower hole on the stantion tube is still above the seal and lower bushing in the outer fork tube there will be no fluid loss. I can't speak for all inverted forks, but in the case of these extending the forks like I did here can be done.


So back story, I have had buell 54mm WP forks on my 02 sporty for a while now. When I switched to the 17" buell wheels and under-slung shock the shorter inverted forks created a ground clearance problem. Shock has hit the ground a couple of times, once while going hard around a turn, which was unnerving to say the least.

It also dropped the front of the bike too low, which had negative effects on the handling. Now quicker turn in sounds all well and good, but it was at the extreme and really felt unstable at slower speeds. It would make the bike want to run wide on every turn. It also wanted to fight me and stand back up straight.

So a plan was hatched.

Here is a side by side of a finished fork (right) and a stock height (left).



To get there here is what I did.

disassemble your fork and drain the oil. It's ok to leave outer tube on if the seals and bushings are good. You will need to remove the damper rod though.



Here is the parts involved. 3/4"x1x2 spacer that goes under the damper rod. M8 stud that goes in the bottom of damper rod where the stock bolt goes. M8 bolt 60mm with about 10 threads cut off, to replace stock short bolt. M8 coupler and M8 hex nut.



Stud gets threaded into the bottom of the damper rod, then the hex nut goes on. I didn't get a pic of it but the coupler goes on after the hex nut. That will allow the bolt to go through the bottom of the fork and bolt down the damper rod.



End of the damper rod is ~0.947", that sits down on a ledge 1/4" high in the bottom of the fork.



So you have to get one end of the spacer down to ~0.947" to get it sitting right in the forks. If you have a lathe more power to you. If you don't and you are like me, :D, pop the spacer on 3/8" drive extension and go to your handy belt sander, letting it spin slowly on the extension as it sands.



Little hard to see but the taper on the right goes down to the proper size and is measured to be that diameter a hair past 1/4".



Again hard to make out but pop that bad boy taper side down into the bottom of the fork.



Go to the vise and bolt your now raised by 2" damper rod back in.



When putting the forks back together I raised the outer tube 2" from fully compressed to do the oil level. That was to compensate for the holes in the damper rod now being 2" higher in the fork. And to make sure the oil goes where it's supposed to go.

And back together, there is a magic marker ring around the right fork showing where the unweighted stock fork seal sat.



So, because I know someone will ask, the only thing that happens is the relation of the holes on the inner fork tube and the damper rod changes. The bottom hole on the inner fork is still well above the forks seal and bottom bushing so there is no fluid loss worries. Because the outer tube is the same ID though out there is now worries about bushing sizes not working in the new spot. Again all the holes are the same size just now the damper rods are higher so that's why I added the extra oil.

Here are a couple of before shots of the bike. Notice the nose down stance and how close the rear shock is to the ground.










Now here are the after 2" fork extension pics. :party-smiley:







Hope this helps someone out in the future. I can tell you honestly it feels way better now. The bike doesn't fight corners now. It feels like my stock suspension did in terms of turn in and stability.
 

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Hack in a barn
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4,409 Posts
Discussion Starter · #3 ·
Very nice. Between the forks and rear fender, looks like it's ready for some jumps.

Considered lower bars?
:) Not going to lie, first thing I thought when I saw the finished forks was wow those look like MX forks!

I have had dirt bars on the bike before and the big problem with them is the reach or "sweep". The "before" pics were with 1-3/8" Easton's woods bend and the 5mm offset risers to bring the bars back a little more. They offered the most reach I could get from mx bars.

Even those bars didn't have enough, it put pressure on my hips leaning forward like that, and mostly because I have arthritis pretty bad, it caused pain in that area. The "finished" pics have the stock bars on. They are pretty much the same bend as any flanders flat track bar and are the most comfortable for me...
 

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Hack in a barn
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4,409 Posts
Discussion Starter · #4 ·
PS-

Stock height, off the bike, top of cap to axle center line was 28-1/2".

Now at 30-1/2"

 
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