Installing Forks... Difficulty level?

[corey]

Pretty straight forward here... how difficult is it to swap out forks? (ST3 onto an S2R800)...
What tools are needed? Etc. Etc.

Any info at all is appreciated.

[Slide Panda]

Only special item is a front stand with an under the triple attachment. Or some other way to suspend the bike from around the steering head area of the frame.

Beyond that, it's just your normal assortment of allens, sockets and torque wrench sort of tools. Some way to accurately measure the height of the forks in the triple is also something to have on hand. 

But basically, life the bike, off the wheel, loose the triple pinch bolts and slide out the forks.  Not hard at all

[ScottRNelson]

It's not hard to take forks off and put them back, but if you're changing them from one bike to another there are a lot of things that you need to check.

First, are the fork legs the same diameter?  Of so, then it's easy enough to slide them into the triple clamps.  If not, you'll need to replace the triple clamps too, and maybe deal with steering head bearings as well.

Second, is the front axle the same diameter?  I've owned Ducatis with three different front axle diameters, the 1993 888 is smallest, the 1997 Monster was in between, then the 1998 ST2 is largest.  If the axle diameter isn't the same, you'll need to put new bearings in the front wheel and possibly a new spacer in between them.  And on the older bikes with a speedometer drive used as a spacer on the left side, you'll have to get one that works.

Third, the brake calipers have had at least three different bolt spacings during the time that I've been interested in Ducatis.  You'll have to make sure that those match.


So if you don't run into any of those issues, you need a few appropriately sized allen wrenches and maybe one or two regular wrenches of the right size to make the swap.

[dlearl476]

Some way to accurately measure the height of the forks in the triple is also something to have on hand. 

This one caught me out before.  The measurement you want to duplicate is the distance from the axle to the bottom of the lower triple tree.  The measurement of the amount sticking out the top tree only works if your forks are exactly the same length.  If not, you're changing your steering head angle and rake as well.

[cduarte]

This one caught me out before.  The measurement you want to duplicate is the distance from the axle to the bottom of the lower triple tree.  The measurement of the amount sticking out the top tree only works if your forks are exactly the same length.  If not, you're changing your steering head angle and rake as well.

when I changed the forks on my monster, since I had forks that fit in the stock triple trees, I was able to  remove one leg, ensure that the axle holes lined up by inserting the axle, and then changed the other, again checking that the height was correct. I suspended the bike from the rafters of my garage with straps to remove the legs, it worked out well for me.

[ScottRNelson]

when I changed the forks on my monster, since I had forks that fit in the stock triple trees, I was able to  remove one leg, ensure that the axle holes lined up by inserting the axle, and then changed the other, again checking that the height was correct. I suspended the bike from the rafters of my garage with straps to remove the legs, it worked out well for me.

If you have both the old and the new fork leg out, why not just lay them side by side to see how they line up?  Wouldn't that be much easier?

[corey]

Thanks for all of the input guys, it is much appreciated.
I am aware of all the small issues. The forks I am looking at are indeed correct when it comes to triple measurements, axle diameter, and caliper bolt spacing. sounds like a pretty straight forward job.
I also do have an under-the-triple type front stand, so should be fine in that regard.

when it comes to torqueing in the new forks, is there anything i need to be careful of?

[cduarte]

If you have both the old and the new fork leg out, why not just lay them side by side to see how they line up?  Wouldn't that be much easier?

not really, the way I did it ensures that the new forks are installed to exactly the same position as the old ones. It didn't take very long either.

[Spidey]

It's pretty easy.

when it comes to torqueing in the new forks, is there anything i need to be careful of?

When you slide the new forks in (or the old forks out), stick something in the triple clamp to wedge it open .  Otherwise, it's easy to scratch the forks.  Try not to use a screwdriver as it'll gouge your triple.  If you have something plastic as a wedge, that works best.  

Don't put one fork in and then tighten, and then install the other fork.  They can be cock-eyed.  Instead, install both forks (you can tighten either the upper or lower just enough to stop them from sliding out), twist them a bit in the triples to make sure they're seated straight and then tighten 'em up.

[BK_856er]

when it comes to torqueing in the new forks, is there anything i need to be careful of?

In addition to the good input already provided, be sure to obey the torque specs, thread treatment and 1-2-1 etc. gradual tightening.  Do a couple of reality check measurements on the fork heights and also be sure the axle also slides in easily.  My forks like to oval the axle if I tighten the axle pinch bolts to spec, so I use the low end of spec range and all is good.

BK

[IdZer0]

In addition to the good input already provided, be sure to obey the torque specs, thread treatment and 1-2-1 etc. gradual tightening. 

Can someone explain what this 1-2-1 is for ? Why go back to the first bolt when it's already torqued to spec? Or am I missing something?

[Ddan]

If there are two bolts on a clamp tightening the second is going to take load off the first, so it needs to be re-torqued.

[2001cromo]

Also , tighten the bottom axle clamps last (after both triples are tight and you've bounced the forks up and down a few times.

Then tighten the axle clamps.

[ScottRNelson]

Also , tighten the bottom axle clamps last (after both triples are tight and you've bounced the forks up and down a few times.

Then tighten the axle clamps.

I don't trust bouncing the bike up and down to properly align the forks.  The best way, as explained by Phil Douglas of Aftershocks Suspension and which I haven't done myself, is to pop the fork caps off so the springs aren't helping, then compress the forks all the way and use that position.

What I do instead is leave the left side loose and see how far in and out I can move the fork leg.  On my ST2 I can move it about 2 mm.  I then center it about that range and I get smooth fork operation.

If you don't get the leg centered on the axle the forks will bind a bit and you won't get smooth operation.  I've experienced that, so I pay special attention to alignment whenever I have a reason to loosen things up in that area.

[scott_araujo]

Can someone explain what this 1-2-1 is for ? Why go back to the first bolt when it's already torqued to spec? Or am I missing something?

On the lower triple there are two bolts right next to each other for the fork leg.  Now there's an air gap in that little slit, this isn't metal to metal.  When you torque the second bolt everything compresses a bit more, kinda like getting your kid to sit on an overstuffed suitcase when you're already pressing down.  That can make the first bolt a little loose so you need to recheck it.  I just go back and forth between them until they're both tight.

Scott