Installing Forks... Difficulty level?

corey · November 23, 2009, 05:17:05 AM

Okay guys... I'm eyeing up a pair of forks...
They are from a 2000 748. Fully adjustable Showas (the ones with the red fork caps)..

Can we discuss what I'm going to have to do to get these to fit?
There is the obvious, the triples will need bored up top and shimmed down below... I'm probably just going to get new triples though, it's a bling opportunity that I don't think I can pass up...

But what else is going to need to happen? I believe axle size is the same, at 25mm, and the caliper mount spacing is the same at 65mm... Is there anything else that should be of concern? Is there a difference axle "width" or anything that will affect my rotors matching up with the calipers mounted on these different forks?

Anything else anyone can think of?

Howie · November 23, 2009, 05:38:32 AM

You should consider proper springs and valving before installing them.

corey · November 23, 2009, 08:10:00 AM

Quote from: howie on November 23, 2009, 05:38:32 AM
You should consider proper springs and valving before installing them.

Thanks for touching on that howie, I'd been meaning to get into that as well.
Is there a source for what forks came with what springs stock? What would be "proper" springs and valving? Would the springs i would use for these 748 forks be different than the springs i would use for say, a Showa fork off a Monster? I'm about 195lbs when geared up.

cduarte · November 23, 2009, 10:10:52 AM

Quote from: corey on November 23, 2009, 08:10:00 AM
Thanks for touching on that howie, I'd been meaning to get into that as well.
Is there a source for what forks came with what springs stock? What would be "proper" springs and valving? Would the springs i would use for these 748 forks be different than the springs i would use for say, a Showa fork off a Monster? I'm about 195lbs when geared up.

there's a table on this link which has the stock spring rates for ducatis....

http://www.ducati-upnorth.com/tech/suspensionspring.php

corey · November 23, 2009, 10:47:53 AM

Interesting chart... But for these forks, would i follow the chart for Monster S2R? Or would i follow the chart for the bike that the forks came from (748)??

He Man · November 23, 2009, 11:01:18 AM

thats for the shock i think. not the front.

you would get the approriate rate for your weight that you would put on the s2r forks, but in the size for the SBK forks.

corey · November 23, 2009, 11:33:08 AM

Great. Thanks He Man.
So what I'm looking at is a fork with a stock spring rate of 1.02kg/mm...
I'm at about 205 when fully geared, sometimes a little more when packed for a weekend.
Racetech's calculator (as well as the calculator on Sonic Springs) are suggesting about a .90kg/mm spring rate.
Is the stock spring rate (at .12kg/mm higher) "dangerously" stiff? I feel like I would be really pissed off i went to a .90 from the 1.02 that is there, only to find the forks still too soft...

He Man · November 23, 2009, 05:52:48 PM

im no suspension expert, but it sounds like you should try to set up the forks with the stock springs.

im 150lbs (w/o gear) with .85kg/mm fork springs on S2R1k showas. They're awesome for both commuting and weekend riding, i just tweak my preload a bit to adjust it a bit and im set.

corey · November 24, 2009, 04:14:13 AM

That's what i was thinking too...
I mean, the worst that could happen is they prove too stiff and i need to remove them and have them resprung...
At that point, I should be good enough at removing forks that it's no big deal

Unless someone thinks it would be dangerous.... But what would be the difference in riding the monster with these heavier springs, vs. riding the SBK with these heavier springs?

He Man · November 24, 2009, 11:17:45 AM

Much more front weight due to geometry of hte bike + your body is more leaned into the front end + the idea that the bike is ment to be ridden hard, so the springs expect you to brake extremely heavy prior to turning in.

With a monster, there is much less weight on the front end, again due to geometry, your body weight on the front end + the fact that they dont expect you to go nuts on the brakes on the street.

if you look at taht spring chart (which is for shocks not forks) youll see the huge difference between an SBK rear spring and a monster rear spring. its much stiffer on the stock spring. They recommend for your weight , and 8 on an SBK, but a 10.5 for a monster.

so if you plan on swapping to an SBK shock as well, youll notice that the shock wont even be able to hold the bikes weight up without severely bottoming out ( and by severly i mean so bad that you might as well not have a shock).

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Installing Forks... Difficulty level?