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Discussion Starter · #1 ·
For those in the know...

Are the forks on the Superbikes all created equal? Any models/years more desireable than others in terms of a monster fork conversion?
 

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To save money, you might want to look for a set that has the same caliper bolt spacing as your current forks which should be 65mm. (pre-`00 40mm vs. `00+ 65mm)

They all have 25mm axles, so you should be good there.

I'm not sure if there was much in the way of internal changes over the years, but since you'll probably looking at later models, you should be getting close to the latest/greatest.

BTW, I just bought a set of `02 748 forks in nearly perfect condition (to use on my SS) for $220, so now is a good time to be in the market.

--Fillmore
 

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How hard would it be to fit forks from a '98 748 on my '01 monster 750 dark? Is there a conversion kit for the calipers? I can get a set in awesome condition for 250, should I hold off for newer or jump on these and somehow retrofit them?
 
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i believe the 98 forks were the last year for the 40mm caliper mounting brackets on the 25mm axle forks... not sure what your brackets would be on the 01 monster but i'm guessing it's 65mm. if it's not 40mm then it'll be 65mm. i know ducati kaemna sells adapters for the calipers if you have 65mm brakes and 40mm fork mounts... you may need longer brake lines though. motowheels may be able to hook you up. imo it's easier and more cost effective to get forks that bolt up to your caliper spacing than spending the extra dough on brackets and brake lines.
 
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I was told by BCM although I haven't confirmed, that there is a difference in valves between the 748 and the 9** type showa sbk forks? The drift was that the 748 ones were not as good....I do not know if that is true.
....I've heard some say the sbk's are on the soft side and others say not......mine for example will need new valves as the comp damping is still too much all the way out and maybe different springs as the pre-load is all the way out also....I can dial in the rebound but these guys are the stiffest forks I have been on and I am 220 at least.....so it may matter indeed what bike they are off of.....? Perhaps the R versions are heftier for example.....?
 

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Retro,

Just curious about your fork symptoms, as my S4 forks seem to be acting similar...Even with the compression adjuster all the way out (soft), on cracked/slightly irregular pavement or on the SoCal freeway washboard at 50 mph and above, the fork feels like it doesn't move, then in moderate or bigger normal single bumps or dips it's sloppy soft?
Is that what you've got?

Anybody know if the S4 forks are the same as SBK forks?

I've talked with Dan Kyle about his fork mods, I'll most likely be sending mine off to him. RaceTech's right around the corner, but I've talked to them on the phone several times and have yet to find someone there that knows their @$$ from a hot rock.

Moto, where_do_you get those url's? ;)
 
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RE thoughts:
Hey Nick.....no I don't have what you describe. No sloppy soft.
I just have too much comp damping....and prolly too stiff a spring,
not enough travel is being used, and who knows until I change the oil, what is in there.
I believe there are differences in the S4 and SBK's and even between SBK's. But then again what do I know? :)
The most I can tell at the moment is that there are at least minor internal component difference's in the parts catalogs. You will notice a flexible collar around the damper tube on SBK forks and not on the S4's for example.
I am interested to see what comes up when the R version parts will be available. But where are the real Showa parts lists hiding?
And who has them?
My limited experience says it sounds like you have too much FAST comp damping and too little SLOW comp damping.
Some valving and shim stack work and possibly a different spring should get you sorted I am guessing.
Let us know what you find out please and what Kyle's approach would be, I don't believe he is a
 

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Phill_B,

Did you go softer springs because you are lighter than the so-called 170lb average that stock set ups are intended for? Or was it just that your bike suffered from the harshness you described?

That ought to be some great trip to Philip Island!
 
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....I've heard some say the sbk's are on the soft side and others say not..
i think it's dependent on the bike the forks are on and the weight of the rider... to my knowledge the sbk forks come with a .95 spring because of the heavier bike weight and forward weight bias. when i say heavier, it's in reference to a monster or supersport. the monster and supersport spring rate is .9 and is a bit anemic for larger riders. i've found that the sbk forks grafted on to my 900ss are more than adequate for my 225lb lard ass. whereas they are sorta soft on a friends 996.

the conversion was a night and day difference from the nonadjustable 41mm marzocchi's to the fully adjustable 43mm showa's on the 900ss. i'm actually fairly pleased with the monster s4's front suspenders off the showroom... the only wierdness i experienced was after the one fork was reassembled incorrectly... when that was properly fixed all has been fine suspension wise since. i'd like a bit stiffer spring on the rear shock though.

not sure why the 9xx forks would be any different than 748 forks... bike weights are similar... seems like an uneccessary cost to have different valving for the two. usually they'll just put nitride coatings on the bigger displacement bikes but i've seen wierder stuff happen too.
 

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Retro,

Well, "sloppy soft" may have been overstating it a bit...

But yes, I agree with your assessment, too much fast comp damping, too little slow comp damping. The damping adjustment screws seem to effect the slow speed damping much more than the high speed. I can tighten the adjusters back up, and get the slow speed damping better, but the high speed goes from bad to worse.

I think I'll try an oil change first, before I send the forks (and a coupla franklins) off to Kyle.

My main problem in figuring out what's going on is I haven't had a set of cartridge forks apart, so I'm not aware of all the parts..........
 
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I hear ya!

oh I forgot I have a couple of fork vides if you want to look at them I could send them to you....the Racetech one is pretty good and goes through the whole internals and taking everything apart..
let me know......you can send them to Malibu when you're done.. 8)
 

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Phill B,

You weigh 190 and went with softer springs ? ? ? ?
---------------------------------------------------
That may explain why the fork feels harsh to me.....
I'm probably 160 fully geared up. I reduced the preload about 1/4" from the stock position to get the static sag right.

I'm using all but maybe the last 1/2" of travel, on some pretty hard hits. I'm assuming that the forks have a hydraulic bottoming cushion, like the top hat & damping rod setup on conventional forks ("right side up") from back in the day.
 

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Slightly drifting off topic, but this is some interesting stuff in this thread. I've been pondering getting some Race Tech .90 springs for my non-adjustable Showas based on their spring rate calculator and some dialogue with Chris.

But, I did a thorough test and measurement session a few days ago and found that I'm using 93mm of travel from total extension. That leaves 31 mm of slider unused below the zip tie on the roughest roads and some good hard braking.
Sag with me on the bike is a whopping 49 mm. Most sources state that the sag should be around 30-35 mm for street. Ducati says 45-50 mm! While I was at it I measured friction effect/"stiction" by Race Tech's method and fell in the good range of less than 15mm.

Even with that amount of sag, I've never bottomed out the front. It always behaves well, too.

I've gotten into such a dilemma as to what do about spring rates; having to mess with the valving; oil choices; etc., to get them dialed in again if I upset their balance by changing one of the parameters (not a cheerful prospect on non-adjustables). So I went off on a tangent and picked up some SS type adjustable Showas. At least with them, if I diddle with spring rates, I can also play with damping to get them set up properly.
 

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I'm at about 40mm of sag, I like the more "off-road" sag percentage.

I checked, and I'm using 101mm of the 120mm of travel.

What fork oil are you folks using?

My service manual says Showa SS8 or ATF. Haven't checked, but I don't think Showa SS8 is going to be on a shelf at the local MC shop. Not about to use ATF, who knows what weight it is, so there's no way to make a rational choice.
 

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I don't know what kind of oil or maybe sludge is in there now. I'm changing the fork oil along with the 15,000 mile stuff I'm starting on now. I think Ducati specifies 7.5, but I'm not sure. I'm going to try some Belray 10 wt in them before I swap out the forks. That will give me a chance to eyeball the springs in there and check free length plus ride them with clean oil and see how they feel.

Before I put the adjustables on, I'm going to check their springs and put in fresh oil as well.

It's not like routine maintenance is enough to keep me busy - I have to invent things to work on ;D
 
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What fork oil are you folks using?
Re: oil After doing a little research on fork oils I am going to go the expensive route with the Ohlins oil...the bits of info I have gleaned which of course could be marketing bull....is that the benefits of the more expensive oils are prolly worth it....
My understanding on weight is also that the SBK forks are normally 7.5.
I will be trying to band aid my comp damping with 5 wt. though this time around, until I get the forks into a shop to look at the internals.
I also thought that heavier wts. were for non cartridge forks....?
 
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