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showa forks

Started by garryc, April 16, 2013, 08:40:39 AM

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garryc

April 16, 2013, 08:40:39 AM
I bought these new from ebay italy a while ago to replace my marzocs on my M600.
Can anyone tell me what model shocks they are are so I can find out if and how to adjust them when I get around to installing
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Cloner

#1
April 16, 2013, 02:15:37 PM
I can't tell by looking, but they're either 41mm or 43mm Showas.  Adjustments are the same, so what's the difference?  The large (22mm) nuts at the top adjust spring compression.  The small flat-bladed screw inside that nut adjusts rebound damping.  The small flat-bladed screw at the bottom (sticking straight down in your photo) adjusts compression damping. 

Measure the diameter of the chrome part to discover if they're 41mm or 43mm.  If you don't have a caliper, wrap a bit of string around one and then measure the length of string it takes to wrap it once.  41mm will take just under 129mm, 43mm will take just over 135mm....so they're far enough apart to do this with a simple tape measure.

You'll need to know that if you need fork seals or springs.
Never appeal to a man's "better nature."  He may not have one.  Invoking his self-interest gives you more leverage.  R.A. Heinlein

'64 Ducati Monza 250
'67 Aermacchi/HD Sprint SS (race bike)
'00 Aprilia RSV Mille
'03 Ducati 800 SS (race bike)
'04 KTM 450 EXC
'08 Kawasaki Ninja 250 (race bike)

garryc

#2
April 17, 2013, 03:29:19 AM
Thanks Cloner,
That is all the info I need.

brad black

#3
April 17, 2013, 06:23:51 AM
with 40mm caliper mounts they should be 41mm.  only fitted to 91 on 851, 888, 900ss and 900m special 98/99.  but they have a one piece outer.  the earlier ss, 851 and 888 had the seal holder section as a sleeve.  don't recall when they did away with that.

they'll need to be resprung and many people are fitting gsxr 750 (03 - 06 sort of era) catridges to them for a proper damping style internal.  as std they're fairly flawed.
Brad The Bike Boy

http://www.bikeboy.org

Cloner

#4
April 17, 2013, 08:54:37 AM
I know they have the separate seal collar through the mid 90s, as my 95 still has it.  It's a PITA to drive seals into sometimes.

Racetech make cartridge kits for 41mm Showa, as does Ohlins.  It's a 25mm cartridge.  There is a bit of drilling required to install them....and as Brad mentioned, no matter what forks they are correct springs are always a must.

Nice tip on the narrow caliper mounts, Brad!
Never appeal to a man's "better nature."  He may not have one.  Invoking his self-interest gives you more leverage.  R.A. Heinlein

'64 Ducati Monza 250
'67 Aermacchi/HD Sprint SS (race bike)
'00 Aprilia RSV Mille
'03 Ducati 800 SS (race bike)
'04 KTM 450 EXC
'08 Kawasaki Ninja 250 (race bike)

MonsterHPD

#5
April 17, 2013, 03:39:54 PM
Actually, these forks have 20 mm cartridges. I just did a set of these forks, the actual ones I did were from a 1998 Monster 900.
Internally, they look just like any other Monster 900/1000, ssie900, ST4 forks and need the same treatment to work properly (GSXR cartridges, or "Showa Blues" modification). According to some, it IS possible to get these forks to work with just a piston-and-shim kit, but I have not succeeded when attempted. GSXR cartridges or "Showa Blues" are sure to make the forks work properly. 
Monster 900-2002 (sold, alive and well in the UK), 749R / 1100 HYM combo for track days, wifes / my Monster Dark 800-2003 (not entirely "Dark" anymore and a personal favourite) , 50% of 900SSie -2000 track bike for rainy days-now with tuned ST2 motor and Microtec ECU. Also parked due to having been T-boned on track.

Cloner

#6
April 17, 2013, 05:43:17 PM
I did a set recently mounted on an 800SS (transplanted from a 1000SS) and they were a 25mm cartridge....but those were 43mm forks, weren't they?  Crap!  I'm feeling a bit moronic.  Too many forks on the bench, lately.

I have installed Racetech valve kits in 41mm forks before and they do work with the correct shim stacks.  The kit for the 43s I did recently was on Ohlins kit and the owner (who races the bike) reports it's working extremely well.....off topic, though, as I guess we're talking about 41s with a 20mm cartridge.

Glad Brad and HPD are around to keep us old folks straight.   :-[
Never appeal to a man's "better nature."  He may not have one.  Invoking his self-interest gives you more leverage.  R.A. Heinlein

'64 Ducati Monza 250
'67 Aermacchi/HD Sprint SS (race bike)
'00 Aprilia RSV Mille
'03 Ducati 800 SS (race bike)
'04 KTM 450 EXC
'08 Kawasaki Ninja 250 (race bike)

MonsterHPD

#7
April 18, 2013, 04:22:34 PM
Well, I suppose when it comes to Ducatis, no rules are 100%. Seems you've been working quite a bit on forks, so I won't dispute your experience, I can only vouch for my own. So far I've modified maybe 20 sets of these, lets say, slightly different Showa forks: 3 sets of the 41's off older Monsters, and the rest various 900SSie/)900 and 1000 Monsters, and one set 1000SS (actually, only one leg was 1000SS, the other was a 900SS). All of these had 20 mm cartridges. Did the 1000SS already have a cartridge kit installed?

Also, I've tried RaceTech and Öhlins piston/shim kits with various shimming, and have not been able to get it to work properly (no reaction to compression adjuster setting).  couple of weeks agi I was at Gareth Evans Reactive Suspension i York, GB, for  a suspension seminar. I learned a lot, among other things that he has modified some of these forks with just shim kits and have got them to work, but I have not had the opportunity to check one of those against one of "mine".   isimply don't know, I just know that as they come, they are crap, and with a Showa Blues mod they are as good as any other kitted forks.

I'd be very interested in knowing a bit more about how you did the racetech mods, and what the results were. Seems to be something to learn here  :)
Monster 900-2002 (sold, alive and well in the UK), 749R / 1100 HYM combo for track days, wifes / my Monster Dark 800-2003 (not entirely "Dark" anymore and a personal favourite) , 50% of 900SSie -2000 track bike for rainy days-now with tuned ST2 motor and Microtec ECU. Also parked due to having been T-boned on track.
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