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A guide to SV650 forks

249K views 437 replies 96 participants last post by  51n 
#1 · (Edited by Moderator)
UPDATED 10/5/04

it seems as though a lot of us SV'ers are not satisfied with the stock suspension. we are always tweaking this, adding that, or replacing everything!

so I thought it was high time someone wrote a little guide for those who are planning to upgrade their forks or just want more information on what their options are. I am not an EXPERT or a PROFESSIONAL, but the suspension is something that really interests me so I read books, watch DVDs, and discuss it on these boards whenever I get a chance.

DISCLAIMER: anything you do with these instructions and advice is purely your choice and I claim no responsibility:lol: I will correct any erroneous info I post, just let me know.
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STOCK FORKS:
the stock forks are something that was stuck onto the SV to meet its price point. they had to cut corners somewhere, and the forks (and rear shock) helped them do that. they are basically a very low-tech damping mechanism. they are what are called damper rod forks.

damper rod forks are named after the damper rod (duh), which is a tube inside the forks at the bottom end of them. they have 4 holes drilled into them that oil flows in and out of (5 countings the small top hole). as you apply the brake or let off the gas abruptly, the oil in the forks is pressed through the damper rod holes. the faster you brake, the faster the oil gets pressed through the holes. the damping effect comes into play when only so much oil can get through the holes at one time and its creates the effect of slowing the dive. has to do something with hydraulics, but I'm not gonna get too technical here.

the rate at the oil gets pushed through is determined by a few things:
#1: the weight of the fork oil (the heavier the oil, the more damping)
#2: the stiffness of the springs (the stiffer the springs, the less likely they are to compress)
#3: the size of the actual damper rod holes
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STOCK FORK PROBLEMS AND SOLUTIONS
the stock forks come sprung really soft from the factory, and it's very hard to get correct sag numbers from them for a rider of more than 150lbs. they also suffer from watery fork oil. I believe it's 5wt from the factory, but I know for a fact that it's not more than 10wt. these two things when performing in concert, add up to a severely divey front end. if you've ever had to stop suddenly, you will definitely notice the huge dive from stock SV forks, maybe they even bottom out. and forks SHOULD actually dive, but not as much and as uncontrolled as the SVs do.

there are several routes you can take to fix these problems.

#1: stiffer springs. these help by giving the forks more dive resistance.
the most popular fork spring maker for the SV would be racetech ( www.racetech.com, they also offer svrider.com members a 20% discount on parts purchased through them when you mention that you're a member and give them your member name). you can answer a few questions on their website and they give you the proper spring rate for your weight.

#2: thicker fork oil. thicker oil will basically give you more damping because less of it can flow through the damping holes at any given time.
fork oil comes in many brands, I use bel-ray 20wt. I would suggest 20wt or heavier oil, though you will probably wanna play around till you find out what combination you like best.

#3: the race tech gold valve emulator. the race tech emulator is a device that attempts to partially turn your forks into a more modern cartridge-style fork by giving you compression adjustability. basically, you drill out the holes in the damper rod until they are useless as a tool for damping. this turns over control to the emulator, which sits atop your damper rod. when combined with a stiffer spring and thicker oil, it is a very effective tool in combating severe nose dives.

the combination of all three is a great setup for everything from commuting to canyon carving to even racing! some people even say that the gold valve emulator is not really needed, even for racetrack use.

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FORK SWAPS
the problem with the above setup is not really its LACK of adjustability, but its EASE of adjustability. controlling compression (assuming you have the emulator) requires you to put your bike up on a triple tree stand or hang it so the wheel is suspended, take the fork caps off, and use some sort of magnetic device to get the emulator out of the fork, adjust it, put it back in, and seal everything up. to adjust the rebound, you have to REPLACE the fork oil, which requires either a vacuum of sorts or the removal of the forks and dumping the oil out. THEN you have to factor in what your different oil did to your compression settings on your gold valve. this would start to be a pain in the ass, especially if you are at the track and you need to adjust your stuff on-the-fly. which leads me to what a lot of SV'er are turning to fork swaps.

people turn to fork swaps because of the ease of adjustability. need to adjust rebound damping a little? turn that little knob with a flathead screwdriver. The same goes for compression, turn a little knob with a flathead and find a nice spot you like. what you get as an added bonus (in a swap from more modern bikes at least) is better brakes, and sometimes inverted forks, which have their own bonus list. there is also another route to go, which I haven't done too much research on, which is swapping the internals and lowers of the stock SV forks, for honda f3 internals, which is cartridge style. I won't go too much into this because I don't know much about it yet.

Theoretically, you can put damn near any fork you want onto the SV. zx6rr's, gsxr's, r1's, etc, etc...almost all will require the entire front end; forks, triples, wheels, rotors, brakes, clipons, fender...

the most common would be the GSX-R forks. out of the GSX-R forks, the two most commonly used for swaps are 96-99 SRAD 750 forks and the 00-03 750 forks. they are both USD (upside down) forks made by showa. the 00-03 forks are known to be some of the best stock forks ever put on a bike (besides European Ohlins bikes). they are cartridge-style forks, basically having two different valves that control compression and rebound.

speaking only for the 00-03 gsxr 750/1000 fork swap, the 99-02 will need some modification (read below), the 03, and I'm pretty sure the 04 as well, I can't get ahold of the fiche files to confirm this, need no modification whatsoever, they will bolt right up to it.

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ISSUES WITH SWAPS
there are a few issues you will be dealing with if you decide to go the swap route:
#1. the 99-02 SV needs either a special steering head bearing for the gsxr swap, or you can braze material onto the existing bearing. TWF (look his name up in the member directory) sells the bearing you will need. this will be the case for a lot of fork swaps.
#2. you will lose your front drive speed. recently someone figured out how to refit the speedo drive onto the rear wheel. here's the link:
http://www.socalsvriders.org/forums/showthread.php?s=&threadid=10167
the exception would be the R1 front end, it retains speedo use.
#3. if you have a naked, you will need a place to remount your speedo and headlight. if you work well with metal, this should be a breeze, if not, you probably want to contact a fabricator shop to have them bust you out some bracketry.
#4. most of the swap forks are shorter than the stock forks. for this reason, the bike will tip in faster than before. the trail is not an issue though, because the sv has tons to spare.
#5. some people will say that you have to revolve the swapped forks for them to actually work a lot better than the stock forks. this is not true, BUT, there is always room for improvement.
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COST
stock fork stuff_______________________
fork oil: 4-5 bucks, depending on the brand.
racetech springs: 100 bucks (~90 shipped with the strider discount)
racetech goldvalve emulators: 130ish, you can find used ones sometimes.
pre-drilled and brazed damper rod from Traxion dynamics: 100 bucks.
the whole package from Traxion (springs, oil, Traxion damper rod, emulators, labor) is 450 bucks plus shipping. basically, you send them your forks and they upgrade them for you.

swap fork costs________________________
forks: 175-600
wheel and rotors: 170-300
brake calipers and controls: 50-100
triples: 40-70
fender: 50-80
axle: 20?
steering head bearing: 55?
special GSX-R wheel tool: 10-24 (depends on your make and model of front end, you can either get a huge alan key [19-27mm] or a GSX-R wheel tool off eBay, look for a seller named komodo dragging)
entire front end (recommended): 600-900

eBay is your friend for parts. so are boards like this and racing boards, racers love getting new stuff and parting out old bikes, and you can reap the benefits of this if you just troll around race message boards.

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SWAP COMPATIBILITY LIST:
wheels:
00-03 GSXR750 wheel will fit in:
--00-03 GSXR600 forks
--00-03 GSXR750 forks
--01-03 GSXR1000 forks

triples:
96-04 GSXR750 triples can hold:
--basically, any forks that have 50mm tops with 54mm main tubes
(to be continued)
have fun.
 
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#428 ·
A couple more questions. I have the comlete 04 GSXR 600 Forks, an 02 wheel, 04 600 Rotors, TWFs bearing. I'm lurking ebay for a fender.


I think i need the following, but don't know where exactly to track this stuff down.

1. A dust seal for the top bearing. Anyone have a part # for this?

2. A speedometer solution. I've searched and searched but can't find a contact for JimSVs solution. I'd prefer not to buy it from SVRaceshop.

3. A special tool to remove the security bits on my ignition. (Auto parts store?)

4. A special tool to tighten the castle nuts on the new front end.

5. What else am I missing?

Any advice on where to locate this stuff would be great.

Thanks!

aaron
 
#429 ·
Is there any functional or mounting difference between the 04-05 GSXR Gold 750 calipers and the black 600 calipers. I've been looking at the pictures on EBay and they both look like radial mount 4 piston units but I'm not sure about the rotor size.

Do I need to everything from a 04-05 GSXR 750 or can I mix it with items from a 600 like rotors, triples, fenders, axle and front wheel.

Also, does anyone know if there is any difference between the 05 and 06 600 front end. I'm see a few 06 forks starting to show up on EBay and I kinda like the black forks. Thanks for the info
 
#436 · (Edited)
Hello everyone-- I need some quick assistance.

If I were to win the following auction:

http://cgi.ebay.com/ebaymotors/fron...003QQitemZ130211889852QQrdZ1QQsspagenameZWDVW

What else would I need to make this work for my 01 SV650S race bike?

Yes, I have read through the "guide to SV650 forks" thread, but there are so many posts it left me confused! So I don't know what works with what anymore!

I presume I would need the KWF bearing, right? Would the ignition keyhole match up correctly?

Also, would I need new internals or valving?

Thanks in advance!
--Justin
 
#437 ·
A few things you'll need.

1) Top bearing (I'd get this from Zoran) and make sure you notch the frame where the bearing goes in so you can take it back out in the future.

2) Top triple would have the ignition in the center for the steering lock to possibly line up (but you're using on a race bike so this should not be an issue)

3) Steering stops (you'll need to make your own) as they're different and without them, the forks hit things...

4) Steering damper (if you're using the stock GSXR in that ebay sale you'll need to cut away the original steering top on the front of the headtube and make a bracket that will mount the damper in front of the headtube.

5) You need a front wheel cause the first gen SV's will not work with those GSXR forks. (SV1000 front will work though)

6) Valving/springs that's all up to you. If you want em perfect for you send them to someone who does suspension.

HTH and GL

Here's a pic of my similar setup that I've been putting together.

2004 GSXR 1000 legs/lower triple
2005 GSXR 1000 top triple
2002 GSXR 750 front wheel
2004 R1 calipers/master

older GSXR 320mm Brembo rotors.
 
#438 ·
This is going to be a vague question, I know, but I received a GSXR front end when I bought my bike used. The previous owner included everything but the wheel, my only issue is I have no idea what year this front end is. It is silver on silver and RSU but I can't find any real identifying marks on the front end itself. Is there anything I could look for before trying to buy a wheel that may not fit. Also the calipers are 4 pots, not radial.
 
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