Building a GS500 race bike

[omrimon]

ey guys,

I'm in the process of acquiring parts to build a race bike based on a GS500 frame and engine, with 05-06 GSXR or 07-08 ZX6R front end and possibly swing arm and rear wheel in order to fit slightly wider tire.

Does anyone have any experience they're willing to share? It would make this project go a lot smoother if I knew before hand what needs to be done or made in order to mate all the parts together.

In particular, I'm wondering which wheel/rotors will fit on a ZXR front end as the front end I fonund doesn't come with a wheel and rotors.


I did find a lot great info on this site but most of it is regarding older GSXR parts which I can't find on ebay.




Thanks in advance!

Omri G.

[ohgood]

you may want to use craigslist and search for katana and sv650 FE's.

there are a couple of really nice write ups of the kat FE swap here on the forum. pictures included. give the search button a try, or berto or one of our other human search engines will chime in with the link in 3, 2, 1....

[Jay_wolf]

http://gstwins.com/gsboard/index.php?topic=13673.0
           Katana F/e

http://gstwins.com/gsboard/index.php?topic=25426.0

Katana Rear Wheel


Sigh... 

[dgyver]

When building a race bike, make sure you know the rules of the classes that you would be racing. There may be limitations that would govern possible modifications.

Remove and cut off as much stuff as possible to lighten the bike.
Motor mods can go from the mild to extreme.
Suspension upgrades will provide the best return for your money.

- The Kat f/e is the easiest upgrade and the least expensive. GSXR can be done, needs a stem swap or modified stem. Most any f/e can be installed.
- The 98+ Kat 4.5" rear wheel is the easiest rear wheel swap with the stock swingarm. Other swingarms can be installed but the GS frame is narrow so this limits the options.
- There has been some discussion on using a 98+ Kat 3.5" front wheel on GS forks. Another forum has shown this is possible but I have yet to confirm this personally. The advantage would be to be able to run a more common 120 front but the disadvantage is there may be a loss of turning ability. The agility of the GS is its strong point.
- The rear shock needs to be upgraded. Once again Katana is a common upgrade. A GSXR shock can be made to fit. I will not go into the details unless needed.
- Ignition advancer is a must. Bob Broussard does the 89-01 rotors.
- Larger bore, 78mm GPZ pistons is the best option, 79mm is the largest you can go with stock sleeve and anything larger will require new sleeves.
- 36mm carbs, smoothbores are the best and most expensive, GSXR carbs can be modified to fit.
- Megacycle Cams will modify stock cams for $266, a good pairing with the 78mm pistons and 36mm carbs.
- High flow air filter, K&N lunchbox RU-2970 is the most common.
- Aftermarket exhaust, Yosh is my favorite but hard to find, cutting off the restrictive stock muffler and welding a different can is a popular option. V&H, Jardine make full systems as well.
- Braided brake lines are a must. Dual front rotors (with the f/e upgrade) make braking fun.
- EBC HH pads up front, I do not care for them in the rear due to locking up, I normally run stock pads or something less aggressive in the rear.
- An electronic tach can be used. I use them from a Katana, wiring is pretty straight forward.
- Ground clearance with stock rearsets will be a problem. Woodcraft makes nice replacements. There other options for modifying rearsets from other bikes.
- Change the clutch lever to a GSXR. Replacement levers are easier to obtain as the GS has a very specific lever.
- A good idea is an aluminum cover for the rotor and signal generator on the right side. Chuck81 makes them. Good crash insurance.

Just a little info to get you started.

[The Buddha]

Newer style GSXR FE is lighter, has the ability to take radial brakes and master cyl etc.
Newer GSXR rear wheel is also very light. they are frail and like made from eggshells ... but they are light.
Cool.
Buddha.

[dgyver]

Newer style GSXR FE is lighter, has the ability to take radial brakes and master cyl etc.
Newer GSXR rear wheel is also very light. they are frail and like made from eggshells ... but they are light.
Cool.
Buddha.

One reason those used wheels carry a high price tag.

[omrimon]

Wow, that's a lot to chew at once. Thanks!

So far, I placed a bid for a complete  07-08 ZX6R front end, minus wheel and rotors. Still have to find either a ZXR wheel or anything else that could be made to fit.

Planning to buy a pair of Woodcraft rearsets, unless some has a better solution that wouldn't require too much mods.

I have a rear shock off a 95 GSXR750 that I put on my Hyosung, do you guys know if it'll fit the GS?

I'm also looking to buy some race fairings, I know nearly any fairing could be made to fit but I'm looking for something that will be rather simple to install, any ideas?

Also, where can I buy one of those ignition advancers online?

Thanks again for all your help!

Om. #420

[dgyver]

Bob B modifies the stock rotor to function the same as the V&H rotor.
http://gstwins.com/gsboard/index.php?topic=13727.0

[Kurlon]

Airtech makes a race fairing kit with mounts, fairly cheap if I remember correctly.

Go with Woodcraft rearsets MADE FOR THE GS500E, many of the others can be adapted but end up putting the pegs lower which doesn't help.

Also, I second checking the class rules FIRST before you spend money.  For Production Twins at NHMS I have to keep just about everything stock for example.

[ben2go]

High performance clutch for a 99 to 02 SV650.I am using mac cycles kevlar friction plates and Barrnett clutch springs.Better have a strong arm for this set up.It's stiff and doesn't allow for any clutch slipage.

[omrimon]

I will be racing in a class where all suspension mods are permitted, but all engine and intake system mods are forbidden.

Mufflers can be changed but stock exhaust system has to be retained.

Full race fairing is required.

The calls is dubbed GP500, where all bike up to 500cc are permitted. So far, five out of six competitors are using GS500's, some stock, some modified. The other guy is using a heavily modified Supermono DRZ400 .
I was planning on racing my Hyosung GT250R but got into an accident on the highway and decided to ditch it for a GS.

Some pics:



89 GSXR front end, GSXR rear wheel with a 180/55 tire, ktm fairings.



DRZ400 with R6 front end, R1 race fairings, modified rearsets and more.


Stock GS500



03 ZX6R front end, RGV swing arm and wheel, GSXR750 race fairings.

[The Buddha]

95 GSXR 750 shock is just about the best shock you can buy for a GS that does not have the word fox, or penske or ohlins in it ... it will also fit without cutting and welding and it will on the street just about be super stiff and like a jack hammer, but a smoother reack type surface it may just be what the doctor ordered (if a doctor ordered you to race that is).

Cool.
Buddha.

[coll0412]

Sounds like a lot of work to race a GS500 there.

My recommendations:

Rock the stock suspension with the usual upgrades(race tech and cartridge emulators). Until you get to be really fast, the stock stuff will be okay. Racing with the CRA, the GS500 has to compete with the Monster 620(15+ more HP and a proper front end). Yet people rocking stock GS500's can still keep up. Remember that its 80% rider, 20% machine. In fact one of the 620's runs a 2:08.7, I run a 2:10.0 on a GS, and the fastest guy last weekend ran a 2:04 on a GS.

Look for a wheel swap so you can run some decent rubber, that makes life alot easier.

I have seen everything under the sun fitted to the GS. 98-03 R6 fairings, Ducuti 996, find something thats cheap and start there..lol

Woodcraft rearsets are the way to go!

Buys some dang good leathers and safety gear with the rest of your money.

[omrimon]

Does anybody know which wheels might fit in a 92-93 GSXR 600 swingarm that won't involve too much cutting and grinfing ?

Also, does anybody know if a 95 GSXR 750 shock would/should fit in the swingarm mentioned above. As little mods as possible as well.?

Lastly, would the stock caliper fit onto the 93 swingarm?

Cheers.

[werase643]

suggestion......
a Kaw EX500 is 498cc and about 15-20 hp more....stock
with zx6 front and a F3 rear wheel....you would have a better chance

DO NOT USE THE STOCK GS FRONT END
you will have to replace the front rotor often due to overheating
the single disc is not good for racing
easiest front end swap.... RGV-250.....sweet and light.....bolt on

[omrimon]

suggestion......
a Kaw EX500 is 498cc and about 15-20 hp more....stock
with zx6 front and a F3 rear wheel....you would have a better chance

DO NOT USE THE STOCK GS FRONT END
you will have to replace the front rotor often due to overheating
the single disc is not good for racing
easiest front end swap.... RGV-250.....sweet and light.....bolt on

I've been considering the ER500 but GS's are easier to find. Plus five out of six competitors are using the GS's.

So far, I bought a 03 GSXR1000 front end and woodcradt rearsets.

Still considering a complete RGV rear end swap or just a Katana or GSXR rear wheel in order to put on some decent rubber.

[PortlandGSFloger]

anyone know if the 96 Katana wheel will fit in the stock swingarm? also is this a 4.5 inch wheel?

[The Buddha]

Not 96, 98 and later, I have one off 02 in silver, $125 and it will drop in.
Cool.
Buddha.

[intergalactic]

doesn't dgyver have a RGV swingarm for sale? Shipping to Israel is probably $3. 

[jrains89]

so you can't rejet or anything? I don't really know how they would tell unless they make you take them out and show them. or at least shim the needles to give you better throttle response and midrange.