Figured I'd start a post covering my build progress on my 93 GS500E as I turn it into a proper road race machine.

For those unfamiliar with the 'Production Twins' class run by LRRS at Loudon NH, in a nutshell it's production bike racing for two cylinder machines, 650cc air cooled, 500cc liquid.  The dominant machine by sheer numbers is the venerable EX500.  Occasionally someone will show up with a Ducati 620 Monster or Supersport, but thats rare.  For 'mods' I'm allowed to respring and add emulators up front, and replace the rear shock.  After that, I'm only allowed safety modifications, so turns signals are to be removed, safety wire, etc.  I have to retain the stock headlight bucket (Need to see if I can gut it though.) and stock exhaust.  I'm allowed to update and backdate within the model run, and I've already cleared using GS500F parts as it's essentially the same bike.

The victim in this case is a 1993 GS500E I purchased from a friend.  She bought it as a learner machine, used it for a couple years, and finally gave up on it when it started eating coils like candy.  I don't know it's prior history.

When I got it, it had clubmans installed backwards so they resembled standard bars, one coil was bad.  Further diagnosis found one side of the CDI was shot, as was the regulator/rectifier, which I think started the bike's electrical woes.  A little ebay work later I had a new CDI, a generic regulator/rectifier has my charging system sorted.  The clubmans aren't wide enough to clear the upper clamp when I tried mounting them correctly, so then end up being rotated to far back, completely impractical.  I still rode it to work to see how it went, and other than killing my wrists, the only observed issues were almost non-existent brakes, carbs could use a good cleaning, and when warm there is a slight knock from the head.  Oh, and it has classic GS500 weeping head gasket syndrome.

The bike has since sat, as I haven't had time to work on it, or space given the horrendous weather we've had.  I have been busy in other ways though...

I bought a set of used Woodcraft rearsets, indirectly through a member of the forum.  (l3uddha bought them and then sold them to me after buying a Triumph.)  Not finding any deals on clipons, I went ahead and bought a set of Woodcrafts new.  EBC HH pads are on order, as is a new front rotor.  Suspension bits will be on order shortly, Works in back, Racetech up front.

I need to find a new(er) set of forks, or at least upper tubes, as mine are pitting.  I'd like to find an F exhaust system as they are reputed to have larger headers than the E's.  Plus I need to invest in safety wire and drill bits... lots and lots of drilling and wiring to do.

My first opportunity to run the bike on the track is April 15th, so things are going to be going nuts for me shortly... : )  I'll try and get pics as I go.

Spoke to David Johnson via email, I've now got a couple additional items to track down, a good fork brace (I see one in the For Sale section) and a 96 or later front caliper.  Add a set of preload adjusters for the forks, and I should be in good shape.

Are you allowed to rejet the carbs and add a K&N lunchbox?

I can rejet, but I have to retain the stock airbox and filter.

You can always richen it up and blind them with the black smoke. 

Quote from: Kurlon on March 10, 2008, 06:21:54 PM
I can rejet, but I have to retain the stock airbox and filter.

Stock airbox with drop in OEM replacement Air filter.... like a K&N drop in minus restrictor plug 

Awesome, I'm looking forward to the progress

I heard Loudon is a crazy track...something about a bowl which has you looking up over your shoulder as you round the turn?

Quote from: badguy on March 11, 2008, 09:36:08 AMI heard Loudon is a crazy track...something about a bowl which has you looking up over your shoulder as you round the turn?

Yup, 'the bowl' is a near 180 degree banked turn.  You enter it coming down hill at a good 15% grade or so, aiming to be moving left, crossing the middle of the track as you enter the turn.  Then it's a hard left, down the side of the track into the middle of the turn, at which point you start looking up, about at the limit of how far your helmet will let you crank your head back as you climb up a new, sligthly steeper grade than you came down in on as you complete the second half of the turn, throttle up the hill for a lil kick right, then back down the hill for a fun 90 right that brings you back onto the NASCAR oval. : )

Looks like a weird line on paper, feels incredible the first time you get it somewhat right, you can carry crazy speed though it with the right line.  Given my competition has 10hp on me on average, thats one of the areas I hope the GS's superior geometry gives me an edge, along with the few hard braking points.  (EXs have the same caliper as the pre 96 GSs, so by upgrading I can run better pads, and have more contact area, so I should be able to late brake them if I grow big enough stones...)

Fork brace and rotor covered on their way from a forum member.  Still gotta do a bit more research on the E to F exhaust swap and if it'll actually net me anything.

Sounds like fun!  Keep us posted.   

I'd like to hear more about how the class is set up, costs and whatnot.  Unfortunately though, I'm too far away to play.   

Who runs the local series in your area?  I know WERA has a bunch of GS500s running around, and they're allowed more leeway in their builds compared to PTwins in NH.

Quote from: Kurlon on March 10, 2008, 06:21:54 PM
I can rejet, but I have to retain the stock airbox and filter.

I've got a unifoam if you can run that that I'll sell you cheap.

Fork brace and rotor inspection cover arrived, both are billet art.

I also have a new 'todo' item to investigate for the build... frame sliders.  One person racing in WERA has mounted a set on the main frame rails, right under the tank.  Looks like he found a spot where he could put in a cross brace between the rails... looks slick and the report is it worked well the one time the bike was down.

A new caliper (96+ style) is on order, new rotor arrived from EBC and it looks killer.

I need to settle on engine guards too, completely spaced on those.

Bombadillo: I dunno how strict they're going to be on filters yet, so for now I'm going to put a new OEM unit in I think.

Does the air filter have to have the paper element in it?

One thing about the exhaust... grind out the weld on the inside of the header at the mounting flange at the head. I removed at least 1/16" on the ID on each of mine. It may not be much but any extra flow would help.

Quote from: Kurlon on March 18, 2008, 10:49:30 AM
Fork brace and rotor inspection cover arrived, both are billet art.

I also have a new 'todo' item to investigate for the build... frame sliders.  One person racing in WERA has mounted a set on the main frame rails, right under the tank.  Looks like he found a spot where he could put in a cross brace between the rails... looks slick and the report is it worked well the one time the bike was down.

A new caliper (96+ style) is on order, new rotor arrived from EBC and it looks killer.

I need to settle on engine guards too, completely spaced on those.

Bombadillo: I dunno how strict they're going to be on filters yet, so for now I'm going to put a new OEM unit in I think.

For case guards check out http://www.mcenterprises.com/ for a set for $40. They work great, and are a steal at $40.

I want pics. 

No pics till it's at least de-greased. : )

If the weather cooperates, it comes out of storage Saturday for a quick trip to the local car detailer.  It'll get a quick cleaning with a heated pressure washer, then back to the shop for an eval session.  I'll try to get some pics if all goes to plan to show you the 'before' condition.

Be super carefull with the pressure washer, alot of the bearings are not sealed enough to prevent high pressure water from getting in there.

Lovely, thanks for the heads up!  I'm hoping that the heat will do the majority of the work rather than relying on the pressure, but we'll see what happens.

http://www.x386.net/TTR/media/GS500E/032208-Initial_Build/HPIM0360.JPG
http://www.x386.net/TTR/media/GS500E/032208-Initial_Build/HPIM0361.JPG

As promised, pics.  This is just after cleaning it today.  Spotted two things of interest; the front rotor is an EBC unit, and someone rigged their own chain guard out of metal... thats going to go.

Oh, and I'm missing the left hand Suzuki emblem.  I'm half tempted to get a big round puck of Delrin and bolt it in place instead...