The making of a race bike
Stephen's '97 EX500 project bike in detail.
Well since I've decide to start racing an EX500 this year I've been real busy. I traded all of my remaining FZR600 parts for a wrecked EX500. When I took delivery of the bike it looked pretty bad as you can see 
for yourself. You note in the background the ZX600R swingarm that will be fitted to the frame. I was going to use that RD60 gas tank on it, but I've decided to use a hawk tank instead. The first thing I had to do with the bike is strengthen the frame to the extent that is allowed under CCS rules. As I interpret the rules I have to have the stock frame & engine cases from a EX500. I am allowed to gusset the existing frame, but I cannot alter the stock suspension mounting points. What I really wanted to to was build a frame that had a shorter wheel base, more competitive steering geometry, and more forward weight bias than the stock frame. Well I can't do that and be legal for lightweight sportsman. I can strengthen the existing frame per the rules.
In order to stiffen the stock frame I first installed a set of solid engine mounts to replace the stock rubber ones. Rich, my teammate, had a extra set, but unfortunately the interference fit was so tight that I'm afraid they will never come out. I'll need to buy an extra set for the "A" motor, more on that later. Anyway solid motor mounts make the engine a stressed member within the frame, and tie the lower half of the frame together quite nicely. The next area that needs to be address is the upper half of the frame. I welded in two trusses between the upper frame members. The first one is closer to the steering head 
and is triangulated nicely. Here is a view from the opposite direction 
of the same truss. Behind that truss I welded in another one 
that is cut to clear the top of the valve cover. As you can see I'm not sure I'll not be able to check valve clearances with the motor in the frame, but then again this is a race bike. Also, since this is a race bike I've also eliminated most of the sub-frame and re-welded 
a section of it for the solo seat. I'm going to use a '87 FZR1000 solo section, not because I like it, but because I have it. I actually did that before I did the truss work in the upper frame, that's why you don't see in the picture. The work took longer than I thought because; I have a crappie 110v buzz box stick welder
, I am a poor welder, & I have to run beads on both sides of everything I do. I've cut into some of my test welds on the hacked off subrame and they are big gloppy messes, but there is full penetration. I feel they are safe to race on Here is a action shot 
of the front truss going in. It is a involved process, but one that anybody could do. I got the welder as a trade for a lawn mower I got for free that was not running. One like it sell for about $150.
The upper trusses came out pretty good. 
Note the collar between the front engine mounts. That's the stock swingarm pivot bushing that is about exactly the width of the engine cases at the front mount. I've put it there to help keep warping to a minim during the welding. Still I'm going to have to straighten the frame when I've done.
After the upper trusses were done I turned my attention to the lower frame rails. I've made a bolt off bracket to triangulate the lower rails. It has to bolt off because the righthand frame lower has to be removed to take the engine out of the frame. Here is a picture of the mounting point 
that is a modified radiator attachment. As you can see I welded flat stock to the sides & the frame downtube itself. Not as strong as if I did it directly to the frame, but I have to clear the exhaust pipes and keep the brace in plane with the area below the steering stem. From here I attached a bolt off piece to which the cross members would be welded. The crossmembers would bolt to the opposite side of the area underneath the steering stem.
. As you can see this should support the lower section together 
, this is viewed from the top. The finished product looked like this
.
I picked up a Fox shock for a '92-'93 GSXR600's, and '93-'95 GSXR750's. It has what appears to be a Fox part number of "97-2037". The shock has adjustable ride height. To re-cap the modification that I HAD to do to get it to work;
1) Can the Fox 7.5x???#500 spring for a 7.0x2.25#300 spring made by Ibach that was obtained from the race car supplier Total Choice for a cost of $25. (actually the cost was suppose to be $50 for one, but they sent two springs..:-)
2) Remove the Fox bushings spacers for the top mount & replace same with stock FZR units to accept the 10mm upper mount bolt. In a pinch you could use washers to shim side to side movement as the Fox bushing is 10mm. Its interesting the Fox made spacers for a 10mm bushing instead of just using a 8mm bushing for the Suz equipment.
3) Replace the "C" bracket that attaches the Fox shock to the linkage with one that will clear the linkage casting when the suspension is compressed. I used the stock EX500 shock "C" bracket. To attach same I had Forrest Kerns turn a piece of round stock that was threaded on one side with the threads of the Fox shock, and with the threads of the stock EX500 shock "C" bracket on the other side. This about doubles the range of adjustability over what Fox's "C" bracket allowed. The shock can now go from about 12 & 1/8 inches to about 13 & 3/4 inches, more than I'll ever need. Forrest charged me $20.
3) Grind a small (about 2.5mm) divit in the top of the linkage to clear the ride height adjusting rod if you want lowest possible ride height. I have found that this was not necessary as I have only gone up with ride height since installation & clearance is no longer an issue.
4) Drill the lock nuts & the ride height adjustment rod for safety wire as unlike the Fox setup it is possible to have the ride height adjustment rod back out while riding it.
5) Grind a small area on the backside of the shock to clear the frame bracket on the upper shock mount. Took about two minutes with a diegrinder.
Well thats it for the frame for now. Later I will welding a truss on right and left sides between the upper and lower frame rails, with the right and one being a bolt off affair. I'll post picture when they are done. The motor is going to be stock for now, but we are just looking at the numbers for a stroker. I'll post more pictures of same when there are done.
Check out the motor analysis we're looking at.
Back to the Team Charm home page.
for yourself. You note in the background the ZX600R swingarm that will be fitted to the frame. I was going to use that RD60 gas tank on it, but I've decided to use a hawk tank instead. The first thing I had to do with the bike is strengthen the frame to the extent that is allowed under CCS rules. As I interpret the rules I have to have the stock frame & engine cases from a EX500. I am allowed to gusset the existing frame, but I cannot alter the stock suspension mounting points. What I really wanted to to was build a frame that had a shorter wheel base, more competitive steering geometry, and more forward weight bias than the stock frame. Well I can't do that and be legal for lightweight sportsman. I can strengthen the existing frame per the rules. 
