If you are how many layers and what weight cloth are you using?
I use 1 nice layer of carbon for the look 5.7oz, next scrap pieces on a 45 to the first, then a layer of carbon/kevlar works good to hold thing’s when a oop’s happens so 3.
The kevlar is the key if you want it to hold and not shatter in a crash a safty thing for me. I went off turn 1-2 at Nelson’s Ledges(around 9-10k in 4th so fast) last month and the bodywork held up great. But the set I had on the Kevlar/ carbon was the 1st. layer, so I dont know if the order of the layers will make a big change. The side panel I used silmar 249 and it did not do well its basicly a wet noodle now. the belly pan was VER and cracked but no panel lost pieces with the kevlar.
Most common race plastic is made with a a very few layers of light CSM, and a final layer of light plain weave glass cloth.
Main reason for this method of construction is its not costly, so parts can be replaced in the event of a crash without spending a great deal of money
I use 1 nice layer of carbon for the look 5.7oz, next scrap pieces on a 45 to the first, then a layer of carbon/kevlar works good to hold thing’s when a oop’s happens so 3.
What is the end thickness of your panels?
I make bike parts too but I stay away from full out body kits. There are too many people making them for way too little money.
In any case I know from all the race bodywork Ive fixed in all of my racing days that the good stuff is usually 3-5 layers of 6-9oz (your choices obviously) plain weave e-glass.
The real trick to keeping it from shattering is to make it “dry” as possible. Its pretty hard to make an infusable complete upper mold as the flange area is tricky.
So you have to be very sparing and know your shizit to lay it up.
Then you have to select the right resin…alot of places claim to use epoxy but I call B.S. on that as Ive fixed way too much of it with polyester to know that it shouldnt be able to stick very well.
What resins they use that are that flexible I dont know and I gather its the most closely gaurded “secret” they have.
Like classic bike said, the “old” way of doing it was to use chopped strand matt and a single layer of weave…those days are pretty over except for a couple companies (Beasley and AirTech come to mind) and they are not favored at all anymore due to the hard to unrepairable nature of it along with the weight penalty.
That style of composite bodywork does have its place though.
Most of the common race bodywork available here in the UK is made using poly resin systems, which simply has flex additive in the resin mix.
Works teams such as Crescent Suzuki often use full carbon bodywork, and will buy numerous sets at the beginning of a season… which is obviously pretty costly!
Have repaired plenty of poly resin/csm bodywork, but can see it may well be problematic doing this type of work using the RTM process.
Yeah when I worked for kawasaki I got my first look at composites as we had our own composite shop.
I didnt quite understand what it was that they were doing but I could make repairs trackside if needed.
We had several sets of painted and ready bodywork per motorcycle. Everything was fit to fit any other panel we had for that bike as well.
Ive fixed some of the CSM stuff and to be honest I dont care for it. It really likes to delaminate on you in crashes and makes for the repair almost to be as much work as making another set so the customer may as well as save the money being he is paying for a new set that is heavier and repaired.
Ill have to ask about a flex additive…there are others on the sight…cough cough cheetah jeremy cough cough that work on body kits all day but I doubt hell tell you what resin to use.
I do remember he said something about it taking 24 hours to cure though…dont know anything about it.
I have typed many times about PER flex additive as I use it in my Nascar / oval track stock car racing body panels where rubbin is racin!
The main reason most race bodywork is made cheaply using CSM and poly resin, is so it can be thrown away after suffering crash damage and replaced.
Works teams and more serious racers generally use carbon or carbon/kevlar bodywork, which again is mostly thrown away after suffering crash damage…some might get repaired, but general thinking it that crash damaged composite parts are toast for race use.
My stuff is .050 using VIP.
For race stuff I would use the flex stuff if you can get your hands on some, but the VER with MF-104 catalist I got from Michigan Fiberglass worked fine for me (2hr post cure at 130 F). I’m no pro, just thought I would pass along the info I got from the damage after my comicazi ground hog hunting 
With the shinny street parts the durability of the panel is not as big of a deal to me once you drop it, the look is most likely trashed anyway.
For FZ1gpt
Any chance (if you haven’t already) you can take us through what you did to the fuel tank on the bike in the picture please? I did a search and noticed you mentioned an overlay on the tank of your race bike. Is this the same one? If possible could you post some more pictures of it please?
FZ1Pilot… that lowside incident picture looks like it bent a frame/engine mount? Did your helmet pick up as much grass 
Very nice bike and composites btw
for me a noob…what is “CSM and then VER” I’m just learning this stuff so bear with me please
chopped strand mat (CSM)
vinyl ester resin (VER)
thanks again! Is it ok to use epoxy instead of resin for laying up fiberglass? or is it just overkill since the part would be painted anyhow?
FZ1Pilot…gave me an idea on how to fabricate a composite fuel tank for race only purposes. not my bike though.
well epoxy is a resin, we are talking about laminating epoxy not like table top epoxy. You can use epoxy with fiberglass fabric just not with the CSM because it does not break up the binders that hold the fiberglass together. epoxy has the best structual and strength properties
My opinion…its a motorcycle and its body work. So unless youre trying to make a composite subframe…ITS WAY OVERKILL!
FZ’s tank is an overlay.
Building a complete tank is a bastard that even I dont want anything to do with yet.
CSM will work with epoxy resin systems, but you must use powder bound CSM, rather than what is generally suppled for use with poly resin systems.
LOL I’m still finding blades of grass.
The tank on that bike is a overlay and not a very good one (was my first), used the normal overlay process, lay on resin let it tack up then apply the fabric followed by more resin. There are a number of posts on overlays.