Kevlar/ Carbonfiber gas tank

[Nate_R]

I am thinking about making a prototype Kevlar/ Carbon fiber

gas tank for the WR/yz 450. The stock wr tank is just over 5 lbs dry. I 'm thinking mine will weigh around 2 lbs and will be roughly 2-3 gal. capacity. It will carry the gas really low on the bike for an extremely low center of gravity. I will also be redoing the airbox out of carbon fiber, getting a custom air filter, and moving the air filter up to where the battery used to be. Below the air filter I will put an auxiliary fuel tank of around 1/2 to 3/4 gal. It will use a small 12 v fuel pump to pump the fuel into the main tank when it is low. This setup should be extremely versatile. For long rides full fuel capacity could be around 4 gal. For track riding or short rides I would only run 1 gal that would be carried as low as possible ( but still above the carbeurator) for a really light feeling bike. The most important thing is to carry the fuel as low as possible on the bike. I think this is a good idea but would like to hear other peoples opinions and ideas. I am always looking to improve things and build new things. You never know what you'll come up with.

[Indy_WR450]

Talk to Unabiker here on the TT forum. He has a web site: www.unabiker.com and he can tell you what it is like to work with Carbon fiber. He may be interested in quoting you a tank? He has a lot of experience in this area. Good luck. ?

[Nate_R]

Thanks for the link. I'll check it out. I've been studying up on working with kevlar/carbon fiber. It seems pretty easy. This link http://www.mci.i12.com/carbon/lost_foam.htm shows a guy who made a carbonfiber tank for a bullit bike. Looks pretty sweet. He seems to have a lot of good ideas for working with carbonfiber. The way he did it is really easy. He just took some blue insulation foam, stacked and glued it in a block and carved the tank shape. Then he wraped the carbonfiber around the foam. After it cured he cut a hole in the top and poured some acetone or some crap inside which disolved the foam. Very cool.

[Nate_R]

[r_dawg1021]

I'm not the sharpest tool in the shed but a carbon fibre tank, why? I would rather drop 5 lbs jogging than spend $1k on a carbon tank that'll crack the first time I go down. Are you building a show bike or are you planning on actually riding? Not trying to be a punk but I don't get it.

Street bikes are ideal for carbon but in my opinion it's a waste on a dirt bike. ?

[Nate_R]

If the tank is built right it will be ALOT stronger than the stock plastic tank and it would take alot more to break it than the stock one. It will cost no where near $1000 to build. On the high side it might be $200 in materials. By using a kevlar/carbonfiber weave you get the best of both fabrics. The strength and light weight of carbon fiber and the durability of kevlar. ( Many of the toughest Kayaks in the world are made of kevlar and they smack rocks in the water all day long!) That being said I think it makes a lot of sense. Also, ya you can loose 5 lbs. losing body weight

is not the same as making a bike lighter. The equivalent of what you are trying to say would be going to the gym and gaining strenth, particularly upper body strength. Then the bike would feel lighter cause you are stronger. I am doing this as well, but making a bike as light as you can has many benefits. The most important thing IMO in lightening a bike is removing top weight. So basicaly all I'm saying is there is no question as to whether this makes sense. It makes alot of sense and will yield superior results to the stock setup with little, and probaly no compromise. I think its more of a question of is it worth my time to build and do I really NEED it. I have answered yes to both of these questions already. Now I just need the best ideas and some creative thinking to make it happen.

[ChuckV]

I'm not the sharpest tool in the shed but a carbon fibre tank, why? I would rather drop 5 lbs jogging than spend $1k on a carbon tank that'll crack the first time I go down. Are you building a show bike or are you planning on actually riding? Not trying to be a punk but I don't get it.

I think that the dawg said it here. Carbon fiber is for posers (unless you are a very elite poser).

Lose the 5 lbs, gain some upper body strength and save the money for chains, sprockets, and tires.

?

Chuck

[Nate_R]

It's funny how many companies are using carbon fiber for skid plates and such. I'm pretty sure they dont break with the first rock that hits them. Kevlar has great impact resitance and by combining the two in a weave you get an incredibly stong material. Unfortunately most people don't want or need to spend the kind of money manufacturers would demand for composites. It is expensive to buy from some one who manufactures composites, but I can make stuff my self for less than I could buy the same thing made out of aluminum, or whatever. So in my aplication I think it makes more sense for me to make my own tank than to go buy say an IMS tank for $200 that would not meet the criteria for what I want on my bike, performance wise.

[Nate_R]

I think that the dawg said it here. Carbon fiber is for posers (unless you are a very elite poser).

Lose the 5 lbs, gain some upper body strength and save the money for chains, sprockets, and tires.

?

Chuck

Thats a really Ignorant statement dude. You might want to do some research on the subject so you can be better informed on the physical properties of materials. I am all about riding ( perfomance in particular) and don't just settle for whatever manufactures deem is an acceptable part.

There can always be and always is somthing better. I don't see you guys riding around on 1978 enduro's. Technology should be taken advantage of. Before you start calling people posers do some research on materials and come to your own conclusion what would be the best material to build a tank out of. BTW, All the worlds brightest innovators were slammed, criticised, and called names. Yet they Innovated. ( Not that I necessarily fit into their category)

[ChuckV]

Unfortunately most people don't want or need to spend the kind of money manufacturers would demand for composites. It is expensive to buy from some one who manufactures composites, but I can make stuff my self for less than I could buy the same thing made out of aluminum, or whatever.

Nate, you hit the nail on the head. If you have some knowledge and abilty (or even interest), then work with the carbon fiber. I would love to experiment and share what I find likewise. I don't subscribe to buying from someone because it is lighter.

Chuck ?

[ChuckV]

?Thats a really Ignorant statement dude. You might want to do some research on the subject so you can be better informed on the physical properties of materials. I am all about riding ( perfomance in particular) and don't just settle for whatever manufactures deem is an acceptable part.

Whoa man, I wasn't attacking you ?, I was stating an OPINION . I agree with experimenting with materials. I would love to learn more about lighter and stronger stuff to fabricate with. I disagree with buying the unobtanium from companies who market it to posers. I wasn't calling you a poser...

Regards,

Chuck

[Nate_R]

True. There are a lot of gimmicks out there and there are alot of "posers" that are misinformed and just follow fads. This however should not discredit somthing that is outstanding. The reason I want a lighter bike is it has a lot of advantages. Some people don't need a light bike and

just want to ride. That is cool. I respect people like that and they have tons of fun with what they have. Me however,

I have a gift and a curse. I love building things and coming up with new ideas and products that can enhance my life experience. I find that riding a lighter bike is more fun, you can do more, you can ride longer, it handles better, wont break as easy, etc. etc. Sometimes I do get carried away and have to take a few steps back and rethink what I'm doing. I could just go out and buy a light weight 250 2 stroke, but thats not what I want. What I want does not exist. I have to attempt to build it. Some time in the near future I can see myself building a custom dirtbike kinda how the boys over at OCC build choppers. I'll get all the parts that would not be cost or time effective to make my self ( wheels, motor, brakes, etc.) and build a frame around them.

Me and a buddy engineer of mine are messing around with a few ideas on air sprung forks and shocks that we will build soon. There is always room for failure, but it's pretty amazing when you build something and it works! ?

[Nate_R]

In that case, chuck I apologize and retract my statement. I missunderstood what you were saying. Right you are about them tards marketing unobtainium to posers. Being a mountainbiker I see a lot of suckers throw away lots of money on crap that is a gimmic. But, lighter IS usually better, as long as there are no compromises and it is built correctly, IMO. ?

[ChuckV]

In that case, chuck I apologize and retract my statement. I missunderstood what you were saying. Right you are about them tards marketing unobtainium to posers. Being a mountainbiker I see a lot of suckers throw away lots of money on crap that is a gimmic. But, lighter IS usually better, as long as there are no compromises and it is built correctly, IMO.

Nuff said? ?

:thumbsup:Chuck

[Nate_R]

Here is a description of kevlar I found on a kayak website:

"Thanks to the US space program, we have Kevlar as a kayak building material. Kevlar kayaks are stiff, lightweight, yet extremely tough, and expensive.

Kevlar is the stuff bulletproof vests and flak jackets are made of. Kevlar is slightly less stiff than fiberglass, but much tougher and lighter weight. Kevlar kayaks are made in the same manner as fiberglass and carbon fiber kayaks. Often, a little fiberglass or carbon fiber will be combined with the Kevlar cloth in a kayak to give a little added stiffness.

Kayaks constructed from kevlar are very, very tough. Because the fiber itself is so flexible, the kayak will absorb a serious impact and spring back. A collision with a rock that would hole a fiberglass or carbon boat might result in only cracked gelcoat on a Kevlar kayak.

Kevlar fibers are very tough, and difficult to sand or cut, so repairs are slightly more difficult than fiberglass."

A kevlar gas tank ain't gonna break. I'll probably try making all my bikes plastic out of kevlar and see how "impact resistant" it is. The cool thing about it is you don't have to have the "carbon fiber look". You can add

pigments of just about any color to make it whatever color you want.

[mousemeat]

Are you going to do it with wet epoxy or pre-preg? Pre-preg would be alot better as far as surface finish goes, but you need access to a vacuum pump and at least an oven, but an autoclave would be better. Also i'm not sure about finding a foam that will hold up to autoclave temperatures which is also easily dissolvable. On the other hand, wet stuff takes quite a bit of practice to look good, but if you are going to paint it, then that wont matter.

I would just use a plain carbon weave. Aramid fibers are nice and tough, but that wont do you much good within an epoxy matrix. Basically, toughness will help you out if you are looking to absorb alot of energy as it gets destroyed, so it might be a good material for the hood of a car, but if your tank gets crushed, that is of little concern. Carbon is stiffer than kevlar, which is going to be your primary concern. Make sure the epoxy you get will hold up to petrol in the long term. As for the carbon you get, T300 seems to be the best deal. That said, there is a worldwide shortage of carbon fiber at the moment, but that shouldnt effect such a small project.

I wouldnt make fenders out of carbon. The stiffness of a plastic or carbon fender is insignificant in even a mild crash. They will deflect as much as the momentum of the bike and the hardness of the ground tell them to. Plastic will bend out of the way, carbon will break into a million sharp little pieces. As you can probably tell, i like my carbon stuff, but the uses on a dirt bike are very limited. Fot the street, i'd make the whole lot out of carbon. For offroad stuff i would limit carbon usage to gas tank, airbox, frame guards, sump guard/skidplate, and if you are feeling really brave, the rims. Radiator braces and luvers(sp?) might be cool as well.

The only reason i can see composites not being a good material for a petrol tank is if in a crash it splits the epoxy, fuel comes out and pours over your header. Things might get pretty bad pretty quick.

Good luck.

[r_dawg1021]

If the tank is built right it will be ALOT stronger than the stock plastic tank and it would take alot more to break it than the stock one. It will cost no where near $1000 to build. On the high side it might be $200 in materials. By using a kevlar/carbonfiber weave you get the best of both fabrics. The strength and light weight of carbon fiber and the durability of kevlar. ( Many of the toughest Kayaks in the world are made of kevlar and they smack rocks in the water all day long!) That being said I think it makes a lot of sense. Also, ya you can loose 5 lbs. losing body weight

is not the same as making a bike lighter. The equivalent of what you are trying to say would be going to the gym and gaining strenth, particularly upper body strength. Then the bike would feel lighter cause you are stronger. I am doing this as well, but making a bike as light as you can has many benefits. The most important thing IMO in lightening a bike is removing top weight. So basicaly all I'm saying is there is no question as to whether this makes sense. It makes alot of sense and will yield superior results to the stock setup with little, and probaly no compromise. I think its more of a question of is it worth my time to build and do I really NEED it. I have answered yes to both of these questions already. Now I just need the best ideas and some creative thinking to make it happen.

I guess it all comes down to what your goal is. Is it to make the bike lighter? If your goal is to make the bike quicker (Horse Power /Weight) ratio than it doesnt matter if the weight comes off you or the bike. So my theory on losing the weight isnt off if you're simply trying to get faster. If you're trying to make the bike lighter for flying through the air and doing tail whips and all that stuff than I could see getting the bike lighter.

I don't know much about Kevlar but I do know Carbon is spendy and that's what I was commenting on. I don't think it's ignorant to call someone a 'Poser' based on historically who puts carbon on their bikes and for what reasons.

[jjk]

Have you considered the physical properties of silly putty?? I think you would be very surprised at how this material might work for your application, and look on the bright side, imagine the cost savings... ?

[Nate_R]

Aramid fibers are nice and tough, but that wont do you much good within an epoxy matrix

I may be misinformed but my understanding is that stiffness is not the primary concern for a tank. I would think that the same ideas would apply to a dirtbike tank that would apply to a kayak. All the tank needs to do is hold fuel securely and be strong and impact resistant so it wont break. Am I way off? Kevlar has more flex and give to it

than carbonfiber so it will spring back upon impact, wheras carbonfiber would shatter, right? For the application of a tank, I'm pretty sure the resulting strength of the tank would far exceed any forces that would ever be exerted upon it. My primary concern would be impact strength , such as a rock hitting it. This is where kevlar exceeds. I think a carbon/ kevlar weave would be ideal because you would get the best of both materials.

As far as finnish goes i'll probably be using pigment for the resin so i don't have to worry about getting fibers looking good.

[simch]

Interesting stuff, and well worth a try IMO, like you say its only a few dollars of materials. But such teachnology may be defuct soon anyway!I know someone in the UK that supplies to the Yamaha Supermotard team. They told me there is a hybrid prototype yZ450 motard with an ally beam frame that contains the fuel, and the oil is in the Swing arm pivot lug!

Would love to see photos,but imagine the possibilities on styling with no fuel tank!! A huge airbox could sit up there, ram air etc!!

I'd agree that to do a real nice job, Nate, you should try to use prepreg and an autoclave. You can make a simple autoclave quite easily, but to have one large enough to make a good job on a tank is a bit more tricky. But even some high quality fibreglass manufacturers use claves now, so you may find one locally to experiment with.

Have you thought about being real trick and fitting internal baffles to save sloshing of fuel and weight transfer?? I understand some of the moto gp bikes have tanks that are like "double glazed" ie insulated, to keep the fuel cooler and thus more dense! As for the integrity of such items (fuel tanks etc) try a few rally or race car suppliers for info on types of material and design/ production specs to ensure its real strong and wont seteriorate with age etc. But if you wanna lose weight carbon / kevlar is the way ahead.

It beats drilling the plastic tank for lightness!!! ?