Carbonfiber frame modification

Does your Spree/Elite already run great, and you're trying to make it quicker/faster? Need a monster motor swap? Discuss your ideas here.

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elitedio
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Carbonfiber frame modification

Post by elitedio »

I've thought about how to make the Elite E's frame stiffer. My bike will go 60+ as it is set up now. There is some obvious flex going on, the handlebars do have some fore-aft and some lateral flex at higher speeds, above 45 mph. My suspension units are stock so they probably need to be upgraded but for certain the frame is not up to the task. My wife is the main rider and she has mentioned the flex.

The obvious solution was to put a brace between the headset and the engine cradle. I thought it might lose some utility and preventing the case of beer from being carried between the feet.

Our plan is to stiffen the frame by wrapping it with carbon fiber. We have done this on other projects.

The materials we used were carbon fiber cloth, fiberglass cloth, West system epoxy, Super 77 spray glue, acetone, Dacron (polyester) fabric.

Started by removing the plastic and moving wires and cables aside. Wrapped duct tape over areas around headset. Wiped frame down with acetone. My wife did the majority of the work with myself keeping my hands clean to photograph the progress.
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Sprayed the frame areas with Super 77.
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Stuck down a layer of fiberglass to prevent galvanic reaction between the steel frame and the carbon fiber.
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Sprayed the fiberglass with Super77 and glued down 2 layers of carbon fiber (3 layers at the bend). We then lashed the carbon cloth with carbon thread to hold it closer to frame. Only then did we wet the areas with the West system epoxy.
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At this point it is quite a sticky mess.

The next step was to wrap the frame with the polyester and ripstop nylon cloth tapes that we made by tearing the cloth into 2" wide strips. The polyester is not very strong but it does shrink when you use a heat gun.
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Compressing the layers is an important part of the process. The epoxy doesn't have nearly the strength of the carbon we want to compress the fibers close together.
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Once cured the cloth layers will be peeled off of the carbon fiber and two more layers of carbon will be applied directly over the carbon now in place and the process repeated.

We intend to make the carbon about .125" thick on the top and bottom of the bend in the main tube and around the head set. I am not an engineer but it should double or triple the stiffness of the front of the frame.

This is one of those modifications that doesn't make the bike accelerate any faster or make the bike look cooler, but it should make it handle better and be safer.
1989 Elite E with 86cc Dio
Rumia 50mm bore, mini-stroker, 28mm Oko, modified m-x pipe, Carbonfiber reinforced frame.

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http://www.youtube.com/watch?v=gKSvdjxvBUA
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akskoot
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Re: Carbonfiber frame modification

Post by akskoot »

that's really cool. i hope it helps. :coolcruise:
1985 Aero 50--'87 AF05 motor, ported and polished, Ruckus Vari, 1.5K torque spring, 1K clutch springs, drilled exhaust/airbox,#85 jet, Pirelli 3.0-10s= 45mph flat
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elitedio
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Re: Carbonfiber frame modification

Post by elitedio »

We got the fabric peeled from the carbon, the carbon is about .070" thick. Next step is to add a more layers on critical spots like the head tube junction and at the big bend and where the tube meets the sheet metal rear sub frame.
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The finish is perfect for adding more carbon. The impression left by the fabric allows the secondary layer to bond well the primary layer.
1989 Elite E with 86cc Dio
Rumia 50mm bore, mini-stroker, 28mm Oko, modified m-x pipe, Carbonfiber reinforced frame.

Image
http://www.youtube.com/watch?v=gKSvdjxvBUA
Fishman43
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Re: Carbonfiber frame modification

Post by Fishman43 »

Interesting, I always thought carbon fiber was more flexable than steel. I seem to rember a bike friend telling me that about carbon fiber bike forks.
elitedio
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Re: Carbonfiber frame modification

Post by elitedio »

Fishman, I think you are right about carbon being more flexible than steel.

It can be very stiff however. Young's modulus shows Carbon is 125-150 and steel is 200. (For comparison other materials are: fiberglass 40, aluminum 70 and Kevlar 100.) We've added another .1" wall thickness over the standard frame material. Carbon weighs about 1/4th the weight of steel.

What I don't like about carbon is that it is rather brittle when compared to steel. It doesn't have the toughness. It is not a problem in this application because the steel frame of the scooter is providing the toughness.

There may be other factors but this is how I look at it. We have made our own carbon recumbent bicycles and fairings in the past.
1989 Elite E with 86cc Dio
Rumia 50mm bore, mini-stroker, 28mm Oko, modified m-x pipe, Carbonfiber reinforced frame.

Image
http://www.youtube.com/watch?v=gKSvdjxvBUA
elitedio
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Re: Carbonfiber frame modification

Post by elitedio »

The frame is cured enough on the secondary layup to remove the fabric. I measured the overall diameter and have .129" of carbon over the main bend and a bit more around the headset area. The back was reinforced with several layers on the rear frame area.
Image
The white spiral lines that you see in the photo are the edges of the heat shrink fabric and have no effect on the structure. Our man in black "Cash" got in this photo.
1989 Elite E with 86cc Dio
Rumia 50mm bore, mini-stroker, 28mm Oko, modified m-x pipe, Carbonfiber reinforced frame.

Image
http://www.youtube.com/watch?v=gKSvdjxvBUA
mousewheels
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Re: Carbonfiber frame modification

Post by mousewheels »

Thanks - a good trick to reinforce, and keep a stock looking bike. And your process is instructive.
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Re: Carbonfiber frame modification

Post by elitedio »

Mouse, I have tried keeping the method easy enough (low tech) for anyone without equipment. like a welder. I have welders available but wanted to keep it looking as stock as possible.. I would guess that fiberglass and polyester resin would help if you gave it enough layers. Say 6-8+. If you only do 30-40mph then you won't need much additional technology.
mousewheels wrote:Thanks - a good trick to reinforce, and keep a stock looking bike. And your process is instructive.
1989 Elite E with 86cc Dio
Rumia 50mm bore, mini-stroker, 28mm Oko, modified m-x pipe, Carbonfiber reinforced frame.

Image
http://www.youtube.com/watch?v=gKSvdjxvBUA
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bradthreee
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Re: Carbonfiber frame modification

Post by bradthreee »

Just curious as to why not the whole frame?
elitedio
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Re: Carbonfiber frame modification

Post by elitedio »

Hi Bradthree.
Probably wouldn't hurt stiffening the back. In this case I didn't want to take the motor out of the frame. and thought, maybe incorrectly, that with the bigger diameter of the rear section of the frame, it might not flex as much as the 45mm front tube. With the engine out it wouldn't be too hard to add substantial reinforcement there to unitized it.

Too much snow to make it worth dragging out of the basement for a road test but It does seem to be noticeably stiffer in static testing.

I have thought of stiffening the fork stanchions using a similar technique.
1989 Elite E with 86cc Dio
Rumia 50mm bore, mini-stroker, 28mm Oko, modified m-x pipe, Carbonfiber reinforced frame.

Image
http://www.youtube.com/watch?v=gKSvdjxvBUA
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mr pibbs
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Re: Carbonfiber frame modification

Post by mr pibbs »

This has gotten me thinking.

One question: what about your vin?
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Re: Carbonfiber frame modification

Post by aerorob »

elitedio wrote:The frame is cured enough on the secondary layup to remove the fabric. I measured the overall diameter and have .129" of carbon over the main bend and a bit more around the headset area. The back was reinforced with several layers on the rear frame area.
Image
The white spiral lines that you see in the photo are the edges of the heat shrink fabric and have no effect on the structure. Our man in black "Cash" got in this photo.
the weight of that large cat is being supported by your newly reinforced frame, so you must be on the right track :wink:
2001 Elite SR48mm big bore, 90/90, keli vari, yws V8 30mm pipe, 8.4:1 gears 62 mph gps
elitedio
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Re: Carbonfiber frame modification

Post by elitedio »

My vin is on a tab on the footrest bracket. You can see it in one of the photos. Funny place. You would think that the steering neck would be more logical. Guess they are not too worried on a 50.
mr pibbs wrote:This has gotten me thinking.

One question: what about your vin?
1989 Elite E with 86cc Dio
Rumia 50mm bore, mini-stroker, 28mm Oko, modified m-x pipe, Carbonfiber reinforced frame.

Image
http://www.youtube.com/watch?v=gKSvdjxvBUA
elitedio
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Re: Carbonfiber frame modification

Post by elitedio »

Yeah the cat likes to do weight testing but is not much for test rides. He hasn't got the hang of countersteering yet.
aerorob wrote: the weight of that large cat is being supported by your newly reinforced frame, so you must be on the right track :wink:
1989 Elite E with 86cc Dio
Rumia 50mm bore, mini-stroker, 28mm Oko, modified m-x pipe, Carbonfiber reinforced frame.

Image
http://www.youtube.com/watch?v=gKSvdjxvBUA
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bradthreee
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Re: Carbonfiber frame modification

Post by bradthreee »

Great work none the less. And a big "props" to Mrs. elitedio for getting down and dirty :thumbsup:
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