Wednesday 4 January 2017

Reinforced bashplate

The XRV 650 is a very protective piece of alluminium: It covers the whole engine and even both side very well.

But between the bashplate and the engine there is an air gap, this means that in case of a big it, the bashplate can deform or break and the engine can take diretly an hard hit.
This doesn't happen on trial motorbikes, because between the skid plate and the engine there is a hard rubber.

Rubber between skid plate and engine on a Gas GAs TXT.

This could be a solution for spreading the force of an impact, the best improvement for the XRV 650 bash plate, but the rubber has to be shaped with the shape of the engine, this is a difficult operation without removing the engine. Moreover the shape of the skid plate itself it is not studied for taking big hits with hard object (i.e.: Hitting a rock or holding the whole weight of bike and pilot).

So I decided to not follow this solution.

Some producers as Boano or Africaqueens have different skid plates, they are not very expensive (200-400 €), and have some improvements (Boano sells a skid plate with pouches on the side for olding tools & general stuff).
These solutions are anyway out of my budget.

A good improvement of the skid plate, is to make it stiffer by increasing the alluminium thickness or by adding some composite material, as fiberglass or carbon-kevlar.

I decided to follow this solution because it is very easy and can be cheap.
With less than 35 € you can buy fiberglass and resin. There are two type of fiberglass, with an ordered mesh fibers or without mesh. The first one costs more but it offers more tensile strength (Along fibers), the second one is cheaper and has less tensile strenght as the fibers are shorter.

I've used the fiberglass without mesh as it is cheaper and there are no mechanical requirements for my application (layer of mesh kevlar would have been nice for improving the resistace to impacts, but I think the one of the fiberglass will be enough...big hits will show results!)

Easy work, clean the bashplate, pass some rough 60 sand paper on the lower part and on the low sides and inside if you are planning to close the oil drain hole. Then cut pieces fiberglass as big as possible in order to match the surface of the skid plate, in order to make 2 or 3 layers.
Then...just follow a tutorial on how to make composite fiberglass.
Easy peasy.
When the composite was completely dry, I've put 8 rivets on the bash plate, in order to ensure that the fiberglass will always be connected to the alluminium bashplate...in case the resin will detach from the alluminium.

At the end I've passed some epoxy plaster on the border in order to make them look smother.

 The reinforced bash plate.

Detail of the closed oil drain hole, filled with stucco for making it look smoother.


UPDATE 25.05.2017

I've been riding the XRV on offroad for a couple of kilometers, from some easy gravel roads to some very hard and muddy muletracks on the Linea Cadorna, a WWI defensive trenchs system in Italy on the border with Switzerland. The bashplate took some its, so at the oil/filter change, I had to remove it and I could see that it is in perfect shape. The fiberglass is sticking perfectly to the alluminium.


2 comments:

  1. You risk anodic corrosion between the steel rivets and the aluminum. Check those frequently, or change them with aluminum rivets.

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    1. You are completely right and I didn't think about this. But actually the rivets are completely useless as the fiberglass sticks very well to the alluminium (I had no idea about this, so I placed them just in case).
      Next I will removed them and leave the holes open so that any liquid/mud can flow out of the bashplate more easily.

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