Sunday, 4 July 2010

CCM tracker up-date

After much umm'ing and ahh'ing, I've decided on a Seeley Commando Mk3 hump from Ragged', for my on-going CCM tracker conversion - I basically don't want an XR750 look-a-likey body kit. It's going to need some customizing to mate nicely with my Sprite tank. Chunky arse with rounded tank combination sounds all wrong, but I figure it works suprisingly well on the Seeley, so why not suck it and see? BP.A Seeley Commando earlier today.
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6 comments:

  1. Nick5 July 2010 at 07:44

    Check with Spike, there has been a lot of trouble with fibreglass tanks and the Ethanol thats now added to fuels, Gary Jenkins (part of Benzina) has personal experience of this as seen on his small Ducati on the Moto Piston rally at Somo, in Spain. the fuel was delaminating (big bubbles on the surface), a lot of short circuit racers have changed to Alloy tanks and the price of fibreglass tanks has dropped on ebay. Petseal is also braking down and creating a honey like goo in carbs. It doesseem to be okay if you don't leave the fuel in for too long i.e. drain the fuel out after each event

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  2. Spike5 July 2010 at 08:27

    tis true... I am looking at obtaining some Hetron998 resin or similar so that my tanks will be OK. I am awaiting response from suppliers regarding price and suitable gel-coats and bonding pastes...
    Probably wont be cheap though.
    If you are using ethanol in a polyester tank, or a tank that has been petsealed, I would advise draining the tank after each race if possible and always storing with the filler open so that excess fuel can evaporate.

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  3. Spike5 July 2010 at 08:29

    HERE'S THE TECHNICAL BIT;
    Polyester resins, gel coats and fillers commonly incorporate phthalates. In even the best resins and layups a small proportions of these phthalates remain unreacted. There are several water-soluble molecules that are found in these materials and they play a central role in blister formation and delamination. Phthalates are only sparingly soluble in water, however many are readily dissolved by ethanol.

    Whereas gasoline free from ethanol never picks up phthalates, when ethanol was introduced the very small ethanol molecules diffused into the fiberglass, filler and gel coat materials where they dissolved unreacted phthalates. Having been dissolved by smaller molecules, and almost certainly accelerated by osmotic pressure, some portion diffused back to the surface and was dispersed in the gasoline. Based on our GCMS results to date there are some other, presently unidentified, large molecules that were also leached out by the ethanol and similarly transferred into the gasoline.

    This internal solution and diffusion back to the surface is the process of leaching.

    Since they are in solution, the phthalates and the other heavy dissolved molecules are able to pass through the fuel line filters. When the gasoline with ethanol evaporates in the carburetor the heavy molecules do not evaporate but come out of solution and are carried along in the air-fuel mix as an aerosol. When the droplets impinge on throttle plates and on the walls of the induction system they can collect as reported by Chuck Fort at BoatU.S. We do not presently know if after impingement the films are immobile or if they are able to migrate through the induction system towards the intake valves. Some of the molecules that impinge on the hot valve stems and under the crowns decompose to leave carbon powder and ash. Others, such as the phthalates that in general have exceptional high temperature stability, remain intact or undergo only partial decomposition and then act as the binder that holds together the carbon particles and ash as the observed, black sludge.

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  4. Nick5 July 2010 at 09:45

    Spike, thanks for that,

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  5. Anthony Brown5 July 2010 at 11:38

    The chemistry is beyond me but..

    I have been using this product to seal my Glass tanks for the last couple of years no problem with any fuel so far seems to be really good as long as its properly cured. I have left fuel in the tank constantly

    http://www.tankcareproducts.co.uk/index.htm

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  6. Spike5 July 2010 at 14:13

    Excellent!
    That may prove cheaper than using specialist resins..... May make my life easier too, I have tried a couple of chemical/fire resistant resins and they have been horrible to work with [as if working with GRP isn't bad enough ;) ]

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