PICO-PICO wrote:If the possible risk with gasohol is=
issues with rubber fuel system components, and to machines that already have some corrosion in fuel tanks, because the alcohol will probably clean up the metal surfaces, so leaving the corrosion to travel around the fuel system and engine.
1. The question is = what is defined as OLDER BIKES ??
2. Is the potential monetary loss
a) the entire engine or
b) or cost of partial overhauling ???
[/b]
I said 'older 'bikes, because I am not sure when manufacturers started using rubber seals and hoses that were compatible with the alcohol in gasohol. Probably more than 5 or even 10 years old, but thats a guess. The problem is more likely to be found in bikes with carburettors because they have more rubber components, but as the good captain has found out the Phantom is not having problems and Honda have made sure that it is OK with gasohol. It is easy to specify the correct rubber o rings, seals and gaskets which are resistant to the benzine alcohol mix which is gasohol. It is also possible to change 'older' non resistant, o rings and seals with resistant ones. Not to big a job I would have thought, but I have no idea if they are readily available in Thailand.
Very difficult to quantify the risks, I have limited personal experience with 'older bikes' here in Thailand so I speak from a knowledge of rubber compounding and solvent attack and just common sense.
The whole engine could not be affected because only the Petrol tank, the pipes to the fuel injection or carburettors, the inlet to the cylinders come into contact with unburnt gasohol. I have never heard of problems with cylinder bores, pistons or valves, or the exhaust system. The whole of the bottom part of the engine and gearbox has no contact with the fuel, and so cannot be affected.
The petrol tank corrosion issue is not caused by gasohol, it is caused by the high and variable humidity climate in Thailand and by some 'older' bikes spending a long time with little fuel in the tank, while not being used, the parts above the fuel level are the most liable to corrosion. At some point the corrosion will cause problems wether gasohol is used or not, but if its there it is possible that using gasohol will cause the some of the corroded metal to separate from the tank wall and enter the fuel system.
I have probably not been too much help here, but I think Pico's desire to be able to calculate the possible cost of repair of gasohol damage, and see if less than the saving in purchase price, is just too difficult to quantify.