That is not necessary on a 2stroke. You are either running lean (more air than fuel) or you have a old 2stroke with a bad combustion chamber design. detonation or pinging does not cause that amount of excessive heat, but running to lean does cause detonation and extreme heat. Enough heat to melt aluminium. here is a good read on the subject http://www.thumpertalk.com/topic/456014-2-stroke-terms/
Also no 2 of the second post on that link I posted above^^ is not correct when concerning a 2stroke. That ignition advance explanation used apply's to 4T. A 2T ignition curve looks like this
Just come to America and buy pump gas let it sit in a plasitc gas can for a while you will have H2O and ethenol free
You are going to have to find a different pump, because those windscreen washers cannot hold pressure. You need to find a pump with a high enough pressure capability to atomize the mix. But for now you can use the system you mentioned and later if you want to improve it you can do so. Also if you don't have methanol you can use just water. Battery power wont be to much of a problem those small battery packs used in those fast rc cars would probably last two days. The most difficult part would be to make a automatic switch of sorts. What bike is it?
Seems like your water injection project is a solution in search of a problem. I'd start off with the basics, fix the jetting and timing to get rid of the detonation. Then maybe look at a new/modified radiator setup to remove more heat from the head.
If you have a very highly tuned race motor, which detonates due to very high compression, then if you can get methanol no problem, then why dont you run the bike on 50/50 methanol/petrol mix? This will mean no more detonation, and should provide a bit more power at the same time.
I would suggest that if you cant get the fuel required to run your race motor successfully, that it might be a good idea to sell it and replace with something less highly tuned, which will run on pump fuel? Not sure on methanol being illegal for race use though.............nitro methane is much nastier and is used in race applications all round the world!
Sad to say, I think you on the wrong track. The symptoms you describe are typical of (a) too much ignition advance and (b) a compression ratio too high for the ignition you're running. As someone else posted, you have solutions looking for a problem. Forget the methanol and water, and go back to basics for ignition timing and ignition system type. I'd also look carefully at whether your porting, head, and piston set-up make sense. (FWIW, I've built TZ 250, 350, 700/750 Yamaha engines to produce - consistently - far more than the power the factory ever got out of them. None of the factories were stupid; it takes a lot of science to do better than they did.)
Ignition. All your changes (and the fuel) mean that a factory ignition curve will be totally irrelevant.
I would say that even with a digital ignition with 3D mapping possible, that other changes made to this motor will mean its only ever going to work at very high rpm, and may well need alcohol fuel.