Modern Vespa

Hi, has anyone tried water/methanol injection? It's pretty much obvious that it works on larger engines, I'm wondering whether it is possible to implement it on as small as 125 cc? Happy coming Christmas!

I hear that blue meth is more pure.

Sorry. I couldn't help it.

I looked at the title and wondered "what are we up to here??"

I'm looking for cooler burn, I have LX 125 cc, air cooled. Methanol burns cold compared to gasoline, also it's been said it takes away heat while it evaporate within cylinder. Colder brun helps ecology too. Biggest hope is to get rid of engine knock before I fix, it removing its cause. Here is the video on methanol cooling effect and fuel volume compensation principle:

Aahhh ...

It's been said that the mix of 50 x 50 % ofwater and methanol is ideal. More cooling effect and less flamability danger: https://www.motortrend.com/how-to/tested-methanol-injection-on-a-blown-small-block/

I think on Vespa it can be injected just after the airbox. It would be good if the nozzle would do fine mist already. The key moment here is to prevent water condensation from getting into the cylinder, so the inner part of the air duct just before the carb intake should be somewhat "foamy", lined with some porous lining which could collect and hold water droplets. Original radius of air duct shouldn't be changed, of course, so new airduct with modification should be used. Curious if this sounds reasonable? 
I'm thinking this in order to make less abuse to engine, but for those who'd like to modify it further, they could increase compession ratio.

There is water/meth injection kit for carb: Of cause smaller jet for smaller engine woudl be needed.

If it works on larger engines, then probably it will also work on smaller size ones. Working principles and physics are the same, whatever the size of the engine.

What you intend to do is I think unusual. Mostly people that want more power from their 125 simply switch to a 300.

Anyway, interested to learn what you find out in your experimenting.

I have engine knock from engine overheating as I diagnose it. I eventually fix the cause of that, but I thought meth/water injection would be a preventive and cooling measure for long trips.

I see, your basic problem is engine knock. In your ET4 125.

You can inject water vapour and maybe that will solve the engine knock, but it will not solve engine overheating.

You are sure the engine is overheating? It is an air cooled engine. It has a simple cooling system. When the engine is running the fan is spinning and that's it. I am sure you checked the air intake of the fan is free of dirt, and that is all you can do about it. I do not know if your scooter even has a temperature gauge.

Air cooled engines by their cooling system typically do not have a stable engine temperature, and that makes them more sensitive to fuel quality.
Maybe it is the type of gasoline you are running your scooter on that is causing the engine knock.

Thanks for your reply. I have LX with Leader engine that comes from Et 4. I've disassembled the chassis and both engines, so there's no "unclean" places. There was higher than normal oil pressure - soon I will check if that remains the same. I've finished assembly, waiting for the stand pin now. Higher than normal octane fuel would increase time before knock and it would not run after that before it gets cold. On idle it never knocks. Babbit bearing on flywheel side is scored, and crankshaft oil passage most likely was clogged, as I could not push through any oil to the rod bearing. Now it takes some small amounts of it, I didn't find though what oil flow rate should go into the rod bearing. Cooling jet is free of debris and overall, engine inside looks new, it must be because of the engine flush I added to oil before disassembly.

They usually call it nitro, so people are reminded and also not confused.
I did smell some on the road a few days ago. Maybe Veterans Day car cruise, hot rod.
A slightly rich mixture will pop if timed correctly for that hydro boost. Stranger things bro!