Scooterotica

Having changed the air filter in my pretty standard GP150 I was astounded to find my fuel consumption has just about halved. Which sounds very good. What I don't understand is what it means for the engine?

Initially I was using a standard filter with sharp creased paper. The one I've fitted now appears to be a different material and is not creased but wiggly with not a hint of a fold. I assume this to be an Indian filter and this is the one that is producing the phenomenal fuel consumption. Performance wise I'm not sure there is anything to choose between them. Although, it might be my imagination but it seems a tiny bit more ragged at speed.

My understanding of these things isn't great. So can somebody tell me what is happening? It suggests to me that the Indian filter might be more restrictive and that it is running leaner as a result. Would that be a fair assumption? The plug seems fine. I just don't know what effect this might be having on the engine and need to know what I should be doing about it?

what is your fuel consumption now and what was it before,
might give a clue to what state your set up is in.

As it happens today was a good day to compare the fuel consumption as I travelled the exact same route that I have done previously. Having worked out the mileage on a route planner I was shocked to find it was a little over 43 miles, say 50 for good measure and I needed to fill up. On this occasion it was a round trip of 81 miles and I still hadn't gone on reserve. So actually when you look at it like that it was the previous consumption that was way out and this might be more what you would expect. Still not sure why there should be such a huge difference though. The set up hasn't changed at all. Must have been that rubbish Italian filter I was using.

I recommend you take a look at the colour of your spark plug.
I had to change the main jet on my SX150 when I changed the air filter

Yes, I did. Seemed reasonably healthy. Brown colour, the electrode tending towards being a little light perhaps. The main jet would be my concern as well.