Mileage and Speed

[Gadzooks Mike]

I used to think that folks who said they got 85mpg on a regular basis needed new calculators, and those who said they regularly travelled at 85mph we using metric miles or something. However, I'm thinking that there are two or three distinctly different GZ250 bikes and we haven't picked up on that yet. Here's a couple of examples:

I rode with a group not too long ago, and three of the group rode GZ's Two of them the same model year and color but one got 65mpg and the other got somewhere around 85mpg, both travelling together at the same speeds. Another person here owns two and the two get very different miles per gallon.

The next case is a person who has a GZ and put a 16 tooth front sprocket and can no longer get his bike moving faster than about 60 mph, while I can get mine up to 65-70mph on level ground with a 16 tooth sprocket. His friend can run 75 or so with a 15 tooth front sprocket.

I'm not sure if other mods have been made here with some of these, specifically the needle mod to rich up the mix a bit. However, it seems as if the differences are BIG and seem to just happen at random.

So, let's hear it. Anyone have any ideas or anything about this? Are these things being made at two different factories or something? Different parts? Different ???