Mileage and Speed
 

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 ???

Yep, there is definitely something different.

It doesn't need to be big. Parts made by different subcontractors with somewhat different tolerances and different combinations of these parts might do it. Tiny differences in carburetor could make large differences in gas mileage.

There's a similiar mistery here in Spain. Talking about stock bikes, they run from 50 mpg to 80 mpg. Sometimes it's caused for the riding style, but in other cases there's no explanation. They're mounted in Spain, but some pieces -like the engine- come from Japan.

Depending on which bike, they ride from 72 mph to 86 mph; for the top speed, and from 60-65 mph to 75-80 mph; for the cruising speed. Such big diferences for the same model. :??:

I can't figure it out. I get the same mileage as always but, as you mentioned, can't break 60MPH at full throttle and I'm a lightweight. My buddy can shoot 80 with a 15T sprocket and he's a middle/heavy weight.

That being said, I get better mileage than he does.

I would guess that it has to do factory jetting and location. However, with the two bikes I am familiar with, they were purchased at the same store 2 months apart and we live in the same town. I don't know if they came from the same facotry.

I can't figure it out. I get the same mileage as always but, as you mentioned, can't break 60MPH at full throttle and I'm a lightweight. My buddy can shoot 80 with a 15T sprocket and he's a middle/heavy weight.

That being said, I get better mileage than he does.

I would guess that it has to do factory jetting and location. However, with the two bikes I am familiar with, they were purchased at the same store 2 months apart and we live in the same town. I don't know if they came from the same facotry.

Went riding with my wife today. 148 miles her mileage 75mpg mine 58.

Amazing. And since you were both travelling together, you must have done close to the same as far as stopping and starting goes. That's really quite a difference, too - about 25% or so.

You were wondering how long these chains last before they need to be replaced, and now I'm wondering where I'll get another 16T sprocket to put on with the new chain. Does anyone know if Suzuki makes them or has them or ???? I would sure hate to go back to 15T.

Yikes. You HAD to bring that up didn't you!
Actually it is good that you did; I hadn't even thought about it.
I saved my original 15T just incase.

I'm a little reluctant to even say this 'cause somebody is bound to mis-interpret, twist, take out of context or otherwise mangle it but here goes anyway:

If you keep a close eye on chain wear and change it before it is really worn out, you might be able to keep the same sprockets through more than one chain. Depending upon conditions, the chain usually wears more and sooner than the sprockets. It is best to change them together as a set but if you watch things closely, it may not be totally necessary.

I have no proof of this (as usual - I guess a lot), but I'll bet some of this is exactly the same as the JT sprocket:

http://www.harris-performance.com/websi ... atalogBody

Seems to me that most 16T sprockets made for a 525 chain would work. Anyone have any thoughts?

If the "hole" in the middle is the same.
That part is kinda important too! :tup: