Gz250 total speed challenge
 

I've heard people say there gz250's can go 75 or more but my stock gz250 only goes about 55 mph pegged out, it really feels like I should have another gear to go into, my question is how many teeth should I go up or down in the back to achieve 75 mph, because as it stands I don't even want to take it on the highway were the speed limit is 55 because everyone travels at 60 atleast, I'm not trying to turn my gz250 into a racer or anything doing any tweak I can , but would love to be able to reach a top speed of 75, so I can go on the highway or even interstate if I wanted, I feel more like I have a moped, only being able to do town riding a back roads were the speed limit isn't over 45, if anyone has a specific way to find this out some kind of calculator or something that would be great , I love my gz250 but it needs to have a faster top speed, thanks for any help

The 16 tooth front sprocket gives a slightly higher top speed in 5th, at the expense of less power uphill. The GZ is not built for consistent speeds over 60-65mph. I would estimate a comfortable cruising speed of 55-60mph. You may be able to get to 75mph downhill with the wind behind you, but I wouldn't recommend thrashing it for extended periods.

I went with the 16 tooth front sprocket on my '09' GZ and have generally been satisfied with the top end speed of 75 on the flat with no headwind. I installed it not to increase my top end speed but to lessen the strain on the engine and thereby increasing it's life span. Each bikes performance will vary a little bit, but you might get a little more out of it by tweaking the carburetor, changing to a different spark plug, etc. Don't expect to get Lamborghini performance out of a Chevy Cruze. Some of the other members will probably come on and give you some additional advice to help out but if you need more speed you might want to upgrade to a different bike.

Check the performance section for tips as well.

Trust me I would love to get another bike as much as I like my gz250 but it would be nice to have something bigger that wouldn't drag when you hit a bump with a heavier passenger or go faster but I got lucky when getting this bike so it might be awhile before I can upgrade, so I'm trying to do all that I can to make it practible as it's our only vehicle, I live on top of a hill but I think it shouldn't lake too much low end from it, the gears could stand to wind out longer anyway,but thank you so much for your guys advice about the teeth I'll probably do that, if I could get 60 mph without having to kill it, then that would be ideal

Ever since I fixed my exaust gasket we're it leaked it seems like it's even harder to get up to speed, feels and sounds like I'm pushing it harder at 45, haven't tried to get to 55 since I fixed it, well I have but to scared to push it any harder, it's got a lot more power and warms up and starts slot better now but I don't understand why it sounds harder on it when trying to get to a previous top speed of 55, I really hope that 16 front tooth helps I've getting it ordered first thing in the morning, thanks again

The exhaust is a key element as to how your bike runs. There has to be a certain amount of back pressure in the exhaust system for the bike to run properly, hence the baffle. Bike owners can attest that when they drill out their baffles or otherwise modify their exhaust system to get that throaty roar they are trying to achieve, the bike runs crappy without changing the orifices in the carb, etc.

Yeah. 55-60 is about where it's at. On mine, anything above that (and there's not much more really) it feels like it's gonna explode.

I've got the 16 tooth up front, and have been contemplating getting a tooth or 2 smaller in the back to lower the rpms a hair..... but really, not sure it's even worth it. These bike aren't meant to rocket around top speed.

I think you have just answered your own question. Not having a lot of power to begin with is a deciding factor when gearing comes into play. I have found the original gearing on most bikes is pretty close for the intended riding purpose.

It is fun to experiment but be sure you want to make the $ investment knowing you may be disappointed with the results.

I've gotten mine to 120KPH. Man you can hear the engine strain at that speed.... twist that throttle!

I'm trying to do all that I can to make it practible as it's our only vehicle, I live on top of a hill but I think it shouldn't lake too much low end from it