Top speed on gz250

[Water Warrior 2]

Lynda's GZ hit 80 mph once while on a flat road with no headwind. Windshield and bags on too. This was after figuring in the speedo inaccuracy. Can't for the life of me remember why we were riding that fast. She didn't like it much and never tried again.

[gypsyspit]

I've had my GZ for about a month now. I just got the M on my license Saturday. I just started taking it on the highway in short doses. And to my surprise it actually accells quickly. No mods made to it at all. And vie managed to get a top speed of 75. Haha it's not the safest feeling. But I feel like if I had a straight away and no wind it could push 80. But I'm also 130lbs and don't carry anything on the bike that I can't keep in my pockets

[davesisk]

Hey guys...I've ridden my lady friend's GZ-250 to test it out, and I can only get it up to about 52 - 53 mph in 5th gear. Based on what I read here, it should be able to get up to at least 65-70 or so. (I weight about 170 lbs, so I don't think my weight is the issue.) It's a 1999, and seems to run well, start easily, and generally be in pretty good shape. It does seem to burn just a little bit of oil...maybe 1/4 quart every couple hundred miles. I don't know all the details of the stock exhaust, but there is the one stock opening in the cone-shaped muffler and looks like two additional 1/2" or so holes have been drilled into the back plate of the muffler. (I'm a Suzuki S40 owner, and drilling holes in the back of the S40 stock exhaust is a pretty common mod, so I wouldn't be surprised to find a similarly common mod on the GZ250). So, maybe if the exhaust has been drilled, then adjusting the fuel-air mixture to be a bit more rich would give it a bit more power? Just guessing here (the S40's run lean stock, so adjustment the fuel mixture to a bit richer is another common mod for the S40's...again I wouldn't be surprised if the GZ250 wasn't the same given they are both "thumpers".).

That said, any other ideas on what might be limiting it's top speed so much?

TIA,
Dave

[Jvacustoms]

Have been running the bike too lean probably drilled holes and never adjusted the mixture. Might start by checking the plug it will tell you the mixture. If it is lean as i suspect you might shim the needle and replace the main jet.

Sent from my DROID RAZR using Tapatalk 2

[davesisk]

Originally Posted by Jvacustoms

...Might start by checking the plug it will tell you the mixture...

OK. White plug tip means rich...I don't recall what indicates lean or just right?

Dave

[blaine]

Welcome.White tip means extremely lean,black is rich.light tan is right on the money.You need to increase the size of the MJ & shim the needle.
:cool:

[davesisk]

Ah, OK...so a little more than just adjusting the fuel/air mix then, eh? I assume there's probably some stuff in the How-To section on how to do this...I'll give it a look.

Thanks guys!
Dave

[mrgz250]

I was going to go to a 16 tooth sprocket but think about it take a good look at the
aftermarket ones its a solid piece of steel the factory has a rubber damper in it to lessen
the stress on the chain that rubber is there for one thing only 4me my gz is happy with factory new parts

[raul10141964]

I am 220 lb
my settings
2.5 turns on the pilot
shim needle
140 main jet
16T
top speed 80+
cruse 70-75 (to fast for my taste )
63MPG city

[Water Warrior 2]

Originally Posted by mrgz250

I was going to go to a 16 tooth sprocket but think about it take a good look at the
aftermarket ones its a solid piece of steel the factory has a rubber damper in it to lessen
the stress on the chain that rubber is there for one thing only 4me my gz is happy with factory new parts

The rubber dampner does not lesson stress. It is supposed to lesson the chain noise but I have never noticed a difference.