98 gsx600f

[rperry03]

+1 ^^ if you were going that fast and still had rpm left I check the front and rear sprocket unless you know for sure and what is the rear tire size?
I've had a stock pre 600 with an indicated speed of 145mph for a few miles, but my gps only recorded 130 something and it was around 9500rpm-ish.

And the dyno to know for sure if stock or not

[92xjunker]

I was riding with a friend he's got a newer Speedo that was recently recalibrated cuz of new rim and tire setup so I know I was within a few mph of what mine said. Even so I was going at least 130 and still had about 4500 more rpms to go

Speed vs RPM is based off gearing. A stock Kat will redline at 130 give or take. I would suspect the gearing was changed.

[Kreylyn]

Put it on a dyno, that will tell you if the output is more than stock rated with out having to tear into it.

Until you post something like that, most everyone here is gonna continue to think your speed measurement was off. Every stock bike speedo is, usually by 10% or more.

Krey

[99turbokit]

I was riding with a friend he's got a newer Speedo that was recently recalibrated cuz of new rim and tire setup so I know I was within a few mph of what mine said. Even so I was going at least 130 and still had about 4500 more rpms to go

[shpielers]

Verify the speed with a GPS, the speedo is off by ~10%.its probably stock.

[99turbokit]

Just got my first bike about 2 months ago need help!
I've done some research and my bike stock is supposed top out at 130. Guy I got it off of didn't know if any motor work had been done or not. I've personally hit 140 and still had more to go. That being said I wanna know what's been upgraded on the bike already, like gsxr cam swap or head work but don't know how to tell what's been done. I am a mechanic but never worked on motorcycles before besides the basic stuff I've done to my bike now, and want to do some uprgades but wanna know whats already been done first. Any help or advice would be greatly appreciated!