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Canuckinatruck · June 1st, 2023, 02:27 PM

Hey all,

I have a 2003 ZZR250 that I picked up cheap for a starter bike. After having my uncle do the carbs and valves, then doing brake lines, new rubber and making an MT09 fender fit, it's finally ready. Right? Right?!?!?! After a few shakedown rides and a celebratory rip when I got my plate on, I was pretty sure it was.

Wrong. I took it to work yesterday, normally 30 mins on mostly 80kmh roads. So I got about half way there after it started and ran fine. Out of nowhere, in 6th gear at 7500rpm, it started surging, like I was hitting the back brake then releasing it. After a few surges, it started slowly losing power. I tried to drop a gear and the revs wouldn't come up, they just faded down to 0.

Stopped on the side of the road, I tried to refire it. Turned over but won't start. Choked it, still no start. Checked fuel, still lots and it's not old. Finally it fired up again after a few minutes. Continue down the road for a few minutes and it happens again. And again. And a 4th time 200 feet from the gates at work.

After work, same thing. Starts fine, rides fine for 10 minutes or so, then surge and die. It became more and more frequent on the way home, dying every minute or two.

Everything seems visibly fine. One spark plug was tan and dry, the other was more black but dry. Wiring to the coils and plugs all looks good. No whoosh from the gas cap. Switching fuel tap to prime to bypass the vacuum didn't change anything. Fired it up today to move it to my barn, ran fine.

Anyone know where to start here? I was super stoked to finally be legal to ride and now I'm debating burning the bike to the ground.

June 1st, 2023, 02:27 PM	#1
Canuckinatruck ninjette.org newbie Name: J.J. Location: Niagara, Ontario Join Date: Apr 2023 Motorcycle(s): 2003 ZZR250 Posts: 9	Surging then Losing Power Hey all, I have a 2003 ZZR250 that I picked up cheap for a starter bike. After having my uncle do the carbs and valves, then doing brake lines, new rubber and making an MT09 fender fit, it's finally ready. Right? Right?!?!?! After a few shakedown rides and a celebratory rip when I got my plate on, I was pretty sure it was. Wrong. I took it to work yesterday, normally 30 mins on mostly 80kmh roads. So I got about half way there after it started and ran fine. Out of nowhere, in 6th gear at 7500rpm, it started surging, like I was hitting the back brake then releasing it. After a few surges, it started slowly losing power. I tried to drop a gear and the revs wouldn't come up, they just faded down to 0. Stopped on the side of the road, I tried to refire it. Turned over but won't start. Choked it, still no start. Checked fuel, still lots and it's not old. Finally it fired up again after a few minutes. Continue down the road for a few minutes and it happens again. And again. And a 4th time 200 feet from the gates at work. After work, same thing. Starts fine, rides fine for 10 minutes or so, then surge and die. It became more and more frequent on the way home, dying every minute or two. Everything seems visibly fine. One spark plug was tan and dry, the other was more black but dry. Wiring to the coils and plugs all looks good. No whoosh from the gas cap. Switching fuel tap to prime to bypass the vacuum didn't change anything. Fired it up today to move it to my barn, ran fine. Anyone know where to start here? I was super stoked to finally be legal to ride and now I'm debating burning the bike to the ground.