Hey guys!
My name is Alex, I'm 30 years old and living in Austria. Until now, I've joined the German forum from the moment I purchased my '04 FS 650.
It's been nearly 5 years now and as time goes by, I've faced a few issues with the bike yet, but I could handle them myself with a little help of the forum and my autologous skills.
But since last year, the bike has been making trouble concerning idling and misfiring in every rev range.
I had a carb rebuild (FCR 41 MX) with all new jetting and needles, also every gasket replaced!... no major changes at first.
I've also replaced the whole ignition system (regulator, stator, CDI, coil, spark plug, cable) due to a electrical short, caused by a disintegrated flywheel. Symptoms were no charging of the battery and misfires respectively stalling when closing or opening throttle or even at mid to high revs...
Having that done, the bike was running perfectly again...smoth throttle response, rock-solid idling, excellent starting behavior (nearly no choke needed at all), no choking even when ripping the throttle from zero to full in an instant.
But as I said, since last year, the bike behaves somehow strange again. After winter, I took her out for the first ride...just 3 kicks needed to get her going. Strangely, when letting of throttle, the engine - not always - didn't immediately rev down to idle speed....staying a little elevated for a few seconds, but then stable.
At first, I was thinking of a jammed throttle cable somewhere, but that could be sorted out...
Next step was to get the carb out again and clean it, also checking for abnormalities...but also nothing to be found. I've also checked the throttle slider and put some gasket paper in to get the distance to the carb housing to a proper one again... no significant changes.
So I went on, searching for another ignition package, thinking my battery (a LiFePo) could have damaged the whole system due to an electrical short or by extremely discharging it while starting the bike by e-start...but not this time, everything remained the same after changing CDI and stator again.
The bike starts quite easily, but can just hold idle speed with the choke pulled...without, it stalls immediately. If choke is engaged and throttle is opened, the misfiring starts, one can also see too rich fuel mixture by smoke coming out of the exhaust at that time.
So furthermore I disassembled the valve cover to check for valve spring failure, which wasn't the case, either....
An engine specialist suspected some crank shaft- or corned bearing failure as a possible cause... but for my, that would explain the idle problem (higher resistance while turning, so more fuel needed), but not the misfire issues...
I'm kind of baffled right now, because nothing I've tried before has led me to any improvement so far...
So maybe one of you guys here has got a handy hint for me?
Thanks in advance!
Alex
My name is Alex, I'm 30 years old and living in Austria. Until now, I've joined the German forum from the moment I purchased my '04 FS 650.
It's been nearly 5 years now and as time goes by, I've faced a few issues with the bike yet, but I could handle them myself with a little help of the forum and my autologous skills.
But since last year, the bike has been making trouble concerning idling and misfiring in every rev range.
I had a carb rebuild (FCR 41 MX) with all new jetting and needles, also every gasket replaced!... no major changes at first.
I've also replaced the whole ignition system (regulator, stator, CDI, coil, spark plug, cable) due to a electrical short, caused by a disintegrated flywheel. Symptoms were no charging of the battery and misfires respectively stalling when closing or opening throttle or even at mid to high revs...
Having that done, the bike was running perfectly again...smoth throttle response, rock-solid idling, excellent starting behavior (nearly no choke needed at all), no choking even when ripping the throttle from zero to full in an instant.
But as I said, since last year, the bike behaves somehow strange again. After winter, I took her out for the first ride...just 3 kicks needed to get her going. Strangely, when letting of throttle, the engine - not always - didn't immediately rev down to idle speed....staying a little elevated for a few seconds, but then stable.
At first, I was thinking of a jammed throttle cable somewhere, but that could be sorted out...
Next step was to get the carb out again and clean it, also checking for abnormalities...but also nothing to be found. I've also checked the throttle slider and put some gasket paper in to get the distance to the carb housing to a proper one again... no significant changes.
So I went on, searching for another ignition package, thinking my battery (a LiFePo) could have damaged the whole system due to an electrical short or by extremely discharging it while starting the bike by e-start...but not this time, everything remained the same after changing CDI and stator again.
The bike starts quite easily, but can just hold idle speed with the choke pulled...without, it stalls immediately. If choke is engaged and throttle is opened, the misfiring starts, one can also see too rich fuel mixture by smoke coming out of the exhaust at that time.
So furthermore I disassembled the valve cover to check for valve spring failure, which wasn't the case, either....
An engine specialist suspected some crank shaft- or corned bearing failure as a possible cause... but for my, that would explain the idle problem (higher resistance while turning, so more fuel needed), but not the misfire issues...
I'm kind of baffled right now, because nothing I've tried before has led me to any improvement so far...
So maybe one of you guys here has got a handy hint for me?
Thanks in advance!
Alex
