Misfire ?

[pdh]

OK, I'm new to the group. Posting in electrics becasue I 'think' it's a spark issue. But what do I know!! Feel free to move it if wrong.

2002 bike with 6k miles on it. Been stood for a year. Fuel was drained (but could have been a small amount in the bottom of the tank). Was running fine when stored. Filled with new fresh fuel but very lumpy tick over. I thought a ride out would help, but it didn't. Lots of backfiring under acceleration. Power will come and go under fixed throttle. Seems better under light throttle but struggles if you open the throttle at all while moving. By the time I got back from about 10 miles it would hardly run. Dies as soon as clutch it disengaged and then struggles to restart - lots of backfiring and popping. Starts just about at zero throttle and you can sometimes coax it into life and higher revs if you are careful on the throttle. Revs pick up but virtually no power. With all the popping and backfiring I'm guessing it's getting fuel that is not being burnt into the exhaust. So I'm guesing some sort of spark problem. Feel free to tell me I'm completley wrong. Bike has not been used enough to ever need any work done on it other than oil and filters etc. so it's in 'as new' set up - no mods etc. Stored in a 'dry' location (log cabin in my garden) but may have seen some damp over the winter, as I'm in the UK. Never needed a wash, becasue it's never been in the rain. That makes me sound like a wus, but I do also ride a Z1000sx every day, including the winter.
Any advice much appreciated.

[Snapey]

Beautiful bike. I'll guarantee it's not spark but a blocked fuel filter.

[pdh]

Happy to look at that - is it in the tank or outside it?

[Mick_J]

I'd say fuel pump or clogged injectors.  Pump is easy to check first, whip it out of the tank and get it stripped (Breaks down to 4 bits, body, fixing bracket, pressure relief valve and retaining clip)
The tea bag filter clips to the bottom of the fixing bracket, then give a good shooing with carb cleaner, remember to wire the pressure relief valve onto the body when done.

[KiwiCol]

In the tank.   I'd agree with Snapey, blocked tea bag filter or perhaps an issue with the fuel pump itself. Do a flow test on it before you take the tank off n just see, worth a go to see how it is anyway.

[pdh]

Thanks everyone - will give that a try over the weekend.

[grog]

Mate,also think fuel prob. Maybe the high pressure still had fuel in it, wouldve turned to glug after a year. Just a thought.

[Hooli]

Another vote for fuel filters here too.

A guide to most of the job is here - https://gsx1400owners.org/forum/index.php?topic=6232.0

The big black high pressure filter can some times be back washed with carb cleaner or something to blow the crap out, I don't think Seth's thread covers that.

Sounds like you don't have the workshop manual, you can download that here - https://gsx1400owners.org/forum/index.php?action=downloads;cat=6 it's in two parts I believe. You'll find the figures for the flow test in there etc.

[grog]

High pressure filter a PIA. Snapey will agree on fix.

[pdh]

OK, so good call everyone - teabag was a mess and lots of crap in the bottom of the pump casing.





I've put a new teabag filter on and it's now much happier. However still hesitates on hard throttle, so I think I maybe didn't get enough carb cleaner in the HP filter, or maybe the injectors need a clean. Would that be the next step?

[grog]

pdh, i know i go on about it but fitting external filter just makes a different bike or pay the bucks and replace internal. Cleaning internal works for some, my opinion is its still reducing fuel flow. External been on mine quite a few years now, never a problem, easy mod, costs 50 bucks max. Just makes a free revving motor.

[pdh]

That's interesting. I can see taking the teabag off is easy, but how do you bypass the HP filter? What external filter would I use?
Paul.

[Hooli]

There's a guide on here.

https://gsx1400owners.org/forum/index.php?topic=590.0

[pdh]

So an update. I took the injectors out and put them in an ultrasonic bath with some carb cleaner. Lots of crap came out. Then I put the fuel pump including the built in filter in the ultrasonic bath. Loads of crap came out of that as well to the point of turning the carb cleaner brown. Refitted the injectors. Refitted the pump and ran it (just turning ignition on and off) to pump fuel into a container, not into the nice clean injectors - it was brown fuel for about a litre then started to clear. Another litre and it was nice and clean. Refitted the pipe working and fired it up. Still a bit flat on revving it. Took it for a ride and still not picking up cleanly. Then it got a lot worse - very lumpy.

Let it all cool down and fired it up again. No 1 exhaust was stone cold so no combustion on one. Checked the injector resistance and it was same as all the others. Pulled the plug and it was pretty black so fitted a new one. Instantly better. Changed all the other plugs as well. Bike now running sweet, pulls cleanly from tickover to red line.

So I think that the fuel issue was a problem but it was combined with dirty/failing plugs. Fixing both those issues has got the bike back to 'as new' running.

Thanks to everyone who offered advice. It was really appreciated and got me on the right track to fixing the issue.