Random lumpy idle / surging

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

Set off for work this morning, and the bike was idling very oddly indeed - if I tried to set off with low revs it would just stall, but if I give it some, it's fine. As long as I'm riding about 3k it's fine, but anything before then it starts surging.

I left from work today, and the bike was fine, stable idle, perfect. I then set off to my friend's house, after being stuck in traffic and the temperature going up, the bike became lumpy like earlier again.

Not sure what could be causing this. Any ideas?

1998 SRAD 750, fuel injected.
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Current: Yamaha FZ1 '07 | GSXR 750 SRAD

Past: CB125TDC | TZR125 | GPZ500 | CBR600F3 | ZX9-R | GSXR1000 K4

Vincent · Banned Joined: 16 Oct 2006 Karma :

Does the bike have an Fi diagnosis lead?
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P. · Red Rocket Joined: 14 Feb 2008 Karma :

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

No errors.

I am very well versed in bridging the connector... Razz

I wish there was an error so I could diagnose it easier! I'm thinking perhaps a coil on its way out or something.

There is a big dirty connector block with a LOT of pins in it behind the left hand fairing. I took it apart and one was broken, they're quite corroded also. I managed to bridge the broken one and bypass the connector, but the block has seen better days. Any way to clean this sort of thing?
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Current: Yamaha FZ1 '07 | GSXR 750 SRAD

Past: CB125TDC | TZR125 | GPZ500 | CBR600F3 | ZX9-R | GSXR1000 K4

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Coil should give you an error.

When did you last change the air filter and spark plugs?

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

fatjames · World Chat Champion Joined: 09 Jul 2011 Karma :

I had a similar issue, but with my xv535 Embarassed

turned out to be the reg/rec. But that would probably have a fault code too.

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

Hmmm. I really hope it's not the reg/rec. This has been a recurring issue with the bike, but has been fixed by a MOSFET.

Perhaps the connections have come loose. I did only use bullet connectors. Worth a look.
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Current: Yamaha FZ1 '07 | GSXR 750 SRAD

Past: CB125TDC | TZR125 | GPZ500 | CBR600F3 | ZX9-R | GSXR1000 K4

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

I am looking to get a new one, but I don't want to buy one at this time of year - the temptation to ride it will be too great...

What would be a good upgrade from the SRAD? While it has worked I have 100% enjoyed riding it.
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Current: Yamaha FZ1 '07 | GSXR 750 SRAD

Past: CB125TDC | TZR125 | GPZ500 | CBR600F3 | ZX9-R | GSXR1000 K4

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Later model or GSXR1000

K6 GSXR750/1000 Mr. Green

Walloper · Super Spammer Joined: 24 Feb 2005 Karma :

Can I put all my money on a loose connection/broken wire?

The bike is 98? which is a good long time for any weakness in the harness to develop.

It may means a arse-hole of a job with a meter and a continuity lamp spike. Soldering bolt and leccy tape.

I would start at the blatantly obvious such as where the harness runs over the frame etc. Where it is open to knocks or pinching then go on from there.

Don't over look simple battery connections. They can develop high resistance over time which is why they are part of regular maintenance. But you know that I hope.

Could be a simple engine earth connection.

I'm voting for harness as they are often one of the parts replaced when bikes are overhauled (if your's has been overhauled but the original harness re-used). Not a majorly insurmountable job if you have time and a shop/shed/roll-in-patio doors (when she's not in the house Embarassed

).
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W-ireless A-rtificial L-ifeform L-imited to O-bservation P-eacekeeping and E-fficient R-epair

Fisty · Super Spammer Joined: 11 Apr 2007 Karma :

TPS, could need setting and throttle bodies balancing. Gives a lumpy idle and stalling issues.
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TL1000R | Hayabusa | ZXR400 | TL1000S | Bandit 400 V
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Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

Yeah, the wiring on this bike is probably its worst feature. Doesn't help that it has been left outside by me though.

Getting a garage built now so hopefully it should be safe and dry soon! TPS is fine and throttle bodies are fine I should add.
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Current: Yamaha FZ1 '07 | GSXR 750 SRAD

Past: CB125TDC | TZR125 | GPZ500 | CBR600F3 | ZX9-R | GSXR1000 K4

Walloper · Super Spammer Joined: 24 Feb 2005 Karma :

Snorty · World Chat Champion Joined: 13 Oct 2010 Karma :

Well it ran like a sack of shit this morning and on the way home. Tonight it has been smooth as a baby's bum.

Must be electrical.
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Current: Yamaha FZ1 '07 | GSXR 750 SRAD

Past: CB125TDC | TZR125 | GPZ500 | CBR600F3 | ZX9-R | GSXR1000 K4