EDIT, I think it's actually a busted pilot jet adjuster.

[-Savage-]

Origionally titled fuel pump woes.

Ok, CBR600FX (carbed) running fine this morning, 40 mile commute. I was running low on petrol, and let her run well into the reserve.
started her after work, and sounded odd, discovered hole in exhaust at the 2 into 1 junction.
Filled her with super premium unleaded or whatever the expensive stuff is called.
Bike is well down on power at low speed, nearly stalling. It is slow to build revs and sounds very "put put put".
Bike seems to be ok at >5k revs.
When I turn the ignition on now, the fuel pump buzzes or clicks, and when I start the bike I can feel a clunk in the pump every second or so. Bike is hard to start.

Any ideas peeps?
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My Bikes - - - Royal Enfield 500 with sidecar, VFR800, CBR600FX,
Peugeot Speedfight 100, Kymco Hipster 125, GSXR750K5, Jawa TS 350

[prawny1]

sound like you've pulled some debris of some kind from the bottom of the tank into the carb, its most likely water and fine rust from the water that gathers in the bottom of the tank, before you start pulling your carbs apart try just draining them then remove the air box lid and with the bike running at a few thousand revs cover the bellmouths with something to make the bike suck all the crap out of the jets(engine can't suck air though the carb mouth so it tries to suck through the carb passaged instead).


with regards your fuel pump it sounds like it is behaving as it should so i wouldn't worry about that, If it was me i would drain the tank and if the fuel isnt to bad decant it into clear bottles so i can see when the water/debris has settled and then carfully pour it back inthe bike along with some water removing additive(can't remember any specific brand but there are quite a few).

[-Savage-]

I had a fiddle about with the relays, a multi-meter and a Haynes book of lies, and it suggests that my fuel transfer relay is faulty.

Anyone have any thoughts?

prawny1 The reason I didn't think it was debris was the 40 mile of fresh fuel it had on the way home. I may try what you suggested though anyway as it would be cheaper and quicker than a new relay if you're correct.
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My Bikes - - - Royal Enfield 500 with sidecar, VFR800, CBR600FX,
Peugeot Speedfight 100, Kymco Hipster 125, GSXR750K5, Jawa TS 350

[prawny1]

What you have to remember is the slow running jets are tiny (fractions of a mm) so once they are clogged usually they wont clear themselves without some form of persuasion.

The fuel pump relay can be bypassed so that the fuel pump runs when the ignition is on instead of being triggered by the cdi pulses, my little honda cb1 has been running like that for a good year and a half (probably 11000 miles or so) with no problems.

[finpos]

Hole in exhaust may be having much more of an effect than you think, it'll muck up the fuelling and you often get fouled plugs.

f.

[-Savage-]

Hmm there is petrol collecting in one of the throttle trumpets, it seems to drip in and pools above the brass disk valve thing.
____________________
My Bikes - - - Royal Enfield 500 with sidecar, VFR800, CBR600FX,
Peugeot Speedfight 100, Kymco Hipster 125, GSXR750K5, Jawa TS 350

[-Savage-]

Ok, now discovered one of the pilot jet adjustment screws is fcuked, looks like it was hit with a hammer.....

Can't get any purchase on it to unscrew it as two of the "castle" tang things have broken off.

Anyone have any ideas? How this could have happened?
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My Bikes - - - Royal Enfield 500 with sidecar, VFR800, CBR600FX,
Peugeot Speedfight 100, Kymco Hipster 125, GSXR750K5, Jawa TS 350

[Pete.]

The thing with that is that unless you actually damaged it yourself it isn't the root cause of your problem, or the bike would not have been running properly before.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[prawny1]

If you have fuel gathering in your carb then your float valve (fuel cut off inside carb) is not closing fully or needs adjustment, which lend credance to the debris theory.

I would get it sorted sooner rather than later because you will be diluting your engine oil with fuel as it seaps past your rings (if the inlet valves happen to be open), and will reduce it's lubrication properties.

[-Savage-]

Checked the jets and seem clear, but I'm going to leave it into the garage tomorrow to get it looked at.

Thanks for all the help folks.
____________________
My Bikes - - - Royal Enfield 500 with sidecar, VFR800, CBR600FX,
Peugeot Speedfight 100, Kymco Hipster 125, GSXR750K5, Jawa TS 350