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BEC cutting out

littleman - 9/6/10 at 07:11 AM

Long story short i have purchased a BEC which has a running problem. It ran fine before it ran out of fuel on the test drive but now struggles to start and will not idle on its own, once it is started it will run for a few minutes max and then lose power and come to a complete stop. It was sitting for a while before being taken on the test drive.

Am i right in thinking that this is probably just a case of needing to clean the carbs out?

Hellfire - 9/6/10 at 07:20 AM

Before we can give you a proper informed answer, we need to know what you have, all we know so far is that its a BEC.

More details would be handy... type of engine, where it came from. Those sorts of details

Steve

r1_pete - 9/6/10 at 07:23 AM

I'd clean the entire fuel system out and replace all the filters, unleaded goes of pretty quickly and as it evapourates in the various components it leaves its sludge behind, causing blockages and th epoor running you describe.

If you just clean the carbs, bore crap will be washed off earlier parts in the system and gloop them up again.

littleman - 9/6/10 at 07:35 AM

quote:
Originally posted by Hellfire
Before we can give you a proper informed answer, we need to know what you have, all we know so far is that its a BEC.

More details would be handy... type of engine, where it came from. Those sorts of details

Steve

Sorry mate, its a ZX9r 'e version' engine, not sure where it came from, but there is a receipt for it somewhere.

[Edited on 9/6/10 by littleman]

littleman - 9/6/10 at 07:41 AM

quote:
Originally posted by r1_pete
I'd clean the entire fuel system out and replace all the filters, unleaded goes of pretty quickly and as it evapourates in the various components it leaves its sludge behind, causing blockages and th epoor running you describe.

If you just clean the carbs, bore crap will be washed off earlier parts in the system and gloop them up again.

Thats just what i want to hear mate, hopefully its only that! When you say the entire fuel system do you mean: Tank, lines, pump and carbs? And filters do you mean jsut the fuel filter?

Also what would be the best way to clean these parts out? Is there a particular brand of cleaner you would recommend?

Sorry for my ignorance but i'm a bit of a newbie when it comes to bike engines and carbs!

Bluemoon - 9/6/10 at 08:02 AM

I think the running out of fuel might be a clue? Maybe you just have some air in the fuel line?? Or you drew some rubish into the first fuel filter when the fuel was low??

Some people find a lot of swarf (aluminum left over from drilling holes in the tank etc) in the fuel filter as they were not cleaned out enough before fitting the tank...

Dan

mangogrooveworkshop - 9/6/10 at 08:39 AM

Took mine for its mot and its running like a bag of nails. It has stood for a while so its just goo in the carbs. Coming back it ran fine and by the time we got home its purring like a pussy cat

Get some carb cleaner and get the varnish cleaned out.
Running out of fuel may have drawn the crap out of the tank and is restricting the flow of fuel.
Clean the pump out and filter as well.

[Edited on 9-6-10 by mangogrooveworkshop]

[Edited on 9-6-10 by mangogrooveworkshop]

MK9R - 9/6/10 at 08:52 AM

Can you hear the fuel pump priming when you turn the ignition on, and does it keep clicking every few seconds as it keeps the pressure?

matt_gsxr - 9/6/10 at 09:01 AM

Agreed, when you run out of fuel with those carbed pumps they run superfast. The fuel in the system normally helps cool them and slows them down.

The pump could be unhappy as a consequence. Replace the fuel filters and see what flow rate of fuel you are getting through.

Hopefully you won't have to remove the carbs and clean them out, as that is tough to do.

Matt

MK9R - 9/6/10 at 09:07 AM

while you are at it, fit a glass filter just before the carbs, its really useful as you can see if the fuel flowing/priming, and any crap in the system. Also where is the pump, near the tank or in engine bay, the pumps push better than suck

matt_gsxr - 9/6/10 at 09:23 AM

Actually I have read this again.

It ran out of fuel on the test drive, and stopped working properly, and you still bought it.

I hope you got a bargain.

MK9R - 9/6/10 at 09:49 AM

quote:
Originally posted by matt_gsxr
Actually I have read this again.

It ran out of fuel on the test drive, and stopped working properly, and you still bought it.

I hope you got a bargain.

are you sure it ran out of fuel and it wasn't this problem??

littleman - 9/6/10 at 09:57 AM

quote:
Originally posted by MK9R
Can you hear the fuel pump priming when you turn the ignition on, and does it keep clicking every few seconds as it keeps the pressure?

Yes i can hear both of these happening.

quote:
Originally posted by matt_gsxr
Actually I have read this again.

It ran out of fuel on the test drive, and stopped working properly, and you still bought it.

I hope you got a bargain.

Dont worry mate i did get a bargain, depending on the time/money it costs me to fix that is. Its worth the gamble!

quote:
Originally posted by MK9R
are you sure it ran out of fuel and it wasn't this problem??

Yeah i am pretty sure that it ran out of fuel as it was working fine for 20-30 mins of the test drive. Then it worked ok for about a mile after topping up the fuel. The guy was decent though, not the type of guy who would knowingly sell a dodgy motor!

BenB - 9/6/10 at 10:11 AM

I'd suspect goo in the carbs.... You could always make up a relatively concentrated Redex mixture and run the engine on that to clear things out if you want to try and avoid taking apart the carbs to clean them....

But first I'd probably try swapping the fuel pump. It's always good having spare parts and they don't last forever so even if you prove it's not that it's not a biggy....

Major Stare - 10/6/10 at 06:53 AM

Id take the fuel line off before the carbs and start the pump to see if its pumping.
If the fuel is dirty, then pump the tank out.
Replace pump if required/not pumping correctly.
Replace any fuel filters and fit a new one before the carbs.
Check for perrished fuel pipes and replace if required.
Check fuel electrical system for loose connections.
Remove carbs and clean fuel system.

tony-devon - 10/6/10 at 08:37 AM

just strip and check the carbs, its easy and false economy to chuck redex etc through there, strip, clean and know that its done properly

probably an idle jet blocked with varnish that had occured during the parked up time

leve it parked, it might drop out and back to the bottom of the bowl, until the next time you use it

badding - 11/6/10 at 07:00 AM

Hi.

I'm driving a zx9r mk indy, and I had the problem that it was difficult to start..
Carbs were clean..fuel pump rattled...

I took the fuel pump of the car, but couldn't find any problems with it, but i decided to swap it. I looked for a replacement pump but was afraid I bought a pump with the same issues.

So I swapped it with this one...
http://locostbuilders.co.uk/forum/35/viewthread.php?tid=137208

Car starts now ok..no probs anymore.

littleman - 11/6/10 at 09:20 AM

Is there much involved in removing the carbs to clean them? I think i'd rather remove them and clean the whole thing out just to make sure it isnt going to happen again!

tony-devon - 11/6/10 at 09:35 AM

nope they are easy,

where abouts are you in the country?

littleman - 11/6/10 at 10:49 AM

quote:
Originally posted by tony-devon
nope they are easy,

where abouts are you in the country?

Thats alright then as i have no experience of anything with carbs. Is it literally just a case of taking them out, cleaning them and putting them back in? No specialist skills required?
I'm in Newcastle, about as far away as you can get!

andrew.carwithen - 12/6/10 at 08:00 AM

Take them off as a complete asembly (drain float bowls then undo the four clamps holding them on the inlet stubs and remove fuel hose, throttle and choke cable -if fitted) - DON'T then strip them down into individual carbs.
Invert the complete bank of carbs and remove each float bowl (3 or 4 screws per carb)
Any varnishing will be apparent as its a golden colour.
Just concentrate on one carb at a time so you can use the others as a reference for re-assembly and remove the floats, float needle valve, main and idle jets. Soak these in carb cleaner and using a soft toothbrush, clean the float bowl and carb body with carb cleaner to remove any 'varnishing'
If you have access to an airline/compressor, use compressed air to dry the carbs and blow through jets - don't be tempted to use thin wire to poke out any blockage which may be present in them as you could scratch the bores and ultimately upset the fuelling.
Re-assemble the carb and check floats are free to move and that float valve lifts accordingly before re-fitting floatbowls.
Now turn carbs right-way-up and then remove plastic carb tops to expose rubber diaphragm. Lift diaphragm c/w main needle and throttle slide. Check diaphragm for splits and that spring and needle valve is seated correctly and not bent etc.
Repeat on othe carbs and re-assemble.
Re-fit carbs, prime fuel pump and see if starts - checking that fuel is not pumping out overflows etc.
carbs will need balancing/synchronising to ensure smooth running and clean pick-up.
Just had a thought - have carbs been dyno-jetted? (larger mains and different taper needles etc.)
Check no. stamped on main jets when removed and compare to standard spec.

silky16v - 15/6/10 at 02:28 PM

if in ay doubt about the cleaning of the carbs take them to a motorbike specialist and have them stripped and cleaned

don't what ever you do spray carb cleaner on the rubber diaphragm as they are very thin and can cause them to wrinkle

i've had the same problems on my old ZX9 BEC and removed the fuel tank flushed it with petrol and then used an air line to dry the inside and removed any dirt replaced the inline fuel filter flushed all fuel lines stripped and cleaned the carbs re-assembled, balanced the carbs at idle and it was a different car to drive, it felt like it had gained a bucket load of low down power

littleman - 16/6/10 at 09:12 PM

quote:
Originally posted by andrew.carwithen
Just had a thought - have carbs been dyno-jetted? (larger mains and different taper needles etc.)

Yes mate they have been dyno jetted, does this make a difference to my problems?

littleman - 22/6/10 at 06:59 AM

UPDATE:
Got the car home and started tinkering on, took the carbs off, the float bowls were clean as a whistle so i unblocked the jets and refitted the carbs. Runs a little better, i had it idling for a while once i had adjusted the fuel pressure regulator but its misfiring a lot. Dirty spark plugs?