help!

[AIRWOLF21]

My cbr 125 keeps cutting out when stationary, I've had a new carburetter fitted and the fuel tank cleaned and the fuel tested along with a service and its still doing it. If I keep the revs up when stationary its rideable but does anyone have any ideas?

[sladey1985]

just turn the tick over up till you find out what it is :-)

[AIRWOLF21]

You mean the idle screw? Yeah I suggested that to Simon in gp's but he said as it isnt a fuelling problem it wouldn't make any difference. Glad to see I wasn't the only one to think of that tho, mite just do it anyway to see what difference it makes if at all.

[Day7936]

Was the carb correctly jetted before installation it sound like there's an issue with the idle jet

[AIRWOLF21]

She had the same fault before the new carburetter was fitted, initially Simon just cleaned the old one and we had the same fault so he suggested a new one

[Day7936]

Does ur carb have a throttle position sensor attached to it if so it could be that which would make it a wiring fault as it leads to the cdi just a thought

[AIRWOLF21]

Sadly not, its a 2006 model, no sensors or ecu to fault find

[garyboy]

I read somewhere that ignition faults often seem like petrol faults.
It seems like its not petrol so probably its ignition.
You could start with looking at the plug .. clean or replace .. check gap.
Check high tension circuit .. check connections to coils etc.
then check low tension circuit .. all earth connections, battery etc.

a fouled plug may struggle at low revs?
poor coil will struggle at low revs.
bad earths will lead to lack of current.

[AIRWOLF21]

You aint going to believe what it was! whilst i have no doubt there was a carb issue initially and simon did the right thing in replacing it, he forgot/worked itself loose, the air hose from the carb into the airbox wasn't connected! The circlip was just dangling! I just rode it home now and it was absolutely fine, not being supremely mechanically minded I assume this was the issue, the only thing i cant understand is why did the bike run normally at speed without the airbox connected to the carb?

[blueracer]

Glad you eventually got it sorted 

[garyboy]

see?
I said it was petrol all along !

[walt-n-his 955]

I read somewhere that ignition faults often seem like petrol faults.
It seems like its not petrol so probably its ignition.
You could start with looking at the plug .. clean or replace .. check gap.
Check high tension circuit .. check connections to coils etc.
then check low tension circuit .. all earth connections, battery etc.

a fouled plug may struggle at low revs?
poor coil will struggle at low revs.
bad earths will lead to lack of current.

having a look at my mates zx7r, on the weekend, thats crap on low revs, like its missing, but fine on high revs, you think coil....???

[garyboy]

I only know a few basics.
I read the manual
when the coil went on my Pan, it played up for only a short time, I read the manual and followed the elec/ignition tests, and founf a reading on the multumeter that was not to spec .. new coil too expensive so got a secondhand one off internet search, .. rreplaced.. fine!
if it was the coil I think you would soon know, as it is very apparent, not going at all on low revs.

petrol/ignition faults are very difficult to diagnose, esp for an amatuer like me, sometimes u swear that its electrical but it could be mixture, or timing.
wot I do is check over the easy basics .. connections, plugs, wires .. (or tubes, jets, filters ..) if not find .. then follow manual guidance check for items .. it can take a long time and may be easier (and cheaper) to pay an expert

[walt-n-his 955]

I only know a few basics.
I read the manual
when the coil went on my Pan, it played up for only a short time, I read the manual and followed the elec/ignition tests, and founf a reading on the multumeter that was not to spec .. new coil too expensive so got a secondhand one off internet search, .. rreplaced.. fine!
if it was the coil I think you would soon know, as it is very apparent, not going at all on low revs.

petrol/ignition faults are very difficult to diagnose, esp for an amatuer like me, sometimes u swear that its electrical but it could be mixture, or timing.
wot I do is check over the easy basics .. connections, plugs, wires .. (or tubes, jets, filters ..) if not find .. then follow manual guidance check for items .. it can take a long time and may be easier (and cheaper) to pay an expert

cheers mate, thanks for that, looks like he's got me working all weekend then.. , never mind , he can bring the tinnies..

[Lunkhead]

It's a mixture thing. The engine has to have the correct proportion of air to petrol - by not having the airbox the engine is having too much air (or too little petrol depending on how you look at it). When you remove the airbox/filter to make it go faster, you have to re-jet the carb to make it run right again.

I used to have a twin with a crap coil, a brand new plug would let it run fine for a couple of days. If I swapped the coils it would run fine on the other cylinder. Give this a go (if it has more than one coil, don't know about ZX7Rs). I had another bike with the reverse problem (no guts at high revs) and it turned out to be a split in the diaphagm in the carb allowing too much air at high revs and destroying the vacuum.

I learned a long time ago to give a job to a professional first as last, esp with tuning stuff..