CBR impossible problem?

[BikerMatt]

Hello all, absolutely baffled.. for the past 2 weeks I have been working around the clock trying to fix this, so.

My cbr125 all of a sudden had developed a stalling/cutting out problem as if it's being drowned with fuel whenever you go past 1/4 - 1/2 throttle UNDER LOAD.. the bike was running like a gem before and still does AT IDLE and will redline with ease AT IDLE. The bike is regularly maintained, from my work so far i have ruled it down to electrical

So far I have done:
major OCD carb disassembles and cleans
changed spark plugs, coils, caps and wire leading to cap itself
replaced entire wiring loom+tried 3 cdi's
replaced top end+gaskets
new ignition
3 tanks of different fuel+redex
tank cap (because of vent)
fuel line and breather+no kinks
air filter
battery is HEALTHY
it is earthing fine
pick ups are spot on+timing
disconnected clutch+side stand switch
no splits or leaks @ intake

edit: plug is wet+strong, constant blue spark and black in colour
compression is NORMAL
choke functioning normal
all fuses fine

dunno what else i have done on the top of my head, any help greatly appreciated, thanks
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So many bikes..

[FriendlyEllis]

From
https://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp?mode=nml

"Dark coloring, such as heavy black wet or dry deposits can indicate an overly-rich condition, too cold a heat range spark plug, a possible vacuum leak, low compression, overly retarded timing or too large a plug gap.

If the deposits are wet, it can be an indication of a breached head gasket, poor oil control from ring or valvetrain problems or an extremely rich condition - depending on the nature of the liquid present at the firing tip."
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Honda CB600F Hornet 2013 -> Kawasaki Z1000SX ABS Tourer 2015

[RodYork]

does it have a choke?- could that be stuck in the ON position at the plunger?

[bugeye_bob]

Pick a 2nd hand carb up for what they cost,
see if the problem is the same,
Sounds like a carb issue if its over fuelling

[BikerMatt]

Thanks for the replies, will try to get another carb on it and I've ridden with the choke fully on before and didn't make much of a difference apart from exhaust popping
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So many bikes..

[RodYork]

[BikerMatt]

Ok I think I understated a little bit but the choke and carb is functioning fine, does it's normal job but it looks like the problem's pointing towards the pickups so will do a diagnostic on Friday
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So many bikes..

[Pete.]

Vacuum tap? If so, set it to prime and block the vac hose to make sure that high engine vacuum isn't pulling fuel past the diaphragm.
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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

[BikerMatt]

[Jonny491]

Take the top of the air filter off and take out the actual air filter and see if its full of petrol. If it is check the little black hook thing and the float as that might need replacing as its constantly flooding it. Thats what happened to my cbr anyway, one day it was working spot on took it the shops then it stopped.
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Honda cbr 125 2006- Sold, Current 2012 yamaha XJ6N

[BikerMatt]

[davebike]

Sounds to be fuel air mix
If not standard air filter /exhaust it has been re jetted yes ??
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Dave
NC750Xdct + others at work !
davebike1@gmail.com

[clancy]

[BikerMatt]

Yeah would like to stay on topic thanks this is about my bikes bogging problem not my bike mods and what you think of it. Yes it has been rejetted with an exhaust and has been fine for a year and never missed a beat, just this sudden problem has come about
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So many bikes..

[clancy]

[BikerMatt]

[Clutchy]

Do you still have the original air filter?

If you're bored, put it back on and see if that makes a difference?
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Malaguti F12 Phantom-Dead, Suzuki AY50- Dead, NRG power DD LQ, CBR125.
*33 BHP restriction up on 10/12/14* Current bikes/car: SV 650 S/ MKIV GOLF
Guide to pass your test with no lessons!

[bikenut]

many years ago.........bike starts and runs great but when its ridden it wont pull the skin off a rice pudding...........on stand everything seems great, but when riding the problems starts.....that's what he said..........so i see it and its as described, and when ridden the problem started....that is till it stood up whilst riding.............a rag under the seat blocking the air intake when sitting on the seat!!

it happens dudes......a long shot I know but stuff like this happens......
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nuts about bikes

[BikerMatt]

Clutchy- still have it, was going to try that after testing the vacuum

bikenut-.... hahaha
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So many bikes..

[bikenut]

true story dude........
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nuts about bikes

[bikenut]

does the front bit of the exhaust glow red hot?? does the ign advance properly as you thinks its electrical..........use a neon plug cap and "see" whats happening with the ht.........does it stop flashing or goes intermittent??

revs fine on the stand but goes flat when riding..........
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nuts about bikes

[BikerMatt]

[BikerMatt]

Hmmm made a massive leap in progress I'd say.. disconnected the vacuum and it runs like and absolute dream until it stalls when you come to a stop. I have taken off the tap and sprayed it along with the pipes and installed it back onto the tank TIGHT (bit loose before ) and put some sealant around the thread, wait for it to dry and see the result.. there was also petrol creeping out the thread before like how water runs down the side of a glass if you pour

edit: tested it and it's back to bogging but taking the vacuum off makes a noticeable difference
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So many bikes..

[BikerMatt]

Nailed it, the vacuum has been leaking the whole time
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So many bikes..