ride to work this morning was sweet til i got a few miles to work. all of a sudden massive pop noise out the exhaust like back pressure? then running as if it on 3 cylinders like a gargling noise wen rev???? like a loss of power.

managed to limp back to cusins shop. vacume pipe was split so replaced that... still no change...

poss spark plug?
if not what can it be need this bike to get to work so urgent response please!!!!! help

Get a multimeter and check your battery's voltage.
Had a similar problem like this to my old 250.
Large Pop sound with a huge black smoke out of the exhaust, then revs start dropping.
Cam

Is it running on 3? were you revving it much? Is it making knocking ot clacking and clattering noises?

you can check all the plugs with a 13mm socket but doubt it is that - plugs either work or they don't.

If it is making nasty noises I'd be wary of riding it as it will probably get worse....

not too helpful, sorry..but difficult when you are 100 miles away!

RIGHT UPDATE!!!

right replaced both rear spark plugs .... not that.

replaced both ht leads on the back.....not that.

vacume pipe was split replaced... not that

tested fueling ...not that.

tested front ht leads..... not that

back right hand side cylinder isnt firing as run bike for a little.....spray gt85 of the exhaust pipe out of cylinder head n evaporates but back right doesnt.

all ht leads n spark plugs spark good.

going to try some CDI units tomoro??????? any other ideas or views?

CDI affects 4 cylinders, coil 2, and if all sparks are good, then look elsewhere.

Is it flooding, sounds like No 3 was not firing, then it did and ignited unburnt fuel.
check compression
Common to No3 cylinder.

vacuum hose
carb
plug
cap
lead
piston assembly and valves
The fitting/sealing of the above.

I agree with Arsey, not likely to be CDI. Does the bike make any unusual noise when its running? or turning over?
Long shot but; do you have a compression tester?
can you take the rear cam cover off and check the valves are all behaving as they should?

valve clearences wer done about 5 months ago.

n yeh it kinda sounds like a vtwin lol or long shot if u have ever heard a hyosung gtr125 lmao as a mate had one and now sounds very similar haha

and im sorry to say i dont own a compression tester plus i dont no wat one looks like haha

well i would check that you haven't fecked a valve if it sounds like a Hyosung then it may be sick

But it had a valve clearances not long ago,And it wasn't ticking its head off before it went

Have you over revved it? I blew a valve in my 35 by over revving. same sort of symptoms had a pop then loss of power.
If you can get the cam cover off C1 and C3 you can turn the engine manually and check for correct operation of the valve train.