Misfiring? 1100s please read help req

[mincer]

Hi Guys any help or advise would be grateful.
Ok bike spec 1100s 99 v plate ,34 thou miles VDL exhaust and chip , brisk plugs , lennies air scoop and k&n , oils etc in order recent change, .went out for a tootle sunday after 5 miles out and bike begins to miss , opened her up to see if this would clear it , no cigar got worse to a point were the bike was loosing power / cutting out and popping more than the usual vdl exhaust noise . Got her home.no warning lights.
Tank off , plugs out look ok , plenty of fresh fuel no loose wires or anything to say what the issue is.
Answers on a postcard , going to have a trawl thru issues posted previous but if anyone has had this issue mail me .
Thanks in advance
Dave

[Blackal]

One stick-coil breaking down?

Was it old fuel before topping up with fresh?

Still misfiring on new fuel?

[mincer]

Hi ,
No the "old" fuel was fairly fresh went to cadwell the other week and was running ok then.
As for coil other than having a specific test not sure got a feeling it is ignition side before pulling things off and replacing eh oh.
Mines a 99 model so the coils are under the tank

[mincer]

just been reading other posts re rough running /misfiring , going to check the fuel tank re poss water ? and clean the injectors as required ,of course any comments welcome

[nab 301]

Difficult to diagnose but If you're going to check for water in the tank , change the fuel filter while you're there . After that it's really just methodical checking . Do a quick visual check for the small rubber blanking plugs under the throttle bodies on the vacuum take offs. ( one might be missing) Also the rubber inlet manifolds cracked badly on my bike a few years ago so I replaced them although bike was fine at the time) After that check the resistance of the plug leads just to be sure , if original they're nearly 20 yrs old , also it seems to happen more on GS's but make sure one of the throttle cable outers isn't unseated , if you open and close the throttle with the engine off you'll hear if the throttles are hitting the stop screws at different times when closing .
After all that I'd be doing a compression check/ check valve clearances just for peace of mind. I'd change plugs after all that just to see ?
After all that I think someone on here had a fuel pressure regulator problem ( sticking open I think?)

[mincer]

Thanks for the info , on with filter at present and will check those you have mentioned.

[Jeff Highland]

While you are in the tank, check the U-tube for splits and tight fit on the barbs. Mine had deteriorated so it was loose (only showed when wet, tightened up when it dried)

[ted]

its easy to dismiss the simpler things. Start your diagnosis from a solid base - replace the plugs with brand new ones otherwise you can do lots of work when the plugs are at fault.

[mincer]

Hi ,
thanks for your replies , so checked pipework etc all ok, plugs good, spark good , fuel filter changed always a faff job but its done now , cleaned residue out of tank all ok , injectors cleaned and checked ok ,fresh fuel ,back together and taken for a shakedown without the bodywork on .
Started noted tickover too low , ran ok but started to fluff on part throttle between 2-3 thou it was noticeable , but not misfiring ,baulking as previous , took a look at you tube poss requiring idling set up ? to solve issue so I don't have the gauges so a trip to the dealer or anyone know a good ind mechanic in North Lincs .
Thanks Again for your input.
Dave

[nab 301]

I can't help with a local mechanic but joking aside if you've no vacuum gauges you can make a manometer with some clear tubing , oil, and a piece of timber . To speed up the idle you can open the large brass air screw on each throttle body an equal amount as a temporary measure.
If you do decide to balance the throttle bodies yourself, it's best to check the valve clearances first, as these can have a bearing on the balance.


DSCF07922 by Nigel Burgess, on Flickr

[fizzerian]

sounds like a hall sensor issue