Bike running like a bag of shit

[1990nc30]

hi ppl,
As above, the bike now and again is running shit. I've had the problem for a while now but have finally decided to post it up on here to see if you guys have any ideas of what could be causing it. I went to open the bike up today on the way home and after 6k onwards it just coughs and splutters all the way up the revs with little blips of power then crap again, i think it feels like it's running on 2 or 3 cylinders or something!? It's really anoying me now coz most of the time it will be running sweet and i'll be well happy and then the next time i go out it will be crap! As i say it's fine when i'm cruizing at 60mph, taking it up to 6k, but as soon as i open it up it's a nightmare!
I think i will take the plugs out at the weekend and check gaps and check the air filter. I had this problem before and after seeing a little puddle of oil under the air filter i changed the filter and it seemed to have sorted the problem, but i can't imagine it's that again as i haven't had the new filter on that long.
If anybody has any ideas that would be great coz i really wanna get it sorted now.
Cheers guys!

[CMSMJ1]

you got to start with the obvious.

plugs will be fine - they normally either work or they don't. none of this intermittent surging kind of issue.

Sounds like you have either got dirty carbs and they need a clean out or some form of elecrical earthing issue - now and again you get no go...

mechanical stuff i normally broekn until fixed....and gets worse if not fixed..

electrical stuff can be a real git and disappear for weeks on on end.

For this one, my 20p is on some form of elec issue - poorly charged battery, poor earthing..that kind of thing. Speed restrictor issues - loose connection dropping it to 2 cyl now and again..that kind of random stuff!

oil under the filter will be from your breather hopefully - you sure you have it topped up right? on a level surface?

[1990nc30]

Thanks for the reply cmsmj1, yeh the oil is fine I topped it up the other day under the maximum line. I think you might be right about it being an electrical issue as when I put my full beam on for country roads at night it goes groggy just like the problem I’m having now, as soon as I turn the full beam off it flys again!???

[Neosophist]

Check the earths.

The usual suspect is at the front by the airbox

[wullvfr]

intemittent problems are usually electrical issues,like everyone says start with the obvious......earths etc.


william

[1990nc30]

Thanks guys, I will check earths over the weekend!

[Psychosomatic88]

I used to have a similarish sounding problem on my VFR, GSXR and also the RGV. I used to find that the VFRs rev would climb a few thou rpm then back fire and almost retard back down the revsand bounce about. Found it to be damp around the HT's etc and used to play havoc on all said bikes. The VFR woulkd loose the front cylinders when in nasty wet and be a little bit gay after being still damp.

GSXR 400 = w8nk in the wet, loosing both outer cylinders very easily. RGV never had many cylinders to loose so was very noticable i.e no go at all .

Not saying it is this, but is worth WD40 around the plug caps and leads etc for the sake of it. It is cold and nasty this time of the year, making a good preventative. :D

[nath30]

my bike did that for a while i changed the m-max box with a spare seemed to sort it out

[1990nc30]

Hi, I've now found that when it's doing this if i turn the headlights off, it runs fine. So left headlights off and on the way to work this morning it was running poorly below 6k revs so i had to thrash it down the motorway to get anywere, i thought that this may have been due to carb icing or something. But on my way home (it was dark so i had to use lights) it was running crap yet again so every opertunity i had i turned the lights off and low and behold it sprung into life again, then lights on and started running poorly again.
So, my problem seems to sort itself out when i turn the lights off. I think it might be the reg/rec or the alternator. Can anyone give me any ideas for what it could be according to these symptoms?!
Any ideas and advice would be greatly appreciated!
Thanks alot!

[CMSMJ1]

You are going to be finding a knackered generator is my bet.

Mine was melted and I could ride to work in dalyight but riding hme was a nightmare race to get back before the battery went flat... the more revs you gave it the better it worked. I guess yours is the same

Get a multimeter and check the charging across the battery at 5k revs. Should be over 14 volts at least. 13 won't do...

If that is OK...then unplug the generator wire by your right knee - white block with yellow wires. Do a resistance check across the 3 pins in the generator side. should not be any resistance - chk haynes on that as I might be lying..lol

Deffo right to look at electrical charge issues. I used to run 3 batteries and swap one every morning...I even had one at work for a while..lol