I have an intermitant fire on my ST4 916 I have changed plugs, HT leads, coli & fuel injector. Will run great for 5 miles then start to misfire sometimes the front cylinder but mainly the rear. Any ideas?? Many thanks
More detail required i think. What speeds and conditions when this occurs. Does it sit happily at idle ?
Two quick checks - make sure the big multi-pin plug on the side of the ECU is secure. And check the big multi-pin plug to the left of the headstock - if any damp gets in there it can cause corroded pins which lead to all sorts of weird thing happening. Just a thought - is there any contamination inside the fuel tank? The fault my not necessarily be electrical...
Many thanks for the replies. It happens intermitantly, usualy get 5 to 10 miles before it starts playing up but have had 40+ miles to work but the fault happened in 5 miles coming home in the cool evening. Can happen at any speed. I can leave it to cool down for up to an hour and it sometimes restarts and sometimes does not.
Good point, MC. Have you plugged a plug to see how it looks? If it is misfiring I'd imagine you'd have sooty/blackened plugs from fuel burning when it isn't supposed to. If not, then it might be a fuel delivery issue, as pointed out, possibly filter or crud related. A
