Misfiring even in the dry!

My sv650 is 2000 curvy model.

I am well aware of the probs people can have with miss fireing front cylender in the wet weather but mine has started doing it in the dry weather now aswell, even when the roads are bone dry and the sky is clear blue!

I checked my park plus they are spotless (and they were only fitted a month ago when a full service was done!) She is fine until I go on the motorways, sitting at 50mph (local speed limit for the M8 ) but when I slow down and twist the throttle to speed up she starts miss fireing (scares the poop out of me especially at busy junctions!) When this happens I pull into the side of the road and rev her to get her going again and her exhaust pops and farts away a good few times then back to normal again.

My local garage said it could just be the choke getting stuck open a wee bit but she is sitting idleing at just over 1,000.

Truth is I am wanting to get out on the bike again but I am scared as I have had a few nasty scares before. Could it be the choke getting stuck open a wee bit or any one got any other suggestions?

[rictus01]

Indeed, I'd be having the carbs off, check both plungers and the cable, also maybe wise to drain the carbs and see if you perhaps have any contaminates in there ?

Cheers Mark.

[21QUEST]

Yep might be sticking plungers. Air box/carbs sitted correctedly?

If the choke lever to have full travel, easy check for sticking plungers is to grap hold of the metal bits of choke cable at plunger end.
Try gently pulling on them(not so much that they come out of the rubber boots mind).
It should be quite smooth even though spring load and go back in with any hassle when you push it back in. Do that to both ends. A bit of silicon grease sprayed on the metal bits/boot as lubrication (between boot lip)is a good as when doing the above.
With a naked you don't even need to take anything off to do the above.

Also check junction where cable splits hasn't got damaged ie plastic bit of where the front/rear section come out of the jucntion has not snapped off. This would mean the either or both plungers are staying on.


Ben

ps: if going to take carbs of to clean plungers ect, make sure you have an impact driver, correct length/size screw drivers.

It sounds like your having the same problem as I just have. Try checking where the spark plug leads connects to the loom.

It's obviously faulty Tesco fuel. You should immediately book an expensive repair job and claim compensation.

Ok, I gonna suggest carb icing. Always seems to be an issue after continuous speed riding. The weather doesn't have to be that cold, just chilly and damp.

Possible?

Cheers for the suggestions folks. Had my haynes manual out look at how to get into the carbs think I might just leave it to a mechanic, am still on the very basics of fiddling with bike although I understand all the different bits and bobs about them.

Didnt think it was cold enough that day for carb icing but might have been, gonna go for a good run the firs dry day this week, worst should happen I have breakdown cover.

[Biker Biggles]

Have you tried taking out the plugs and seeing if one or both are running weak or rich?If one is running rich it is likely to be that choke plunger sticking,if both are rich it could be the choke cable or a clogged air filter or a carb problem.If one is weak it could be an air leak at that carb intake,and if both are weak it could be air getting in at both carb intakes.Worth a look before spending dosh at the garage.

[fizzwheel]

Choke plungers are easy to get at, I sorted mine out and I'm not a particularly competant mechanic.

i would start with the igntion, check the ht leads, the coils and especially the wires to the coils, one may have vibrated loose leaving it with an intermittant connection, make sure contacts are clean with good electrical connection