Low rev misfire

[f-4]

My 04 plate MZ1000S has recently developed an irritating misfire below 3,500 rpm - above that it's fine. Low speed running is lumpy and occasionally the engine cuts out completely. I first thought it might be dodgy fuel, but it's gone on for too long - I have checked the air filter and changed the spark plugs to no avail. I've read of possible coil issues elsewhere, but otherwise a bit stumped - anyone else had the same thing?

Oh, and it's Friday 13th, so the gear linkage decided to undo itself 50 miles from home - bodge job to get home!

[DAVID THOMPSON]

i have had a lot of problems with loose spade lugs in the wiring harness
the little curl on the lug just seems to loose its grip on the spade
both the traveller and the rt125 have done it
also had them just break off the end of the wires

also some night start it up in the dark in a place thats very dark
and see if you get a light show from one or all of those coils and plugs
i have an old bmw with a homemade ignition box and some times
when its very damp and humid i get a big light show from the plugs and caps

i never did like the coil on the plug idea
the coil on a bike takes a lot of abuse

also a bad load of gas i have had lots of problems with bad gas
for several years here where i live i run 90 octane no ethanol in the rt125
it refuses to run if i try the other
dave
2002 rt125 97 traveller bmw 71 r75/5

[den]

have you tested for air leaks ,? , I would test it this way.
At low revs when your experiencing the misfire,Spray around the inlet manifold with "easy start".If there is a leak then the revs will go high because of the suction of the easy start fumes?

have you changed your plugs,, sometimes a crack in the ceramic can cause this,

[MJ310]

I have had the same problem a few years ago an traced it to a coil, changed it and all was sorted. Unless you modify a car one to fit or change them for Triumph coils (along with the connectors) I think the aprillia ones are the cheapest. I modifies a car one and it works perfectly.

[f-4]

Thanks all for the replies - it seems coils are dodgy on older bikes, so that may be the first step after checking all the connectors. Will keep you posted!

[boilermaker]

F-4
There is a massive amount of info on this forum concerning the coil on plug system fitted to your machine. You will also find info on the Benelli/Aprilia/Triumph/Ducati websites as these useless components are fitted to a number of different makes of machine and they all have the same problems.