miss fire or not

[spongeyrockster]

Hi All
I own 2004 Rockster with 51000miles on the clock
I have a running issue that doesnt matter if its a hot or cold engine.
If the weathers hot or cold,
how long the engine has been running.
It doesnt matter what rev's or speed, it might just affect the effect (stalls when cold)

For example : riding along at 30mph, steady rev's, intermitantly, almost like one stroke doesn't fire. If cold it may well stall when rolling upto junctions.
It also does it at faster speeds but because of the momentum it has a smaller effect.
Dont know if it would be electrical or mechanical.

It has been dealer serviced and I asked them to check for a miss fire. They informed me it wasn't a miss fire but potentially a repair of £400 per cylinder head

I dont know how to eliminate electrical from mechanical
Can anybody help to find the problem? dont mind paying for the help.


Thank you
Simon

 

[Steptoe]

Hi All
I own 2004 Rockster with 51000miles on the clock
I have a running issue that doesnt matter if its a hot or cold engine.
If the weathers hot or cold,
how long the engine has been running.
It doesnt matter what rev's or speed, it might just affect the effect (stalls when cold)

For example : riding along at 30mph, steady rev's, intermitantly, almost like one stroke doesn't fire. If cold it may well stall when rolling upto junctions.
It also does it at faster speeds but because of the momentum it has a smaller effect.
Dont know if it would be electrical or mechanical.

It has been dealer serviced and I asked them to check for a miss fire. They informed me it wasn't a miss fire but potentially a repair of £400 per cylinder head

I dont know how to eliminate electrical from mechanical
Can anybody help to find the problem? dont mind paying for the help.


Thank you
Simon

It sounds very much to me like the VERY COMMON problem of your main spark plug coil caps - about £90 each from Bmw and 30 seconds work to change requiring no mechanical skill or specialist tools. Easy to test , just search for coil, plenty of threads on the subject.

 

[Steptoe]

While i eat crumpets and have a cup of tea waiting for the engine to cool down on todays job i'll take pity on you having to wade through the results of searching for "coils" and post how to test the main coil caps/stick coils.

Unplug the lower the lower secondary spark plug caps from the spark plugs, then see if the bike starts on just the main plugs.
If they are the problem the bike may not start at all or it may only run on one side.