Spark Plug Gap

[JohnNorCal]

Ok, I am not a wrench. If I buy the recommended spark plugs for my bikes (K75, 1150rt), do I need to gap the plugs? I remember as a kid watching my dad do it but that was before all of these new designs came out. Thanks in advance.

[T__]

Ok, I am not a wrench. If I buy the recommended spark plugs for my bikes (K75, 1150rt), do I need to gap the plugs? I remember as a kid watching my dad do it but that was before all of these new designs came out. Thanks in advance.

 

John, maybe or maybe not, but you really should.. The plugs will come gapped at the most common gap for that style plug & if that matches BMW specs then it should be correct.. BUT_ even if they were correct to begin with there is always the possibility that the plug was dropped or mishandled in shipment at some point.. SO—yes do at least check the gap before installing..

 

Twisty

[Tipover_Bob]

John:

I had the same dilemma the other day because those dual side electrode plugs didn't lend themselves well to checking the gap and the way they are made it looked like the side electrodes would break off if I tried to adjust them. I kinda checked the gap using a feeler gauge between the center electrode and the side electrodes and the gaps appeared to be right (31 thousands I think), so I left them alone.

 

Tipover Bob

[RFW]

Ok, I am not a wrench. If I buy the recommended spark plugs for my bikes (K75, 1150rt), do I need to gap the plugs? I remember as a kid watching my dad do it but that was before all of these new designs came out. Thanks in advance.

It takes only a couple of minutes to check and (if needed) to adjust the plug gap. Why would you NOT want to do this?

 

The short answer is that if the plug gap is not what BMW has stated, then you need to gap the plug.

 

This issue has nothing to do with "new designs". Some manufacturers (such as Bosch) sell each plug type with several different gaps to cover the needs of different motor manufacturers. When you cross reference your bike in their catalogue, it calls out the version of that plug with the gap that is right for your motor.

 

Other manufacturers may sell a generic plug only that you need to adjust to the needs of your specific motor (according to the bike's instructions).

 

Bottom line is that it makes no sense at all not to AT LEAST check the gap before installation!

[Quinn]

Related question: Do you vary the gap based on how the old plugs look?

[doc47]

As plugs wear the gap increases. Re-gap the plug so it stays within specs.

 

Recommendation: use a wire-loop type plug-gapper rather than a feeler gauge or "wedge" type gapper. The wire-loop is more accurate. (In the real world it probably doesn't matter a lot, but a wire-loop is no more expensive.)

[JohnNorCal]

Thanks for the response. It's not that I don't want to check them, it's just that the new designs, splitfire etc seem that I might do more harm than good.

[T__]

Thanks for the response. It's not that I don't want to check them, it's just that the new designs, splitfire etc seem that I might do more harm than good.

 

John, yes, be very careful if bending on the side electrodes of a dual electrode spark plug as you definitely can damage them.. Put absolutely NO pressure on the center electrode when working with them.. I doubt you will have to move the side electrodes as it is more of a check to be sure they haven’t been tweaked in shipment..

 

Twisty