NGK plug caps

[Tony Roche 17]

Hi everyone 

My trusty steed has become less trusty recently! It falters intermittently but I can now make it happen regularly if I pin the throttle from about 2000 rpm. I've taken the plug caps off and one of them looks dodgy like it's been arcing on top of the plug. They're NGK LD05 EMEK. I'd like to buy new ones as a first step but can't find them anywhere online. Lots of people are selling the LD05f but they're for threaded plug tops. Has anyone replaced them before or does anyone know where I can get new ones? Thanks guys

Tony

[Andy m 23,609]

I'd buy from a Honda dealer. Fowlers have stock of NC700 ones

 

Plug caps are top three for pirated badly parts, complete with faked logos on mouldings and packaging. Not worth trying anything else IMHO. If you are on a budget someone scrapping a bike is a better bet than Chinese dross claiming to be new. 

 

Andy

[fj_stuart 4,760]

Spark plug caps £100 a pop when NGK caps are about £4 each! Do they do something special that I'm missing?

[Tony Roche 17]

Thanks for your messages guys. I'm with you Andy on buying genuine Honda in general but also that is an eye watering price! I do get a 20% discount from my local dealer as I use them alot so will give them a call tomorrow. Incidentally I've just put a multimeter across both of mine one is reading 5.14kOhm the dodgy one 4.64kOhm. That feels like enough of a difference to me to explain what's happening. What do you think?

[Andy m 23,609]

58 minutes ago, fj_stuart said:

Spark plug caps £100 a pop when NGK caps are about £4 each! Do they do something special that I'm missing?

Certainty they are correct and an organisation that will take them back if they aren't. 

 

The difference in resistance would convince me to change them. Can't you swap left to right and prove the error goes with the camp? 

 

Andy

Edited May 31, 2021 by Andy m

[kayz1 2,928]

You could buy a Corsa Stick coil for less...do you think they may fit..have seen it done before on a bike..no idea if the water proofing would be to standard thou.

Edited May 31, 2021 by kayz1

[fj_stuart 4,760]

1 hour ago, Tony Roche said:

I've just put a multimeter across both of mine one is reading 5.14kOhm the dodgy one 4.64kOhm.

 

The difference doesn't seem significant to me. Also the dodgy cap has LESS resistance - how would that affect running? As Andy says swapping the caps would be worthwhile.

[Graham 3,177]

1 hour ago, fj_stuart said:

Spark plug caps £100 a pop when NGK caps are about £4 each! Do they do something special that I'm missing?

...pairs nicely with those $60 spark plugs!

 

[Tony Roche 17]

Thanks again for your messages guys. I don't know how the plug caps are constructed but it looks like there's been some arcing inside the dodgy cap. I'm suspecting some electrical leakage internally so not all the current is getting where it needs to. I'd attach some photos but not sure how to/if I can. Cheers

[Tony Roche 17]

Here's the dodgy one!

[Tony Roche 17]

 

[fj_stuart 4,760]

It looks like you could get in there with a bit of Emery paper or a Dremel & wire brush to clean it up. Also I'm a fan of Halfords electrical contact cleaner that seems to fix most things of this nature.

[Steve Case 957]

These are not spark plug caps, they are COP.

 

2017 Corsa 1.4 COP on Eurocarparts £104.

[Steve Case 957]

Sorry I take it back they're not COP, just looked at the picture.

 

Looks like Honda wanted to fit COP then chickened out and fitted coils and custom spark plug caps...

[Steve Case 957]

Hold on, why have Honda fitted 2 coils. Surely cheaper to fit one and run a wasted spark...

[fred_jb 10,269]

Probably something to do with the uneven firing interval which I believe is 270 degrees.  The wasted spark trick presumably only works for symmetrical arrangements.

[Steve Case 957]

oh yeah , that would make sense

[Tony Roche 17]

Hi guys just thought I'd update the post. The second hand coils with caps arrived in nice condition. Swapped the plug caps......no difference. Swapped the l/h coil and all is well again :-)

I suspect it was the HT lead as there's a tiny split in it. Thanks for your messages guys. Cheers Tony

[Rocker66 34,488]

28 minutes ago, Tony Roche said:

Hi guys just thought I'd update the post. The second hand coils with caps arrived in nice condition. Swapped the plug caps......no difference. Swapped the l/h coil and all is well again 🙂

I suspect it was the HT lead as there's a tiny split in it. Thanks for your messages guys. Cheers Tony

Glad that all is well again.

[Slowboy 20,560]

Thanks for responding, that might help someone else another day.