Spark Plug Issues

Tips, tricks, questions and answers to tech questions
Falcoholic
Posts: 37
Joined: Fri Mar 20, 2020 5:33 pm
Has thanked: 46 times
Been thanked: 16 times

Spark Plug Issues

Post by Falcoholic »

Well I found the culprit of a serious misfire on my Caponord eventually. 1200 v twin with 2 plugs per cylinder. The last plug to be pulled from the fron cylinder revealed this. I've never seen a plug go like this before. My worry was that the ceramic insulator was still inside the bore so I bodged up a hose from the vacuum cleaner and gave it a good sucking out I managed to get it all put back together again with a new set of plugs, cleaned air filter and cleaned up the sensors in the exhaust and reflashed the map using TuneECU. It runs amazing. Had it out for a quick 40 mile shake down last night and all is sweet. So I suppose my question is, what would cause this? The other plug looked exactly as it should do. Image
User avatar
Skub
Posts: 12176
Joined: Mon Mar 16, 2020 5:32 pm
Location: Norn Iron
Has thanked: 9836 times
Been thanked: 10149 times

Re: Spark Plug Issues

Post by Skub »

Probably just a faulty spark plug.

If it happens again,then it may not be the sparker. :lol:
"Be kind to past versions of yourself that didn't know what you know now."
Walt Whitman
https://soundcloud.com/skub1955
JackyJoll
Posts: 3740
Joined: Sun May 03, 2020 10:11 pm
Has thanked: 261 times
Been thanked: 1266 times

Re: Spark Plug Issues

Post by JackyJoll »

I’ve seen detonation break up the ceramic.
User avatar
KungFooBob
Posts: 14223
Joined: Sat Mar 14, 2020 1:04 pm
Location: The content of this post is not AI generated.
Has thanked: 539 times
Been thanked: 7539 times

Re: Spark Plug Issues

Post by KungFooBob »

Yeah, knock/detonation can damage the ceramic insulator, but I'm with Skub, probably a dodgy plug.

I didn't know the Capo had a twin spark head.

The Italians love a twin spark head, I was once told when I asked about Alfa T-Spark engine that it was because the wops couldn't design a combustion camber for shit!
Falcoholic
Posts: 37
Joined: Fri Mar 20, 2020 5:33 pm
Has thanked: 46 times
Been thanked: 16 times

Re: Spark Plug Issues

Post by Falcoholic »

Skub wrote: Mon Jun 01, 2020 6:36 pm Probably just a faulty spark plug.

If it happens again,then it may not be the sparker. :lol:
This is my my fingers crossed option based purely on the basis that the other plug in the same cylinder is ok. I am reliably informed that the two plugs fire independently i.e. the lower one fires a micro nano second after the top one to complete the burn, so if there was an issue with detonation would it not affect both plugs?
Would any issue of detonation be managed by the ecu to ensure correct timing or could there possibly be a mechanical timing issue that the ecu wont alter?

Am I being unjustly paranoid?

I was out for a wee run again last night and it runs great :crazy:
Le_Fromage_Grande
Posts: 11236
Joined: Mon Mar 16, 2020 6:40 pm
Location: The road of many manky motorcycles
Has thanked: 607 times
Been thanked: 4124 times

Re: Spark Plug Issues

Post by Le_Fromage_Grande »

Seriously lean mixture could cause that, but it would have effected both plugs and you'd have a hole in a piston.
The two plugs probably do fire at slightly different times to extend the spark time and make sure all the fuel is burnt
Honda Owner
Falcoholic
Posts: 37
Joined: Fri Mar 20, 2020 5:33 pm
Has thanked: 46 times
Been thanked: 16 times

Re: Spark Plug Issues

Post by Falcoholic »

Julian_Boolean wrote: Tue Jun 02, 2020 4:08 pm Seriously lean mixture could cause that, but it would have effected both plugs and you'd have a hole in a piston.
The two plugs probably do fire at slightly different times to extend the spark time and make sure all the fuel is burnt
It runs lean anyway. I'm unsure how to richen the mixture using Tune ECU software. It looks like a black art to me. The other option is to fit Fat DUC O2 compensators which interfere with the voltage signal back to the ECU from the two sensors in the exhaust allowing more fuel to be provided. Not a massive job and reports by those who have them fitted they seem to make a considerable difference. Don't seem to be in stock in the UK at the moment. Ho hum.