Spark plug gaps?

[Nick dj]

Just ordered a set of plugs for a twin cam and wondered do the twin gaps need setting? you do usually need to gap plugs.

I have youtube`d the fitting and they just unboxed and fitted them.

Any ideas?

 

[Smug]

If they are iridium don't try to gap.

 

[Santa-2512]

Prolly a daft question, but

How do you gap multi electrode plugs?

Flat to flat for a standard plug ... fine...


But multi's mean radius to flat ... room for error, or is it not that uber important ?

 

[UturnTony]

If they are iridium don't try to gap.

Which iridium plugs do you know are recommended for the Twin Cam?
I, so far, haven't been able to source any.

Prolly a daft question, but

How do you gap multi electrode plugs?

Flat to flat for a standard plug ... fine...


But multi's mean radius to flat ... room for error, or is it not that uber important ?

I just clean them inside around the insulator and the electrodes then set the gap between the centre and earth electrodes.
Works for me.

To the OP. I think you will find they are pre gapped but, you could run a check if minded.

 

[IrishGaucho]

I bought the spark plugs as per owners manual and fitted them right in, not a single problem.

 

[Bendy toy]

Open box, remove cardboard tube, fit plug. Repeat until all four are done.

They only spark from one electrode at any one time. The extra tips just share the wear. I've used mine with same spec single electrode plugs no change that I could detect but they were dead at 10,000 miles

 

[Mistacat]

"Which iridium plugs do you know are recommended for the Twin Cam?
I, so far, haven't been able to source any."


I tried the Denso iridium plugs as others have used in the Twin Cam.
I machined the end three threads from the end of the plugs to replicate the stock plugs.
At 12K miles they seemed ok at 18 K miles the iridium electrodes were gone. So not a replacement!!!
On the Pre Twin Cam 40 K miles no problem from Iridium plugs.
So like you I am still waiting for a proper Iridium replacement.

 

[Bendy toy]

If you leave a set of plugs fitted for 40,000 miles it's likely the secondaries will never come out again. They need to be removed and checked at every service if only to keep the threads from seizing. Primaries are protected from weathering so less of an issue.

 

[UturnTony]

If you leave a set of plugs fitted for 40,000 miles it's likely the secondaries will never come out again. They need to be removed and checked at every service if only to keep the threads from seizing. Primaries are protected from weathering so less of an issue.

I guess he like me takes them out, looks at them, cleans them then puts them back at regular Intervals and they still looked good at 40k.

 

[Mistacat]

I guess he like me takes them out, looks at them, cleans them then puts them back at regular Intervals and they still looked good at 40k.

That is exactly right.
I tend to go over the top when servicing.

 

[Smug]

If the plugs are done up tight, they will not seize.

Plugs usually seize when the they are not tightened down properly allowing the exhaust gases to leak past the threads. When this happens the plug will seize into the head.

 

[Bendy toy]

If the plugs are done up tight, they will not seize.

Plugs usually seize when the they are not tightened down properly allowing the exhaust gases to leak past the threads. When this happens the plug will seize into the head.

I was told the same - but Yamaha 900 (aircooled) would size it's plugs if left for more than 10,000 miles. GS not so bad but I dont trust it. Plugs always fitted with torque wrench. It only takes a moment to pull the plugs so I always do it when changing gearbox oil.

 

[Nick dj]

fitted!!!

Thanks for all the replies and entertainment!!!

Just fitted the new standard plugs an easy job. The plugs had 20k on and were visibly knackered, I would change them at 12k as BMW recommend or fit Iridium as I know they last longer, its not snake oil if even NGK say they are better and cost the same as the overpriced standard twin electrode ones. imho!!!!

 

[Bendy toy]

They only spark from one electrode at a time so in theory a 4 point plug should last 4x as long.

 

[adventuredon]

I guess he like me takes them out, looks at them, cleans them then puts them back at regular Intervals and they still looked good at 40k.

Had mine changed about 4k (10 months) ago as per service interval. Bike is currently (still) at BMW under investigation for intermittent cutting out and other faults etc, but they have said the plugs are shot. So that's a start...

 

[UturnTony]

Had mine changed about 4k (10 months) ago as per service interval. Bike is currently (still) at BMW under investigation for intermittent cutting out and other faults etc, but they have said the plugs are shot. So that's a start...

Shot at 4k That is very unusual Don.
The ones in my bike have done 24k to date and are still going well
and that's been the story across all the GS's i have owned.

 

[adventuredon]

Any idea what could be the cause of plugs going out of gap in such a short space of time?

Sent from my SM-G920F using Tapatalk

 

[Nick dj]

wow

WOW Tony and I thought I was a tight Yorkshireman getting 20k out of a set!!!!
Even I would recommend replacement now.

I can see a challenge here to others as to how many miles you did before failure (which could be expensive)

 

[rubas]

Which iridium plugs do you know are recommended for the Twin Cam?
I, so far, haven't been able to source any.


I use Denso IU24A in my 2012 R1200GSA, but you need a thin 16mm spark plug tool.

 

[Bendy toy]

I ran mine with single electrode plugs. Ask your supplier. they exist in the same threads and heat ratings. Quad electrode plugs have a longer life but you can feel fulfilled when you've set the gaps.