Spark plugs

[Nick]

The threads on here for plugs are fairly old now.

I put  NGK BR7HS in when I bought the bike to run it in and have kept using them long after.

I see some run BR8HS normally

I need new plugs for this season and wondered if any one has tried the Iridium NGK?

They are supposed to withstand higher temperatures so was thinking of sticking with the direct replacement to B7HS  which appears to be BR7HIX they cost about 2 1/2 times as much but are supposed to need less current to spark so wondered if the bike would be better at slow speeds?

[Nick]

I mean B8HS

[Chris Exelby]

My bike was fitted with B7HS and they kept fouling up, requiring regular cleaning. I switched to the Platinum NGK B7HVX and they work day in day out, month in and out. In fact they have never fouled up.

In the quest for even better performance I have recently purchased some NGK BPR8HIX. They are Iridium  with the same narrow electrode and longer noses that will sit further into the combustion chamber and  operating at higher temperatures should be even better at self cleaning. Sorry but I have nothing to report yet!

[Chris Exelby]

NGK_Upgrades.pdf

I found this NGK 'upgrades' list very useful.

[Nick]

Thanks Chris have ordered some BR7HIX to try.
I wont fit them until I have put the bike back together and used it a few times to see if I can notice any improvement when I do.

Would be very interested to know how your new option works?

[hendred]

I have been running NGK BP8HS plugs for several years now.  The plugs have never fouled so far and seem to give better running at low speed/small throttle openings.  

[Smokey_Paul]

Funny I run Champion plugs but only because I managed to get hold of some gold upgrade ones and again never had an issue.
In fact I found them to run cleaner than the NGK B8HS!

[Nick]

My bike doesnt seen to like the iridium ones coughs and splutters on them with poor tick over.
Put the BR7HS back in and seems to run well and tick over fine!
Are you supposed to run the iridium with a larger gap or something?

[hendred]

I thought they used the normal gap. I have just replaced the NGK BP8HS plugs as the bike was getting hard to start.  Plugs looked fouled but had been in the bike for 3 years but not used at all last year.  Replaced them with Champion L4G gold palladium plugs and these were gapped at 20 thou out of the box. Left them as they were.  Bike started up straight away and settled to a nice idle.  Be interesting to see how they perform over the longer term. The NGKs ran very clean for some time so I expect the fouling started as the plugs began to fail.

[hendred]

Looking at Denso equivalent plug for another purpose and in their application table most plug gaps for 4 strokes is 0.6mm (24 thou) but for MZ 2 strokes it is 0.5 mm (20 thou).  It might be worth setting the gap on the iridium plugs at 20 thou and see what happens. Not come across this table before.
Hope it helps.