Trials Australia Forums

A quick question. Are iridium plugs worth paying 5-6 times the price of regular spark plugs. Currently i am running an NGK and have run Nippon Denso in the past. I have a sherco 290 08 with the keihin flatslide carb as is run on the cab. models.

Was just interested as had a plug die suddenly! It was in a near new 08 that has done very little work, put on my flatslide, so therefore the mixture should have been fine as it had run on my 06 for 6 months without issue. Perhaps is was the previous carb and runnning rich to run the bike in!

Thanks in advance

Howdy Y'all,

I have run iridium in my 2 stroke Scorpas and gave found them to be rubbish. Using a standard NGK I got a year before I changed it (only because I felt like it). I would get 1, maybe 2 trials from an iridium before it would start playing up then 2min later it would die.

I tried Splitfire and they were ok, but currently I use Bosch Platinum and reckon they are the ducks nuts. I think I got 4 sets of 4 (16 total) for about $50.00 from the US (this was 3years ago). I just can't seem to get through them because they last. I changed my last one after 15months, but only because I was looking for something to do.

Go std NGK or Bosch Platinum if your feeling saucy. Steer clear of Iridium plugs and spend your saved cash on lap dances or a new Scorpa.

Cheers,
Your friendly neighbourhood ScorpaMan,
Scorps

Hi sdeane01
I was having a lot of trouble with fouling plugs in our three Gassers (1/250-2/125's) I was using 98 octane (BP Ultimate).
I switched to 95 octane premium haven’t fouled a plug since.
That has been 12 months now we are using NGK BPR5ES plugs.
Hope this helps.
Phil.

My old beta would kill everything but them ngk i think they were iridium v plugs and standard one would last 2 months a champion/bosch etc would last a day

One thing a lot of people do not pick up on is there are two types of NGK Iridiums sold in Australia. There is a standard gap EIX and a large gap EIX . The large gap EIX is the most commonly found in Auto Parts shops, but the gap is way too BIG for modern Trials bikes. Check the code _ small gap will be say NGK BKR5 EIX (no numbers after the EIX)
large gap will be say NGK BKR5 EIX 14 (two numbers after the EIX)
both will work if gapped correctly, but if you chuck in a large gap iridium as it comes in the box you are wasting your $$$$$, and will be up for a new one in no time.
I have seen plenty of Iridiums used for incredibly long periods when gapped correctly. I rate them. IMHO.

Howdy Y'all,

Isn't strange how we rate the plugs. I found an old Iridium box around and I was using BKR5EIX-11 (bought from an auto shop) having said that I always gapped them @ 0.7mm. Still found them to be garbage.

I also found a Bosch box - It is a WR9DP (Bosch p/n 4220). Set the gap to 0.65mm and away you go (for an SY250) for 1/4 the price of an iridium. Worked beautiful for SY250 with TK and Keihin carby. Can't imagine why it wouldn't work in other 2 strokes 250 and above.

Cheers,
Your friendly neighbourhood ScorpaMan,
Scorps

I've only ever used NGK BPR5ES in my Gassers, and never had a problem. Swap it over at 12 months, "just because". Never had a need to even think about trying anything else.

I've used heaps of different plugs over the years and I changed to NGK 10 years ago. I first tried a correctly gaped Iridium plug in my SY in 06 and now I wouldn’t use anything else...

Paul Mac

On a Sherco, using 98 Unleaded, try a BPR6ES...it runs a bit hotter (just the plug) and keeps it's self cleaner that way. I've been riding (most days) with these for over 2 years and only changed 2 plugs in that time.

I also tried Bosch Platinum but 3 died on me in just 10 mins of riding....go figure


Best of balance.

Neo

Neo
Going from a heat range 5 to a 6 is actually going to a colder plug in the NGK plugs.
Please see chart attached.