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[RocketRR]

Just a quick note I changed my Indian Bosch spark plug tonight for a new Ngk and to my surprise when I removed the spark plug cap it fell off in my hand. It had not been fitted perfectly at all so lucky I caught it before it failed. Just a warning this 5 minute check may save an unnecessary break down. Check your lead and screw the cap on properly I was lucky this time.
Cheers RR

[jefrs]

Exactly the same thing here on Classic 2015. HT cap not screwed onto HT lead, it's a screw not push fit. The HT Lead is not replaceable, it is moulded into the coil and my HT lead was a trifle short thus it must have pulled out; I repositioned the coil to give it some slack. I discarded the oem HT cap and fitted a NGK non-resistor type which requires a NGK "BPR" resistive plug. CGT uses the pos Bosch-India WRQ8DC which is R for resistor, Q for quick-heat, 8 is equivalent to BPR6ES for lawnmower or BPR5ES for cars. Bosch 7 & 8 are given as equivalent to NGK 6 but NGK 5 is given as equivalent to Bosch 8, go figure. NGK do make the BP6ES/BPR6ES for lawnmowers, how can I put it, they look less elegant than the BPR5ES Vauxhall Nova plug, prolly less QC. The NGK 5 is a little hotter but the nose is burning exactly the right colour on mine (EFI-500, K&N, free-flow, PCv) N.B. YMMV!

[jefrs]

And don't use the NGK irridium, many tales of woe with that one.

[Beezabryan]

Is that right!
Funny old thing really, there has been an NGK Iridium in our old Bullet since 2010

[RocketRR]

Thanks all I fitted a BPR6ES I may as you say fit an NGK plug cap if I see one at Shepton Mallet at the weekend.

Cheers

[Presto]

I don’t buy into this idea that iridium plugs are ‘suspect’ in themselves. I wouldn’t use any other than iridium plugs in my engines. Far better option than the alternatives. If an iridium plug fails prematurely and regularly I’d suggest that is likely to be due to the wrong type/heat range being chosen or something radically wrong with the engine set-up. As many folk have rightly pointed out on this site, it’s precarious with modern fuels to try to ‘read’ plugs as we used to in the past. The visual results can be misleading. But all this is just my (considered) opinion!

[nigelphoto]

Here we go again . . . I've posted this before in a previous thread on spark plugs. This is from our hosts "Technical Notes - EFI 500. There seems to be some confusion over the special spark plugs fitted as standard to EFI 500 engines. The standard plug is an Indian made 'Bosch' item (WR7DDC4) with two side electrodes and a unique heat range. There are websites that suggest equivalents as replacements for the standard item. Having made detailed enquires with the world's leading spark plug manufactures we have been told there are no equivalents currently available. Our own tests confirm this, with alternative plugs producing poor performance - or worse!". I have also contacted Watsonian Squire, importers from 1999 to 2013 who confirmed that they only fitted the Bosch WR7DDC4 to any EFI engine and more than that they sent some Bosch plugs to NGK who confirmed in tests that they could not supply an equivalent. You will find the NGK is about 2mm longer than the Bosch, placing the flame front closer to the piston and thereby causing a localised heat spot . . . . OK, OK I'm only saying what people of far more technical knowledge and experience of LIFE have told me!

[ric]

I'm guessing the BR6ES doesn't have this problem because without the projected tip the BPR6ES has,it's almost about the same length as the OEM Bosch

[RocketRR]

Our hosts list the Iridium as an upgrade plug for the GT??

Who knows ???