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Staubig

CB750 Enthusiast
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I have a 79 cb750 Limited. I'm replacing both ignition coils (one is faulty), the cables, and upgrading to iridium spark plugs.
From NGK D8EA to NGK DR8EIX

My question is this:
Should I gap these plugs, do I need to?

I'm in a toss up. The clymer that came with my bike has specifications for gapping, which is awesome. Unfortunately, iridium plugs didn't exist when the Clymer or bike was made. Should I follow manufacture's specifications, or leave it be? I've heard they're easily damaged and with the extra "power" I wasn't sure I'd need to account for a gap.

So those of you who have switched please chime in!
 
I've always heard that you should leave the pre-gapped plugs alone for iridium plugs. What is the spec in the manual and what are the plugs? If the difference is minor I would run them as they are.
 
You can gap them if you use the type of gapper that hooks the eletrode to bend it...Not the wedge type. If you use the wedge type you will break or chip off the iridium. Most of the time they are in spec but boxes can be dropped etc. Honestly there is no point in using iridium in these old bikes. I have actually run into fouling problems with them when I tried one in my dirt bike. When I worked in an automotive shop we never liked to install them either, they seemed to cause missfires far easier then standard or platinum plugs did.
 
The manual days .05-.06, i believe. I knew not to be rubbing up in the Iridium post, but wasn't sure if they "needed" gapped due to the supposedly Mord powerful spark. I wish i had checked in Herr first before i bought them! Ive got a fresh set of regular ole' NGKs if these turn out to not perform well. I'll check them with feeler gauges and gauge them if they're way off. Thanks guys.
 
These bikes use waste spark systems that fire one plug of each pair BACKWARDS. Iridium is only on one end of the plug or they would be 'double' iridium like double plats which have it on both ends. Waste of money on these plugs as the only thing they give is true 100K use, the bike will never last that long.

You ALWAYS at least check new plug gaps, what you do to correct them is your issue but I saw so many dropped to alter them I cannot say. Plugs get dropped all day long at the parts stores.
 
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