Proper spark plug gap size

Rusty_Nail

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Oct 11, 2019
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Hi everyone. My sparkplug that came with my kit appears to not be gapped at all. What is the proper gap size or can I just go to autozone and buy right size spark plug. I've never had to gap a spark plug so need some help. Thanks!
 

wrench

Active Member
Aug 20, 2019
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So Cal
Ok. It is common for them to come ungapped? What tool do I need to gap it? I'm a noob at this.
A feeler gauge or a S/P gap tool sold at all auto parts stores.

Since ya asked what tool to use to gap the S/P it sounds like ya don't have a feeler gauge or a S/P tool

You can also use your D/L or Credit Card as the plastic is .025" to .030" thick
It's always good to know that ya have something handy to gap your S/P if ya don't have a feeler gauge.

Your motorbike engine S/P gap should be .025" or .030" This will be fine.
 

Rusty_Nail

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Oct 11, 2019
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What is safe to use to bend out the little arm without breaking it? Would like to keep it as a backup. But for now will probably just get a new one.
 

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wrench

Active Member
Aug 20, 2019
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So Cal
That S/P ya have is fine just gap it.
Yes, buy another NGK S/P for back up.

A S/P tool is best, as it has a little notch on it to bend the little S/P tab.
But you can bend the little S/P tab up with any thing ya got handy. Just don't pry against or put pressure on on the electrode or ceramic insulation as ya might break it.
 

wrench

Active Member
Aug 20, 2019
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So Cal
What is safe to use to bend out the little arm without breaking it? Would like to keep it as a backup. But for now will probably just get a new one.
The wires are different gauge size for gaping spark plugs
The notches are for bending different thickness S/P tabs

As you can see i have the .025" gap wire marked with an arrow as that's the one I use most.

DSCF3463.JPG
 

Larry Trotter

Active Member
Nov 26, 2017
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Don’t overthink the problem. Your plug is fine. Grab the little tab with pliers and open the gap to about the thickness of two match book covers. It will run fine. When starting out a smaller gap is better than one that is too big but most any gap will make it run.
 
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wrench

Active Member
Aug 20, 2019
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41
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So Cal
Not any gap will do to get a proper spark from spark plugs. Sure your bike might run but it will probably run like sh*t.

Spark plug gap should be between .020" and .040"

Narrow S/P gap - The duration of spark has less travel distance, thus not remaining hot enough to ignite fuel air mix. Causing misfiring, hard starting, hesitation.

Excessive S/P gap - The increased length the spark has to travel weakens the spark. The spark will jump to the side of the spark plug too, preventing a strong spark. Causing misfiring or a no start condition

TIP:
If ya don't have a feeler gauge or a S/P gap tool to set the correct S/P gap use your drivers license or credit card as the plastic thickness is between .025" and .030"
 

Rusty_Nail

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Oct 11, 2019
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OK guys. One more thing. Yesterday I went to both AutoZone and O’Reilly auto parts and it seems like none of these places have the right spark plug for these engines where else can I get them?
 

Greg58

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May 1, 2011
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You can have them cross reference B6HS to autolite at AutoZone, they run pretty good but not as good as the NGK. As was said above gap the stock plug and use it while they order the proper plug.
 

Greg58

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May 1, 2011
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Larry some of the kit supplied plugs are just something they drop in the box, some don't cross reference to anything close to the NGK. I know the NGK works, my oldest engine is now 10 years old and has been running one since day one, it came with the three prong plug.
 

Larry Trotter

Active Member
Nov 26, 2017
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Thing is he is expending lots of energy worrying about nothing while he could be building his bike. He will have plenty more important things to figure out before he even needs a spark plug of any kind. What he has in the kit will make it run.
 

wrench

Active Member
Aug 20, 2019
136
41
28
So Cal
OK guys. One more thing. Yesterday I went to both AutoZone and O’Reilly auto parts and it seems like none of these places have the right spark plug for these engines where else can I get them?
An auto parts store should be able to order one. I'm surprised they didn't offer to order it.
M/C shop, Lawnmower shop, Go Cart shop Or order on line There very common