Any idead how long a helicoil for my sparkplug should be??

[Tristan]

Hey guys,

I've stripped a sparkplug hole on my cb350f and have purchased a helicoil kit, but it didnt come with any inserts. I'm out of town on work, so I can't take any measurements on the bike. Does anyone know how long the threads on a sparkplug are? There's just so many options for length and I dont want to screw up and get the wrong length.

Appreciate it as always

 

[Sonreir]

Which bike? Different plugs have different reach lengths.

 

[Tristan]

1973 cb350f

 

[Sonreir]

12.7mm is the reach on the plug, 12.5mm helicoil should work OK.

 

[Tristan]

Thanks Sonreir! Now to find it somewhere online!

 

[crazypj]

Are they 10 or 12mm plugs?
Ebay has metric inserts
http://www.ebay.com/itm/HeliCoil-Metric-Inserts-Many-Sizes-Available-/260826049183?pt=LH_DefaultDomain_0&var=&hash=item3cba71aa9f

 

[Tristan]

12mm

 

[crazypj]

I should have remembered, I've got one ;D
I'll check pitch and length later, there are at least 3 different pitches for 12mm thread (1mm, 1.25mm, 1.5mm)

 

[Sonreir]

1.25 on these.

 

[crazypj]

I'm not doing so well this morning

 

[Tristan]

Yeah, it's 1.25.

 

[teazer]

I'm not doing so well this morning

I don't do mornings......

If the plugs are D8HS like the 175 twin, they are indeed 12mm * 1/2 inch reach (12.5mm)

750 is also 12mm but 3/4 reach and fitting those by mistake stops valves from opening - don't ask how I know . It was morning and I was late for first practice and fouled a plug, so I just grabbed one and in it went. End of play.

 

[crazypj]

'H' is short reach (1/2")
'E' is long reach (3/4")