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spark plug thread

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when i tighten my spark plug it will not go tight enouth it will just keep turning. it does go tight enouth so i can ride the bike..

what shoud the fist thing i try to fix this? try to tap the thread with the head on

or do i need to take the head off realy

did a search and only found a thread about heli coiling the head cover threads

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You will need a helicoil to fix it.

More experienced people will add to this, as I have never had to do a helicoil for a spark plug I can not advise with authority but I'm guessing it will be to deep to access with the head on the motor, I might be wrong.

Good Luck.

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I would not recommend a Helicoil for a thread that has to be often disassembled. Time-cert (SP?) is much better. It is a thread bushing that is expanded and locked into place with the kit tools.

Take the head off and take it to a shop with the proper tools. They will have to evaluate if there is enough room for a thread repair between the valve seats.

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You are aware I assume that the original spark plug thread in a DRZ400 is 10mm X 1mm thread. Why would you use a 12mm Helicoil? If you could actually fit a 12mm plug, you don't need a Helicoil.

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yeah i just got mixed up...the socket size is 12mm

Err, nope.

Standard plug

NKG CR8E

Thread 10mm

Reach 19.0mm (3/4”)

HEX 5/8” (16.0mm)

And for the record, I most times prefer Heli coil over time serts. As for not using them in thread holes that see a lot of use,, I respect Nobles position and experiences, but in this we differ on two points.

1: I dont consider a spark plug an item being installed and removed often.

2: In 35 plus years of installing Heli coils in my vehicles and 10's of hundreds of others, I've never seen an issue with them due to being used in a location that had high install, removal rates of the fastener of component part.

We are a conglomeration of our training and personal experiences, those are mine.

To the OP, remove the head, if your confident in your skills, the install is minutes of work.. If even slightly unsure, take it to an automotive machine shop. repair will be quick, sure, and likely done cheaper then you can do it your self if your buying the kit and tools for this one job.

Having had botched broken fastener and thread repairs brought to me for a fix.. I can say, having it done at a shop is MUCh cheaper then bringing in the botched job and having it fixed.

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Call around to your local motorcycle shops and find out which machine shop they use. They will likely have the right Heli-Coil in stock. When I had a broken stud, three local bike shops all recommended the same machine shop, and they did a great job.

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Call around to your local motorcycle shops and find out which machine shop they use. They will likely have the right Heli-Coil in stock. When I had a broken stud, three local bike shops all recommended the same machine shop, and they did a great job.

will ask my local bike shops any way..i do like doing things my self so if it a bit cheaper do do my self i will

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