Plug thread damaged...


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zalle
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Plug thread damaged...

Post by zalle »

Hello guys, It was over a year ago, but it's still there.

I put a spark plug at a slight angle and damaged the thread a bit. Yesterday I decided to look at it, so I took the tank and replaced the spark plug, I believe it's NUM 3.

I can screw it in, but eventually I'm using too much force and afraid to break something. It goes almost all the way in, maybe it's all in, I can't tell for sure, and it was dry around the thread when I removed the old spark plug.

Anything I can do without taking the engine apart?

Thanks

steve murdoch icoa #5322
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Re: Plug thread damaged...

Post by steve murdoch icoa #5322 »

TimeSert. Lots of good info here.
viewtopic.php?f=25&t=8642

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Re: Plug thread damaged...

Post by Larry Zimmer »

steve murdoch icoa #5322 wrote:
Sun Jun 21, 2020 9:25 pm
TimeSert. Lots of good info here.
viewtopic.php?f=25&t=8642
TimeSert is great. Gotta pull the head, though. I can't think of any other solution to this one.
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Re: Plug thread damaged...

Post by EMS »

I have repaired spark plug threads without removing the head on both bikes and cars:
- Move the piston to TDC
- Smother a long piece of thick string with grease
- Stuff it into the plug hole on top of the piston
- Cut and repair the threads, put as much grease as possible in the grooves of the drill and the tap, cutting carefully, remove your tool often to retrieve metal chips
- Pull the string out carefully with tweezers, getting all the rest of the chips out that will stick to the string.

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Jeff Bennetts
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Re: Plug thread damaged...

Post by Jeff Bennetts »

This topic came up a few months ago on another forum and someone mentioned this neat little thread tap, so cool that I had to add it to my tools.

Here's a link and description of the tool!
https://www.jegs.com/i/Powerbuilt/211/641148/10002/-1

The back-tap's patented collapsible design allows it to engage be placed through the spark plug hole and into the chamber. A mandrel is then drawn back expanding the tool's threaded area and threading into the clean threads at the bottom of the spark plug hole. The Backtap repairs the damaged threads as it is drawn up through the spark plug hole bringing debris and metal filings with it. Made in USA and comes with a lifetime warranty.
Back-taper 12 millimeter thread straightening tool for motorcycle spark plug fouled threads
Collapsible design allows it to engage be placed through the spark plug hole and into the chamber
Expands the tool's threaded area and threading into the clean threads
Built to exceed tool standards
Highly durable
Back-Tap 12 millimeter thread straightening tool for motorcycle spark plug fouled threads
Collapsible design allows it to engage be placed through the spark plug hole and into the chamber
Expands the tool's threaded area and threading into the clean threads
Backtap repairs the damaged threads as it is drawn up through the spark plug hole

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Re: Plug thread damaged...

Post by Larry Zimmer »

Those are both great. Thanks Mike and Jeff. (Hope I never need to. However, great info.)
Larry Zimmer
cbxlarry@sbcglobal.net

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zalle
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Re: Plug thread damaged...

Post by zalle »

The powerbuilt tool just arrived today. Looks pretty sturdy!

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Re: Plug thread damaged...

Post by Jeff Bennetts »

zalle wrote:
Wed Jul 01, 2020 2:53 pm
The powerbuilt tool just arrived today. Looks pretty sturdy!
I haven't used mine yet, let us know how it goes!

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zalle
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Re: Plug thread damaged...

Post by zalle »

It went bad!

I broke it inside. Not as sturdy as I thought it was.
I think it has a design flaw. You're supposed not to open the thread all the way in the first couple of passes, but the adjustment is not precise, so you don't know if you're opening too much or not.

I've spoken to my mechanic, and I'm sending it next week 🙄

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Re: Plug thread damaged...

Post by steve murdoch icoa #5322 »

Sorry to hear that, Zalle.
Does your mechanic think he can salvage the repair or is the head coming off?

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zalle
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Re: Plug thread damaged...

Post by zalle »

He says there is a chance. Let's see what happens.

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Re: Plug thread damaged...

Post by CBX546 »

🍿

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zalle
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Re: Plug thread damaged...

Post by zalle »

He managed to take it out!!!!! The guy is a genius!
He used strong magnets, I think.

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Re: Plug thread damaged...

Post by steve murdoch icoa #5322 »

Glad to hear it.
Assuming you mean he got the broken tool out?
Is he going with a TimeSert to repair the threads?

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Re: Plug thread damaged...

Post by AshishNJ »

I that must be a big relief :). Otherwise you were looking at new head
1979 CBX (faster Red)
1981 CBX Streetfighter
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Past rides : FZ1, BMWS100rr,S1000r,k1300S,YAMA RD350,Enfield 350

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