Author Topic: how to save a boogered up spark plug hole thread?  (Read 82 times)

Iahawk

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how to save a boogered up spark plug hole thread?
« on: September 07, 2026, 08:48:23 PM »
well...my Nighthawk 650 has been in pieces all summer. Today I decided to take my 3rd try at getting cams, sprockets, etc. back in with the correct timing. I successfully got everything installed and timed correctly! I was so happy. Started to put spark plugs back in and plug #3 was not going in easily by hand like the other 3. even with a ratchet on it it was taking more force than I was willing to put on it to get it back in. Removed and retried , gently, a few times. No luck.

Took a pic down the plug hole and you can see the threads messed up a little about halfway down. Ive posted this on my Nighthawk forum but thought I'd post here, too, as this is a relatively common engine problem. Any suggestions on how to proceed?  Thanks!  (hope Ruffus knows this forum is back online...)
2010 People S200 - sold after 8 wonderful years!
2014 Ninja 300
1996 Honda Helix
1984 Honda Nighthawk 650

Iahawk

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Re: how to save a boogered up spark plug hole thread?
« Reply #1 on: September 07, 2026, 10:12:47 PM »
all right, looks like I've found a solution...a back tap thread repair tool, for spark plugs! It is inserted in the plug hole, expanded then pulled back out while turning to chase the threads. It captures any metal because it is pulling out of the hole, not going in. Brilliant. Learn something new every day!
2010 People S200 - sold after 8 wonderful years!
2014 Ninja 300
1996 Honda Helix
1984 Honda Nighthawk 650

Neil955i

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Re: how to save a boogered up spark plug hole thread?
« Reply #2 on: September 09, 2026, 03:27:44 PM »
That sounds like a neat tool Hawk.
Regards & ride safe,
Neil

Current garage:  Kymco DTX360 & Triumph Street Triple 675R
Past bikes: BSA C15. Honda S/wing (GL500). Kawasaki GPz750. BMW K100RS. Kawasaki GPZ900R. Yamaha FJ1200 x2. Sprint. Triumph Daytona 900. Kawasaki ZX-7R. T595 Daytona. Kawasaki ZX-9R x2. Triumph Daytona 955i. X-Town

Stig / Major Tom

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Re: how to save a boogered up spark plug hole thread?
« Reply #3 on: September 10, 2026, 04:46:42 PM »
Is it removing much material?
Stig
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Rural Ohio

And, I'm feeling a little peculiar.

Iahawk

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Re: how to save a boogered up spark plug hole thread?
« Reply #4 on: September 10, 2026, 08:15:46 PM »
I don't think it is supposed to, as it is only a thread 'chaser' or 'restorer'...not a full on 'tap' which cut new threads.

Directions say to put grease on threads so it will hold any shavings it creates as you pull the tool up and out. Might give it a try tomorrow...Saturday and Sunday are already booked solid.
2010 People S200 - sold after 8 wonderful years!
2014 Ninja 300
1996 Honda Helix
1984 Honda Nighthawk 650