Topic: Plugs and Threads

[TheHulk]

The #3 cylinder plug on my 77 CB550 makes me nervous.

I've successfully removed and installed new ones a few times, but I'm afraid of stripping the threads eventually. All other plugs I am able to hand tighten all the way to the crush washer, but #3 requires a wrench for every turn.

Would a little bit of never cease on the plug threads dirty up the cylinder? Would motor oil do the trick instead? Would removing a plug from a hot vs cold engine be better in the long run? Anyone with common issues or suggestions? Thanks!

[HondaMan]

I used grease or anti-seize on all plug threads, every time.
The 500/550 has troubles with the #3 sparkplug because of the nearby tach drive: the Honda toolkit came with a special tapered-top sparkplug wrench just for that reason. This wrench clears that tach drive so you can use the screwdriver's insertable shank as your torque-tool. If you don't have that wrench, maybe try to get one at the local bike junkyard: many other bikes copied the method after that.

[Duanob]

I made my own tool, works better in all 4 pots. And yes I use antiseize also in all my vehicles. Steel threads in an aluminum head, if left a while can corrode due to being bi-metal.

[Kelly E]

We use a 12" length of 3/8" fuel line to install and remove spark plugs. It allows you to get the plugs started without cross threading them. If it tries to cross thread you can feel it.
We use the Honda tool to loosen and tighten the plugs. We use the same Honda tool on most of our bikes no matter what brand the bike is.

[PeWe]

I use aluminium paste on my plugs. It withstand +1100*C

Just a little on the threads.
I like to tighten plug down mostly by hand.

New plug will get a little paste on its thread.
I use the std tool Honda delivered in the CB750 tool box.

[willbird]

I just use clean fully synthetic motor oil on the threads myself, have had no issues so far.

Bill

[bryanj]

Coppaslip for the last 50 years

[madmtnmotors]

I use the Craftsman version of this thread restorer kit for many threaded holes in aluminum:

https://www.amazon.com/Thread-Chaser-Repair-Rethreading-Restorer/dp/B0BH8QSHTF/ref=asc_df_B0BH8QSHTF/?tag=hyprod-20&linkCode=df0&hvadid=692875362841&hvpos=&hvnetw=g&hvrand=11216617108048682754&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1015150&hvtargid=pla-2281435178578&mcid=de492933fd79386891b8c541fe5af30d&hvocijid=11216617108048682754-B0BH8QSHTF-&hvexpln=73&gad_source=1&th=1

 They are much less aggressive than a standard tap and they tend to "push" threads back into place as opposed to cutting. As with all things threaded into aluminum you must start slowly and ensure that the tool is straight and true. I get so much use out of mine that I actually bought the bigger set too.

[TheHulk]

I used grease or anti-seize on all plug threads, every time.
The 500/550 has troubles with the #3 sparkplug because of the nearby tach drive: the Honda toolkit came with a special tapered-top sparkplug wrench just for that reason. This wrench clears that tach drive so you can use the screwdriver's insertable shank as your torque-tool. If you don't have that wrench, maybe try to get one at the local bike junkyard: many other bikes copied the method after that.

Thanks as always HondaMan! I'll look into this tool. I have a semi custom one that seems to fit in correctly, but I'll keep investigating.

Thanks everyone else as well!

[Deltarider]

Coppaslip for the last 50 years

Same here, be it 44 years.