Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: royhall on June 08, 2019, 04:43:53 PM

Title: Spark plug threads
Post by: royhall on June 08, 2019, 04:43:53 PM

I have a CB350F thats had a seized spark plug thats been removed, but now has a damaged thread. The thread will take a plug and torque up okay but I don't want to risk it if I don't have to. What's the best way of repairing this thread preferably not with a helicoil, as these have a habit of winding back out everytime the plug is changed. Cheers.

Title: Re: Spark plug threads
Post by: Nurse Julie on June 08, 2019, 05:06:39 PM

Timesert. It think it is Moorey that bought a specific kit for plug threads that he used with great success on one of his bikes.

Title: Re: Spark plug threads
Post by: royhall on June 08, 2019, 05:43:27 PM

Thanks Julie. Just had a look at the Timesert system on YouTube. Looks pretty good, and simple to do as well. Way better than Helicoils. I do have a choice of heads but I don't want to waste one when it could be repaired. Cheers.

Title: Re: Spark plug threads
Post by: Moorey on June 08, 2019, 05:46:52 PM

I repaired the head on my 175 with one of these. A piece of piss to do and has been fine since that was in 2017 and I was out on that bike last week so I know its still good. I didn't take the head off to do it either but that's up to you. I don't like buying gasket kits if I don't have to. I am a Yorkshireman after all.  ;)
https://www.ebay.co.uk/itm/Vorlux-by-Bergen-Spark-Plug-Thread-Repair-Kit-M12-X-1-25-NEW-5838/152612536284?hash=item23886a7fdc:g:flUAAOSwopRYiNK0

Title: Re: Spark plug threads
Post by: andut on June 08, 2019, 05:51:30 PM

Ideally it's head off and a Wurth Time Sert, but they're not a cheap kit, plus new head gasket etc.  Faced with a similar problem a few years ago, I tried a Vcoil repair kit (Helicoil copy) without removing the head and all is well a few hundred miles later.  Obviously a risk with  cutting a thread without removing the head and potential to wind the insert out when removing the plug, but my experience has been good so far.

Andy

Title: Re: Spark plug threads
Post by: Moorey on June 08, 2019, 06:05:04 PM

http://www.sohc.co.uk/index.php/topic,13481.msg106347.html#msg106347

Title: Re: Spark plug threads
Post by: royhall on June 08, 2019, 06:13:36 PM

Quote from: Moorey on June 08, 2019, 06:05:04 PM

http://www.sohc.co.uk/index.php/topic,13481.msg106347.html#msg106347 (http://www.sohc.co.uk/index.php/topic,13481.msg106347.html#msg106347)

Just read the above link. That all makes sense, am going to give it a try. The Wurth kits look the superior system but are silly money. Thanks Moorey.