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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: Udor1234 on August 28, 2025, 08:25:47 PM
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Hi. Was investigating massively rich fuel burning on starting, so pulled plugs 1 & 2, yep loads of fuel on both. Went to pull 3 and it snapped off. Plug must be ancient. About 3mm of the body is sticking out, can pliers on it. Unsure if this is possible to get out. Any ideas?
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Cylinder head has to come off to remove the debris from the cylinder (if the porselin broke inside the engine). There is a tool called threaded plug chaser which can be used to remove it. Otherwise pliers, heat, wd 40 and hope and prayers to get the threaded part out, depending on what you have left over to work with.
But mostly. how even.
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You can remove that. You need penetrating fluid like Liquid Wrench, Kroil, or PB Blaster, a small Mapp gas torch, an extractor of some type—homemade or manufactured, an extension magnet, a shop vac with a flexible wand extension to clean out the cylinder, a borescope to inspect the piston and cylinder, and patience. This is a slow and methodical process. There a lot of people out there who have removed broken plugs, successfully cleaned the piston and the bore above the piston without removing the cylinder head, and ridden away, eventually.
This is the degree of patience needed to succeed. You've got it easy because you don't need to contort to work like this guy. Watch the entire video.
https://www.youtube.com/watch?v=JijVI3RTkMY (https://www.youtube.com/watch?v=JijVI3RTkMY)
My method over the last few decades looks a lot like his—using a rectangular extractor before breaking an easy-out; pouring on the penetrant; cooling the penetrant; repeating the heating and cooling cycles for an extended period; using force and being aware of when to stop before something breaks.
I like how he uses heat and then refrigerant in cycles. I just use the penetrant to cool but it makes for a lot of smoke and it surely is a health hazard in California. I suggest you get Mapp gas—it's hotter than propane and almost as effective as acetylene without being hellacious—and a couple of cans of Freeze Off for the cooling to lessen the smokey effect of applying penetrant, but I've found spraying penetrant on a hot threaded joint aids penetration of fluid as the joint cools. Heat and volatile chemicals can be fatal so be aware; you're about to enter the danger zone.
After the extraction, he used the engine to blow out the debris after using the magnet and vacuum. Disconnect the primary ignition wire before you do that to prevent starting. His method took a day of repetition—subtract the failed extraction tools from that time.
There is a wide selection of extraction videos. Select from these two lists. 1 (https://www.youtube.com/results?search_query=removing+broken+spark+plug) 2 (https://www.google.com/search?client=firefox-b-1-d&q=Removing+broken+spark+plugs&sei=WJmxaP2CNIOhptQPjuCkyA4) A lot depends on your patience, your attention to detail and your willingness to take risk. Just don't let your technique become chaotic. :laughing4-giggles:
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Just don't let your technique become chaotic. :laughing4-giggles:
Errr yes. Chaos
Also thats what i said just in less words.
But most of all. Good luck. Also dont do it again.
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Thanks gents. I think I'll get a pro out here to try and pull it.
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That's disappointing. We need some excitement around here. Nevertheless, good luck with it!
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That's disappointing. We need some excitement around here. Nevertheless, good luck with it!
Just 2 maybe 3 more months, then servicing and project season will start. And after that the failed-resold-problem projects will come