Cross Threaded Plug

[Jay B]

Question here. Its GS related (Well the bike is parked next to my GS so that makes it close) I have a 80 Yammie 850 Special that I store in the wintertime for a co worker. Last year she changed the plugs and cross threaded one(#4). Its seated completly, fires properly and comes out just the same as the other three. She was talking about it th other day and someone (an HD guy at work WHO just happens to do this kind of work) that she should have the head pulled, drilled, a heli coil put in and then be more careful with the plugs. Another guy (rides a 74 Honda 750) says that if she road it all last year, which she did (almost 5000 miles) and nothing broke that she should just let it go because she was lucky. The Yammie mechcanic I called said the same thing. I had a guy check it with one of those little cameras that fit almost anywhere (we have some neat toys at work) and he said that theres no scoring to the cylinder so she didnt get any metal in there. She trusts me as I take care of her bike all winter and wanted to know what I thought so I'm turning to my experts (you guys). Leave it or fix it?

[jimcor]

As long as it's seated and sealed without any blowby...I'd leave it.

[SqDancerLynn1]

Somethings are best left alone. If not You can heli coil it with out taking the head off if it needs to be done. Or just run a tap thru it to clean up the threads

[earlfor]

Re: Cross Threaded Plug

Sounds to me like the plug threads into the head just fine and seals fine. I would make it a point to always turn that plug in with my fingers so as to be able to feel that is is threading correctly.
Otherwise, leave it alone. It aint broke, so dont fix it. :-)

Earl

Question here. Its GS related (Well the bike is parked next to my GS so that makes it close) I have a 80 Yammie 850 Special that I store in the wintertime for a co worker. Last year she changed the plugs and cross threaded one(#4). Its seated completly, fires properly and comes out just the same as the other three. She was talking about it th other day and someone (an HD guy at work WHO just happens to do this kind of work) that she should have the head pulled, drilled, a heli coil put in and then be more careful with the plugs. Another guy (rides a 74 Honda 750) says that if she road it all last year, which she did (almost 5000 miles) and nothing broke that she should just let it go because she was lucky. The Yammie mechcanic I called said the same thing. I had a guy check it with one of those little cameras that fit almost anywhere (we have some neat toys at work) and he said that theres no scoring to the cylinder so she didnt get any metal in there. She trusts me as I take care of her bike all winter and wanted to know what I thought so I'm turning to my experts (you guys). Leave it or fix it?

[Anonymous]

cross threaded spark plug

hi jay, your problem is not fatal go to your local auto parts place and buy your self a thread chaser for your plug thread. start the thread chaser into the threads be shure to get it right , now remove the chaser and coat it with lots of grease any kind will do, the grease will pick up any shavings left from the thread chaser and you have better threads to work with. if left alone the threads get weaker every time you pull the plug. being no. 4 plug it should be an easy project good luck reg

[brs127s]

Hey Jay,

While I agree with the philosophy, if it ain't broke, don't fix it, I have to say go ahead and fix it. My reasoning is, first, it's winter, so you have down time. Second, it is going to have to be fixed sooner or later, depending on the next time the plug is removed. Since she trusts you to take care of it, you might as well do it, instead of someone she doesn't know.

[billp]

Funny, I seem to remember my 80 yamaha 850 being a triple.

bill

[Anonymous]

It will have to be fixed eventually, if the bike is kept long enough. But if it were mine, I'd let it go untill then. With the kind of unleaded fuel sold now days, very little, if any deposits should build up on the plug. I change my plugs every 2 years, and they come out almost like new. Too bad it wasn't a platinum plug, or better yet, iridium, you could really forget about ever bothering with it.