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1Back to top Go down   Cross threaded spark plug Empty Cross threaded spark plug Thu May 17, 2012 6:36 pm

rosskko

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I am in the middle of stripping the bike to clean it up and make it shiny. (86RT)
Just about to drop the engine and have the frame cleaned and resprayed.
I have had a cross threaded spark plug since I got the bike.
Took them out one day and number 4 plug turned 1/2 - 3/4 turn and fell out so I am guessing a crossed thread.
Should I remove the head (timing cover already off to check the chain condition) or helicoil or ignore?
The plug seals well and does not leak anything out from around it.
thanks
rossco

    

2Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Thu May 17, 2012 6:56 pm

Rick G

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You may be able to get someone to helicoil it while in situ but it is a very deep spot to get at. Fix it, one day it will come out and it will be a long way from home you can bet on that.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

3Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Thu May 17, 2012 8:56 pm

Two Wheels Better

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I drove my '69 Beetle around for a week or so after cross threading a sparkie, which was only a 1/2" reach compared to our bike's 3/4" reach. When the plug let go, as I crossed an intersection at the lights, it sounded like a gunshot as it blew out, taking all of the threads with it. I didn't know about Helicoils in 1980, or if they even existed back then, so I threaded a steel insert in and it was good to go for another year or so. I'd fix it, as Rick suggested, lest you find yourself with a four cylinder K75 at the roadside, only it won't be as smooth.


__________________________________________________
The forest was shrinking, but the trees kept voting for the axe, for the axe was clever, and convinced the trees that because his handle was made of wood, he was one of them. -Turkish proverb
1977 R75/7-100, '93 K11/K12 Big Block, '93 K1100RS, '95 R100 Mystic, '96 K1100RS, 2 x '98 K1200RS, '06 K1200R & '09 K1300GT
    

4Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Thu May 17, 2012 9:05 pm

beanoldboy

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"lest you find yourself with a four cylinder K75 at the roadside, only it won't be as smooth."
Good call mate.

http://www.airware.com.au
    

5Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Thu May 17, 2012 10:14 pm

nino

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Find qualifi ed metal workshop and ask there. Maybe could be enough to remove plug and renew the thread. Once I had same problem with old boxer 50/5 on one of the cilinders. We removed plug put the thread tap, drove it through the tread and that was enough.



Regards

    

6Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Thu May 17, 2012 10:22 pm

nino

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nino wrote:Find qualifi ed metal workshop and ask there. Maybe could be enough to remove plug and renew the thread. Once I had same problem with old boxer 50/5 on one of the cilinders. We removed plug put the thread tap, drove it through the tread and that was enough.



Regards

Put grease on the tap to pick fine debris from thread

    

7Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Fri May 18, 2012 9:46 am

rosskko

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If I am pulling the head off I was thinking of running the plug or a tap from the inside out?

rossco

    

8Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Fri May 18, 2012 2:07 pm

nino

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rossco wrote:If I am pulling the head off I was thinking of running the plug or a tap from the inside out?

rossco

Its much easier with head out of place, but you can try with head in place. Thread is deep inside if you do it for first time, ask somebody skilled to do it. Grease tap and run it down and back. It probably should be enough

    

9Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Fri May 18, 2012 7:08 pm

rosskko

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So after I ask the question, if I said I had less than no idea about removing the head I would be over stating how much I know.
I just spent 30 minutes staring at it wondering how in the hell do I know how it goes back together.
If I take off the timing chain (as I will have to) and if the camshaft gets turned while the head is out, how the hell do I make sure its all in the right spot again.
Crap.
Just realised.
The phrase 'bitten off more than I can chew' comes to mind

    

10Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Fri May 18, 2012 7:59 pm

Two Wheels Better

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Stop. Don't do it without help. If you run a tap through the threads in the head you are only recreating a non-crossed thread in the tiny bit of aluminium that is actually holding the spark plug in there....It needs to be thought through carefully, and you need advice from someone 'on the ground', and looking at it. Removal of the head is the last resort. A Helicoil or steel insert is what is needed to be considered first. I urge you to get some help.


__________________________________________________
The forest was shrinking, but the trees kept voting for the axe, for the axe was clever, and convinced the trees that because his handle was made of wood, he was one of them. -Turkish proverb
1977 R75/7-100, '93 K11/K12 Big Block, '93 K1100RS, '95 R100 Mystic, '96 K1100RS, 2 x '98 K1200RS, '06 K1200R & '09 K1300GT
    

11Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Fri May 18, 2012 8:20 pm

caferacer62

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Find yourself a good bike shop or one that rebuilds engines. They should be able to do it insitu. The engineering shop i last worked at had one, its a special kit for rethreading spark plug holes. It comes with a cutting tool the screws into the head (It has a self centering thread to go into crossed threads) it cuts a new deeper seat in the head and comes with special threaded inserts that lock themselves in once installed.
As GITH said if your not confident don't tackle it on your own.


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Bert 2.0

Don't give in to the Black Dog!
"A Zorst, a zorst my kingdom for a Zorst"

Cross threaded spark plug 170874
    

12Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Fri May 18, 2012 9:55 pm

ReneZ

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The BMW manual is very good (I think) in taking you along the process. If you have a mate who does more wrenching the better! If not, talk to a bike shop and ask for an estimate. We can help you remotely, but you'll need to do the work then!


__________________________________________________
Greetings from Florida Australia! Having a 'new' K     Surprised-o: 

Rene


BMW K100 - 1985 (0030029) Scotland Cross threaded spark plug Rain
BMW K1200GT - 2003 (ZK01223) Florida
BMW K1200GT - 2004 (ZK27240) Australia
    

13Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Sat May 19, 2012 8:57 am

rosskko

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I think I can take that advice. Off to the bike shop I go.
Thanks guys.
rossco

    

14Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Sat May 19, 2012 9:47 am

robmack

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Guest in the House wrote:Stop. Don't do it without help.
+1
Read on another motorcycle forum I follow about a guy who's bike spat a plug at him. Caused a huge welt in his leg that ached for weeks. Apparently, the PO tried putting in a Helicoil to repair damaged spark plug threads and did a botched job of the repair. You don't want the same result for your bike. Seek a pro as GITH suggests.


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1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

15Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Sat May 19, 2012 10:13 am

rosskko

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Booked in with the local bike shop.
Thanks again

rossco

    

16Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Tue May 29, 2012 11:44 am

rosskko

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Case closed.
Mechanic greased up the thread and put a tap in it. Runs in and out like a charm. He said he cleaned it out, but going to blow some air through it to be sure.

Thanks for the advice all.
rossco

    

17Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Tue May 29, 2012 12:44 pm

Two Wheels Better

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rossco wrote:Case closed.
Mechanic said... he cleaned it out, but going to blow some air through it to be sure....
rossco

Ooh, I wonder where that blast of air will direct the tiny bits of aluminium and such? That's a robust combustion chamber but the shards of aluminum that don't immediately get exhausted out upon start-up will be flying about and can make some interesting primitive cave paintings that'll could be there for eternity. I'd just use a bit more clean grease twisted onto a clean rag and carefully wipe it in and out of the 'new' threads until clean and debris-free. It's important to remember that a tap does remove some of the necessary aluminium in order to make those 'new' threads, so be extra careful when turning a new plug in and use the proper torque setting....but not too much...


__________________________________________________
The forest was shrinking, but the trees kept voting for the axe, for the axe was clever, and convinced the trees that because his handle was made of wood, he was one of them. -Turkish proverb
1977 R75/7-100, '93 K11/K12 Big Block, '93 K1100RS, '95 R100 Mystic, '96 K1100RS, 2 x '98 K1200RS, '06 K1200R & '09 K1300GT
    

18Back to top Go down   Cross threaded spark plug Empty Re: Cross threaded spark plug Tue May 29, 2012 2:43 pm

nino

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rossco wrote:Case closed.
Mechanic greased up the thread and put a tap in it. Runs in and out like a charm. He said he cleaned it out, but going to blow some air through it to be sure.

Thanks for the advice all.
rossco



Congrat Rossco. Its easy. Only problem position deep inside.

    

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