Plug thread size different on same engine
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Stage IV
Joined: Jun 2015
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From: Ohio
Plug thread size different on same engine
I have a 2003 1200 custom sportster. When I started to check spark plugs I found one plug was a larger thread and the plugs were different. I'm new to Harley's but I'm almost positive this isn't the way it should be. Has anybody seen this before? If so what can be done to correct this problem besides buying a new head?
Outstanding HDF Member
Joined: Apr 2012
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From: North Florida
I have a 2003 1200 custom sportster. When I started to check spark plugs I found one plug was a larger thread and the plugs were different. I'm new to Harley's but I'm almost positive this isn't the way it should be. Has anybody seen this before? If so what can be done to correct this problem besides buying a new head?
There are tread repair inserts like helicoil and time sert, or you could have the head welded and re cut, or strip the other and drill it larger.
That Or ride it, that would not bother me at all.
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Stage IV
Joined: Jun 2015
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From: Ohio
Thanks what would be the two plug numbers u would use?
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Stage IV
Joined: Jun 2015
Posts: 4
Likes: 0
From: Ohio
Thanks what two numbers would u use for the new plugs?
Road Master
Joined: Apr 2012
Posts: 1,096
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From: San Jose
Not knowing what size your cyl head has been oversized to, I would find the correct insert to reduce the thread back to factory size, 12mm I believe.
The kits can get expensive. so for a one time job you might seek out a local shop that could do the repair. Might be cheaper in the long run.
This is a sample of the repair kits
http://www.timesert.com/html/sparkplug.html
The kits can get expensive. so for a one time job you might seek out a local shop that could do the repair. Might be cheaper in the long run.
This is a sample of the repair kits
http://www.timesert.com/html/sparkplug.html
Outstanding HDF Member
Joined: Apr 2012
Posts: 2,938
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From: North Florida
Stock plugs are champion, I would find a supplier that sold them and ask them to get the same heat range resistance etc, in the different thread size.
Stock is RA8HC.
What is in there now?
Stock is RA8HC.
What is in there now?
Last edited by Harleycruiser; Jun 11, 2015 at 08:52 PM.
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Banned
Joined: Sep 2009
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From: deland,florida
if it bothers you,just go 14mm on the other head.no way ide start welding up the 14mm head to go back to 12mm.ive done that for twin cam guys with stripped heads,just machine to 14mm,no biggie
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