Newbie here! stripped spark plug threads!!

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member9724

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This is my first post ever on this place so bear with me. I recently got an xs400 (guy said it was a 650 but the engine said it was a 391cc) main problem I have with this bike is that the left spark plug thread is stripped!
I've been told to use a helicoil or just go ahead and buy a new head but I have no idea what model bike I have other than the size.
I need suggestions on what to do. Should I go ahead and buy a new head or re thread it? Also how do I find out what model I have?

The Vin is 2L0109138

I appreciate any help I can get and hope to be active on these forums!
 
Helicoil (there are other options, that's a brand name) is a good option. Personally, I would not buy a new head just for this.

That VIN tells me it's an XS400 made before 1981 (otherwise it would have a 17 digit VIN). Probably 1978 or 1979.
 
OK now I'm getting somewhere! So now I know the model year! The guy at the shop I went to was reluctant to do a helicoil and told me to get a new head but his main area of work was sport bikes.
I'll post some pics once I get off work so you can see if it's too far gone.

I really appreciate the help!
 
Looks like I'll be getting it done by a shop! I've never had luck with threading things. All I gotta do now is find a decent shop in Fort Worth to do it!! :D
 
I have been this situation before, if you search my post history you will find the thread i made which solves the issue.

Long story short : I went to Parts Source and bought the 15$ re-threading kit (It wasn't Helicoil, just the house brand).

Just follow its instructions haha I believer it was just grease up the tap, line it up and crank it in until it rethreads the spark plug hole. After this you would then secure the threaded sleeve to effectively shrink it back to the original size to fit your spark plug.

In my case i had only cross threaded the first couple threads so after a couple turns on the the tap my spark plug was able to just skip those and screw int the rest of original threads. I didn't need to use the sleeves. Every was good after that.

It cost 15$ and took about 30 minutes (i was going very slowly lol)
 
Use plenty of grease on the tool. back it out after a few turns to see how many chips build up in the grease. Clean off chips and grease, apply more grease go a bit farther. Back out the tool. You will learn just how far you can go between removals to clean off the chips as you go. Better to stop and clean more than not enough. Any way the grease catches the chips so you can back out the tool and clean them off.
I have such a kit I got online. It came with the tool that threads into the old hole and as you go it reams out the hole and threads it for the insert.
The kit came with 4 inserts. All 14 mm threads but different lengths. 3/8's, 7/16's, 1/2 and 3/4's inch. Use the length that matches the plug length.
Leo
 
Wow im surprised at how helpful this community is! But here go the pics as promised! As soon as I got home i got to tearing it down!

20140426_092445.jpg

20140427_173215.jpg

20140428_161218.jpg

Ill post some more once i find the pics on my phone!
 
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I was somewhat disappointed since the frame work was already done. That's probably my favorite part of building a bike is the welding and cussing when you can't get it even. All I can do to it is clean the welds (some are rusting) and relocate that brake and get rid of that hugeass caliber on the rear
 
Are you going to fit a smaller caliper or try to find a drum brake/wheel for it.
 

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