my new xs400

murph · Posted: January 24, 2009, 11:44 pm Post subject: my new xs400

I feel like I've been away from this site for a long time.. almost a year. I'm glad to see so many more members Smile

I'm also looking forward for the spring and to start ridding daily.

Well, I just bought a 79 xs400 for my girlfriend the bike has only 2,760 miles on it and is in great condition, but the previous owner decided to cross thread in the left spark plug. I can't figure out why you wouldn't stop when the plug wouldn't just spin on but that's another story... I've been able to get it out but can't get a new one in there. I've tried for the last hour to set a new plug by going 1/16th of turn.. then off then + another 1/16th and repeat. It has been working but seems to be building up quite a bit of material on the the threads. does anyone have any ideas?

jayel · Posted: January 25, 2009, 12:05 am Post subject: Re: my new xs400

chase it with a greased tap not a spark plug, even after that you may need to heli-coil it or a insert, once those threads are boogered up I wouldn't trust them

kzxs · Full Member Joined: May 08, 2008 Posts: 22 Location: OKC

You have to be careful not to get any shavings in the motor, but I agree with tapping and helicoiling. We use an air powered vacuum to suck the shavings out of the cylinder.

murph · Posted: January 26, 2009, 1:54 am Post subject: Re: my new xs400

What size tap should I use? I used a 13/16" socket to get the plug out.

murph · Posted: January 26, 2009, 2:19 am Post subject: Re: my new xs400

would this work? www.amazon.com/Tools-3...75&sr=8-11

kzxs · Full Member Joined: May 08, 2008 Posts: 22 Location: OKC

It might, you would have to be careful not to make the threads worse. As longs as the thread is the same size and pitch, the tap should work. I would make sure that t it sealed completely with the plug in. If the threads are bad then it may become stripped out and then it would be hard to remove and may cause a loss in compression (I think...) I would use something like Helicoil Spark Plug Thread Repair Kit Make sure to get the shavings out.
aybe an aluminium magnet! Laughing

Seriously..Good luck

murph · Posted: January 26, 2009, 9:41 pm Post subject: Re: my new xs400

I found this one on amazon [url=http://www.amazon.com/Helicoil-5334-14-Thread-Thread-Repair/dp/B0002SRF4O/ref=sr_1_2?ie=UTF8&qid=1233015923&sr=8-2 ]helicoil amazon[/url]

Thanks for the help. I hope the shopvac will be able to get the shavings out. Very Happy

I'll put some pics up of my progress.

jayel · Posted: January 26, 2009, 9:42 pm Post subject: Re: my new xs400

just set your engine so the exhaust valve is open on that side when you retap the plug hole, then you can use compressed air to blow out any chips, however if you grease the tap that will get almost all of the chips, the only thing wrong with not heli-coiling the head is the threads are going to be weaker from the removed material just be careful cranking your plug in don't over-tighten them, I've seen plugs blow right out of a head before from worn/stripped threads

murph · Posted: January 26, 2009, 9:43 pm Post subject: Re: my new xs400

that's a great idea about the open exhaust. And I'll definitely be using grease.

Retiredgentleman · Posted: January 26, 2009, 11:06 pm Post subject: Re: my new xs400

jayel's idea to have the exhaust valve open should be a good way to go. If you had a shop vacuum, you could attach the vacuum hose to the exhaust pipe and plug the other exhaust to prevent pulling through the cross-over pipe.

batman911 · Posted: January 27, 2009, 12:10 am Post subject: Re: my new xs400

These are all real good bits of advice... Make sure once you get your threads repaired that you use anti-seize on the threads of the spark plug before you put it in.

murph · Posted: January 27, 2009, 4:08 am Post subject: Re: my new xs400

I take care of my bikes, they get anti-seize; I just wish I had pulled the plugs before I bought the bike. Mad

I'm going to order the Heli-coil kit tomorrow.

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