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Discussion Starter · #1 ·
Today I started er up and it backfired, then started running on only one cylinder. It has been running like a top for the past 2200 miles(it had about 7200 on it when I got it). Is this likely a plug issue, and is it the first thing you would check? Also, the majority of my riding is under 50 mph...would you recommend going to a hotter plug? The manual does say you should use a hotter plug if you do a lot of low speed or cold weather riding. I take it that <50 mph qualifies as low speed riding.
 

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Discussion Starter · #3 ·
OK Knightslugger, thanks for the tip. I'll start digging into it tomorrow to see what's wrong. As I said in my first post the bike has run without a hiccup for 2200 miles and now has only about 9400 miles on it( it had ~ 7200 when I got it ). Would one expect to have a plug issue after only 9400 miles?
 

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depends. did you change something with the intake/exhaust recently? does it have anything non stock? It might NOT be plug related you know. Just Ignition issues. could be a bad coil, or a disconnected wire, loose connection... If you're NOT getting spark, check your connections starting at the plug.
 

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oh if you dont know how to do it, pulling the plugs can be a tough thing the first time around on this bike. I pull the crankcase breather piece off to give the socket and extension more clearance. while you've got the breather off, its also a great opportunity to look at it, and clean it.
 

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Discussion Starter · #6 ·
You are correct that changing the plugs is less than easy. To make a long story short, when I got in there this afternoon, one of the plugs had vibrated completely out of its socket...wow. Of course I did not have an appropriate metric spark plug wrench, so ran around finding one, then put in a new plug. Still need to change the other, but think it's obvious what the problem was, so anticipate no problems when I fire it up tomorrow. Will let you know what final outcome is.
 

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Discussion Starter · #7 ·
As the final chapter to my previous post(hopefully), I got the other plug put in, put the tank back on, etc. and fired her up a few minutes ago...runs fine. How unbelievable that the one plug vibrated loose at the end of my previous ride, where I had been out in the countryside...never had any hint that there was an issue until I tried to start it for my next ride(several days ago). All problems with motorcycles should be so accomodating to occur when you're at home like that, rather than out in the boondocks.
 

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Check your plug torque again after the engine has heated up and cooled off a few times. Especially with a new plug. The different expansion rates of the metal in the cyl. head and the plug can cause them to back out. Especially these small plugs that are low torque. Another reason to check it is in case the loose plug has wrecked the threads in the head.

I had this happen to me in an AIRPLANE. Talk about being damn inconvient. Two plugs per cylinder though so the engine still ran - badly.
 

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Discussion Starter · #9 ·
Thanks for the tip Mad Matt. I never would have dreamed that a plug could vibrate out like that...back in the 60s and 70s when I was still doing some of my own car service, like plugs, etc. I never saw such a thing. I've been on several rides since changing them and it seems smooth as silk(or a Ninja I should say). By the way, what kind of torque are they supposed to have?
 

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Those cars probably had steel heads and 14mm + plugs. I don't have the owner's manual in front of me (should be in there) but on a 10mm plug the torque is typically 108 to 120 inch pounds. In other words not much. So shoot for 114 and use a decent torque wrench. I've seen these overtightened so that they deform the head threads and gradually loosen up or just pop out near the end of the compression stroke.
 

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Discussion Starter · #11 ·
OK - I dug out the owners manual it specifies 10 ft-lbs on the plugs, which means you were right in the ballpark with your inch-lb estimate. Thanks again.
 

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Does our bike come with, or would it benefit from installing platinum plugs?
 

· Fast Old Guy
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Sorry, The benifits part.
The EX sparky system is about a strong as My FlickyBicy lighter and needs all the help it can get. The platnium electrodes run hotter and can threrfore burn off the deposits and stay cleaner longer, secondly the edges stay sharper or the full radius on a worn electrode is still sharper then a used standard plug . this enables the spark to jump to the groung easier.
I wrote a thing about Sparks and such I gues I'll have to re-post it here.

FOG
 

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FOG said:
Sorry, The benifits part.
The EX sparky system is about a strong as My FlickyBicy lighter and needs all the help it can get. The platnium electrodes run hotter and can threrfore burn off the deposits and stay cleaner longer, secondly the edges stay sharper or the full radius on a worn electrode is still sharper then a used standard plug . this enables the spark to jump to the groung easier.
I wrote a thing about Sparks and such I gues I'll have to re-post it here.

FOG
No need I can find it when I need it (I hope you were meaning that you posted that spark deal here already on ex-500.com and not that it got lost with ex500riders.org) I was just wondering...
 

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staying more or less on topic, do we need a specific plug wrench to get em out of their sockets?a friend and i were trying to get them out to inspect them this weekend, but to no avail, can someone gimme a link to where i can buy one, it shouldnt be too expensive, right?
 
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