Toutsuite Posted September 23, 2014 Share Posted September 23, 2014 Changed my plugs today on the Dragstar 650. Here are the old ones, they've been on about a year, about 4-5k miles: rear cylinder: front cylinder: Any of you chaps can give us a reading? Too lean/rich, hot/cold, just right, or not? Anything else? Edit: these pics show the darker side (oooh, Darth!). They are a much lighter tan on t' other side. Link to comment Share on other sites More sharing options...
gizmo666 Posted September 23, 2014 Share Posted September 23, 2014 i would say they both look good engine running ok but hey i'm no mechanic Link to comment Share on other sites More sharing options...
Preload Posted September 24, 2014 Share Posted September 24, 2014 They look a tad fat and wet to me but not familiar with this engine, were they taken out after a good run or not? is the air filter clean? but saying that If its running okay and the mpg is right leave well alone. Link to comment Share on other sites More sharing options...
Toutsuite Posted September 24, 2014 Author Share Posted September 24, 2014 They were taken off a cold engine, she had a good run on Sunday, two days previously. The threads are oily because they still had copper grease on them. The ends are dry. Link to comment Share on other sites More sharing options...
Preload Posted September 24, 2014 Share Posted September 24, 2014 Hmm..If the motor hasn't been started at all since the good run, I would aspect them to be a light biscuit colour all around the porcelain. Since its an air cooled motor Yamaha do tend to set the carbs a bit on the rich side. Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted September 24, 2014 Moderator Share Posted September 24, 2014 Got to agree with Preload, a little dark but don't look too bad. That gap looks quite big though - that said I don't know what the gap size should be. Link to comment Share on other sites More sharing options...
Noise Posted September 24, 2014 Share Posted September 24, 2014 Yer they look ok to me, a little rich but nothing too stupid. Again without having the book infront of me i couldn't tell you the gap either but probably worth a check if you can. Atleast you still got plenty of meat on the electrode Link to comment Share on other sites More sharing options...
Toutsuite Posted September 24, 2014 Author Share Posted September 24, 2014 Gap's fine, 0.8 to 0.9mm Noise in your experience with draggie sp's, are they darker on one side than the other? Link to comment Share on other sites More sharing options...
neversaydie Posted September 24, 2014 Share Posted September 24, 2014 They look fine to me, slightly more pitting on the front one, colour looks good, no carbon, not oily. I'd stick them back in, check again in 3 months Link to comment Share on other sites More sharing options...
Noise Posted September 25, 2014 Share Posted September 25, 2014 How do you mean darker on one side? Do you mean rear cylinder is darker than the front or one side of the spark plug is darker than the other side? When i changed mine they where near on the same only mine where a tad on the whiter side so i need to buy bigger jets (but thats a side track moment) i am only guessing here so don't quote me, i would think that if one side of the spark plug is darker it maybe because of the way its sat in the cylinder and how it lines up with the valves. If one side is next to the inlet valve its getting hit by a mix of air and fuel so when it burns it will leave a certain amount of soot one that side of the plug, whereas the other side is closest to the exhaust valve and will just be clearing out the chamber. Again thats only a guess as the inlet valve should spray and coat the whole chamber with fuel/air mix thus coat the whole spark plug. But again before its all compressed its going to spray the plugs first. Hope that made sense as im on my mobile with fat finger syndrome haha Link to comment Share on other sites More sharing options...
Toutsuite Posted September 25, 2014 Author Share Posted September 25, 2014 Yeah noise, that makes sense. I meant darker on one side of the plug. They are about the same from one cylinder to the other. Link to comment Share on other sites More sharing options...
Toutsuite Posted September 25, 2014 Author Share Posted September 25, 2014 Think I might try a k&n filter since the plugs appear to be a smidge on the rich side. See what that does... 1 Link to comment Share on other sites More sharing options...
Noise Posted September 26, 2014 Share Posted September 26, 2014 Yer that will help but to be fair if she is running ok and isn't spluttering up the road under acceleration then she will be fine. But if your coming up to a service you may as well chuck a K&N on her. Link to comment Share on other sites More sharing options...
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