Wheezle Posted June 10, 2009 Report Share Posted June 10, 2009 Bike: 2005 Honda Shadow Spirit VT750DCbThe problem I am having is that one side of my head on both cylinders is burning colder and fowling out. On the front cylinder its the left side, while on the rear its the right side. Each cylinder has its own coil to run off of. I pulled and changed the plugs yesterday finding that the ones burning colder were charcoal black and the ones burning right looked as they were supposed to ( tan in the center black around the outside ). This is the 8th or 9th set of plugs in 10,000 miles and I'm confused.Modifications to the Engine are as follows: - Shorty Exaust no baffles- Hypercharger intake w/K&N Filter- Stage 3 Jet kit 134 / 138 are my jet sizesLance Quote Link to comment Share on other sites More sharing options...
ReconRat Posted June 10, 2009 Report Share Posted June 10, 2009 timing?... delay the spark timing a bit?Almost all engine performance modifications require the spark timing to be retarded a little more than stock.But the sooty plugs are on the intake valve side, yes? And dual plug heads?edit: wait, stage 3? your mods need that? Quote Link to comment Share on other sites More sharing options...
Wheezle Posted June 10, 2009 Author Report Share Posted June 10, 2009 Im not sure which side they are on?? Yes I have dual plug heads. The timing is preset and not able to be adjusted without an ignition module and those are like finding a gold bar in the street. Yes I need to have the stage 3 setup unfotunately. I can modify the Ignition pulse generator to advance the timing 4*, but thats all I can do to adjust the timing. Quote Link to comment Share on other sites More sharing options...
ReconRat Posted June 10, 2009 Report Share Posted June 10, 2009 hmmm, Hypercharger mod says it increases flow and velocities...The only thing I can thing of is incomplete combustion.Either too much fuel, or too much fuel on one side of the combustion chamber.But if it's only on one side, the intake or the exhaust, it's probably related to the flow through the head. Something changed the flow and/or mix, or changed the requirements.A quick fix might be to try changing the heat range of the sooty plugs to a hotter one.So you'd have two different heat ranges for plugs, in each cylinder head. Quote Link to comment Share on other sites More sharing options...
Wheezle Posted June 10, 2009 Author Report Share Posted June 10, 2009 Ill try that, What plug would you recommend that I use? I use NGK's now. Quote Link to comment Share on other sites More sharing options...
ReconRat Posted June 10, 2009 Report Share Posted June 10, 2009 (edited) NGK is good, just a different heat range if one is available for the type you are using.The reason, is that cold plugs get sooty, so I'm guessing the sooty plug might be better off if it's hotter.edit: just one level heat range change is plenty, not one that is way different. Edited June 10, 2009 by ReconRat Quote Link to comment Share on other sites More sharing options...
Wheezle Posted June 10, 2009 Author Report Share Posted June 10, 2009 This is gonna sound stupid, but How do you tell the diff? Quote Link to comment Share on other sites More sharing options...
ReconRat Posted June 10, 2009 Report Share Posted June 10, 2009 (edited) The number on the plug. For NGK, if a 9 is normal, an 8 is hotter, and a 10 is colder.A hotter plug has a similar effect to advancing the timing. Combustion temperature will go up 10-20. Watch out for pre-ignition detonation, if you hear or feel it, forget about using a hotter plug.You use a DPR7EA-9?... oops, not sure you'll find a DPR6EA-9. looking...edit, they make them:"NGK Resistor Spark Plug DPR6EA-9. Will also fit Models: Honda VT 750 C 2004-2007"I wonder what happens if you change all four plugs... Edited June 10, 2009 by ReconRat Quote Link to comment Share on other sites More sharing options...
Wheezle Posted June 10, 2009 Author Report Share Posted June 10, 2009 DPR7EA9 is what i am using Quote Link to comment Share on other sites More sharing options...
ReconRat Posted June 10, 2009 Report Share Posted June 10, 2009 I still think it might be just a bit rich in fuel delivery. Sounds like it's close to what it should be. Not far off. It's better a bit rich, than a bit lean. Are the plugs sooty like that after a hard high rpm run? Or is it just sooty from idling about town? Quote Link to comment Share on other sites More sharing options...
Wheezle Posted June 10, 2009 Author Report Share Posted June 10, 2009 I have not done any long rides, so just around town. I ride it like I stole it though all the time. Quote Link to comment Share on other sites More sharing options...
ReconRat Posted June 10, 2009 Report Share Posted June 10, 2009 Ok, me passing out now, I might see you on Friday night up in Hillard. Or Thursday at the Buffalo Wings out East. Quote Link to comment Share on other sites More sharing options...
Wheezle Posted June 10, 2009 Author Report Share Posted June 10, 2009 Ill see u Fri Quote Link to comment Share on other sites More sharing options...
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