franhud Posted February 5, 2010 Share Posted February 5, 2010 hi i have a 03 dt125r and after a days use i have to replace the spark plug could someone please tell me how to solve the problem thanks Link to comment Share on other sites More sharing options...
Moderator Cynic Posted February 5, 2010 Moderator Share Posted February 5, 2010 hi i have a 03 dt125r and after a days use i have to replace the spark plug could someone please tell me how to solve the problem thanks What's the plug look like when its done, black, white, nice coffe tan colour. Red spots on the insulator. Any cracking. Are you SURE its the plug. Have you tried changing the cap as well. Link to comment Share on other sites More sharing options...
franhud Posted February 7, 2010 Author Share Posted February 7, 2010 What's the plug look like when its done, black, white, nice coffe tan colour. Red spots on the insulator. Any cracking. Are you SURE its the plug. Have you tried changing the cap as well. hi its black and its defontly the plug because when i put a new one in its fine im woundering if i need a hotter plug e.g one from a yz Link to comment Share on other sites More sharing options...
Guest MaD.VeZ Posted February 7, 2010 Share Posted February 7, 2010 hi its black and its defontly the plug because when i put a new one in its fine im woundering if i need a hotter plug e.g one from a yz Plug should be a NGK BR9ES(Factory standard) or BR8ES(hotter type), which are you running? When you say black, is it a dry and sooty black(over rich fuel/air mixture), or wet and oily black(excess 2-stroke) ? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted February 7, 2010 Moderator Share Posted February 7, 2010 hi its black and its defontly the plug because when i put a new one in its fine im woundering if i need a hotter plug e.g one from a yz No, something is causing the plug to fail, its a symptom not the cause. An ignition fault can give the impression of a rich mixture due to the incomplete burn as the spark brakes down. Have you tried re fitting the old failed plugs at a later date. And have you tested the plug cap and coil. Fuel won't kill a plug and 2stroke wont either. Something electrical is messing you about. Link to comment Share on other sites More sharing options...
franhud Posted February 7, 2010 Author Share Posted February 7, 2010 hi i was running it on br9es but i have bought a br8es today so im going to give that a try thanks Link to comment Share on other sites More sharing options...
Guest MaD.VeZ Posted February 7, 2010 Share Posted February 7, 2010 No, something is causing the plug to fail, its a symptom not the cause. An ignition fault can give the impression of a rich mixture due to the incomplete burn as the spark brakes down. Have you tried re fitting the old failed plugs at a later date. And have you tested the plug cap and coil. Fuel won't kill a plug and 2stroke wont either. Something electrical is messing you about. ^^You need to answer these really. A hotter plug wont make any difference if its electrical^^ All a hotter plug does is help keep the build up of carbon down on the plug(usually on a poorly tuned or older bike). I was thinking it was just a fouled plug, but without any more info/pics on the plug condition its guess work. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted February 7, 2010 Moderator Share Posted February 7, 2010 BR8 is a hotter plug than BR9 so may help Here's a useful picture Link to comment Share on other sites More sharing options...
franhud Posted February 7, 2010 Author Share Posted February 7, 2010 hi how would i check the cap Link to comment Share on other sites More sharing options...
Moderator Cynic Posted February 7, 2010 Moderator Share Posted February 7, 2010 hi how would i check the cap Standard resistance test, normally 4 Thousand Ohms (4K Ohms) on a resisted cap as a rule but the manual will tell you exactly. While you are looking at the cap, make sure it is securely connected to the lead with a sound electrical connection and the cap locks on to the plug really positively. Link to comment Share on other sites More sharing options...
Guest MaD.VeZ Posted February 8, 2010 Share Posted February 8, 2010 BR8 is a hotter plug than BR9 so may help Here's a useful picture Cool picture, worth keeping a copy Link to comment Share on other sites More sharing options...
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