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| 1975 MT 250 illing spark plugs? https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=21&t=1948 |
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| Author: | DJForresta [ Sun Jul 20, 2008 1:45 am ] |
| Post subject: | 1975 MT 250 illing spark plugs? |
This bike is running great but is killing spark plugs like crazy. My only last issue is spark plugs. I'm going through them like candy. They are shorting out. They are not fouling but literally shorting out. Bike starts great and runs fine and then will just die. Pull the plug and replace it and it starts up again then will die. The plugs will arc from the plug to the case but not in the gap after that. Nice blue spark but nothing in the gap it just shorts straight to the outside of the plug. Any ideas what could be shorting out the plugs? I don't have a battery does that matter. I've been running it without a battery. |
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| Author: | Dave [ Fri Jul 25, 2008 9:20 pm ] |
| Post subject: | Re: 1975 MT 250 illing spark plugs? |
the battery on the MT will not affect the Ignition system.do you have a good strong blue spark with a new plug? are you running the engine long enough for it to warm up fully?i would also check the carb and oil pump (if it has one) settings. |
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| Author: | t20sl [ Tue Jul 29, 2008 5:25 pm ] |
| Post subject: | Re: 1975 MT 250 illing spark plugs? |
You ARE describing exactly what a fouled plug shows up like. Arcs inside plug or just jumps across way up inside where you won't see it. The wet fuel carries the current. Your too rich if it is doing that quickly. Are you running the injector? What oil? What plug? Slow speed putting around or riding it hard? When you pull a fouled plug away from head there will be a spark from plug to head. Spark has to try to go to ground. |
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| Author: | DJForresta [ Tue Jul 29, 2008 7:30 pm ] |
| Post subject: | Re: 1975 MT 250 illing spark plugs? |
I'm running about a 32:1 mix. I've been running without an air cleaner because It just came in. I wasn't sure how the air screw worked so that sounds about right. I switched from #9 plugs to #8 and they aren't fouling. Just got a Uni 4 inch filter and oiled it up and its way rich now. When I run out of gas and it leans out this thing runs like a beast for a few seconds before it dies. So hopefully when I get the air screw in I can dial this in. Any advice on screw adjustment would be outstanding. Thanks for all the help so far. |
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