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| Exhaust Backfire https://vintagedirtbikeforums.alp-sys.com/viewtopic.php?f=28&t=1244 |
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| Author: | jrenoe [ Sun Nov 12, 2006 3:38 pm ] |
| Post subject: | Exhaust Backfire |
PLease help... I have a 78 Yamaha YZ 400 that will not start and backfires through the exhaust after a half dozen kicks or so. I have tried 2 different CDI boxes and checked that the magneto sheer pin was not broke. Does anyone have any ideas? BTW the spark at the plug looks good. Thanks |
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| Author: | Nathan [ Tue Nov 14, 2006 12:00 pm ] |
| Post subject: | |
I'm fishing on this, but have you checked the intake between the carb and the cylinder for an air leak? A lot of times the old rubber cracks and lets air in. I've had that problem before. |
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| Author: | jrenoe [ Wed Nov 15, 2006 8:52 am ] |
| Post subject: | |
Yes, the rubber appears to be in fair shape. |
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| Author: | behindbars [ Wed Nov 15, 2006 9:01 am ] |
| Post subject: | |
How are the reeds? Have you checked your compression? Certainly could be an air leak as well. |
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| Author: | jrenoe [ Wed Nov 15, 2006 9:48 am ] |
| Post subject: | |
Compression is great... Reeds I have not checked |
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| Author: | expat [ Fri Nov 17, 2006 12:29 pm ] |
| Post subject: | |
Was this bike a runner that became sick or a rebuild that will not run?? |
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