warkilt Posted May 9, 2009 Share Posted May 9, 2009 Hey I just bought a 79 xs 400, the person I bought it from said it needed the carbs clean so I did that. When I tried to start it the fuses got really hot and then burned out. I figured that they might be bad so I replaced them tried to start it again and then they start to smoke and burned out. Does anyone know what might be the problem? A friend told me to pull the harness and check for corrosion. If anyone could help it would be greatly appreciated Thanks Link to comment Share on other sites More sharing options...
JimR Posted May 9, 2009 Share Posted May 9, 2009 Hey I just bought a 79 xs 400, the person I bought it from said it needed the carbs clean so I did that. When I tried to start it the fuses got really hot and then burned out. I figured that they might be bad so I replaced them tried to start it again and then they start to smoke and burned out. Does anyone know what might be the problem? A friend told me to pull the harness and check for corrosion. If anyone could help it would be greatly appreciated Thanks Hi Warkilt, is this an instant fuse blow or only when the starter motor is engaged ? If when the button is pressed does the motor turn over or is it at this point the fuse blows? If the fuse blows at this point I would guess a fault with the starter motor but we need some more info Regards Jim Link to comment Share on other sites More sharing options...
warkilt Posted May 9, 2009 Author Share Posted May 9, 2009 Hey yeah it it does turn over but just as it is about to start the fuse blows. Thanks Connor Link to comment Share on other sites More sharing options...
JimR Posted May 9, 2009 Share Posted May 9, 2009 Hey yeah it it does turn over but just as it is about to start the fuse blows. Thanks Connor Hi Connor, which fuse ? Regards Jim Link to comment Share on other sites More sharing options...
warkilt Posted May 10, 2009 Author Share Posted May 10, 2009 Ah i am not sure but i think it is the main electrical fuse that is blowing. Thanks Connor Link to comment Share on other sites More sharing options...
JimR Posted May 11, 2009 Share Posted May 11, 2009 Ah i am not sure but i think it is the main electrical fuse that is blowing. Thanks Connor Hi Connor, The fuse box contains a few fuses so I guess the one you have blowing is the 'main' fuse ? First test is to bridge (short hot, I think the US term is) the starter switch (no need to have the ignition switched on) to turn the motor over if the wirring gets hot & the fuse blows there is a chance you have a problem with the starter motor, BTW another test would be to get the old kick start out & see if it starts ok from there. I'm trying to get my head around that you know the bike is just about to start, are you getting a fire then the fuse blowing ? At what speed does the starter turn at ? does it sound like the engine is being turned at 3 or 4 rpm or 50 rpm ? Regards Jim Link to comment Share on other sites More sharing options...
warkilt Posted May 12, 2009 Author Share Posted May 12, 2009 Hi Connor, The fuse box contains a few fuses so I guess the one you have blowing is the 'main' fuse ? First test is to bridge (short hot, I think the US term is) the starter switch (no need to have the ignition switched on) to turn the motor over if the wirring gets hot & the fuse blows there is a chance you have a problem with the starter motor, BTW another test would be to get the old kick start out & see if it starts ok from there. I'm trying to get my head around that you know the bike is just about to start, are you getting a fire then the fuse blowing ? At what speed does the starter turn at ? does it sound like the engine is being turned at 3 or 4 rpm or 50 rpm ? Regards Jim Ah it sounds like probably around 3 or 4 rpm when it is about to start. I also was going to just use the kick start but it didn't even remotely turn over when i tired it but maybe i am not kicking fast enough. also i did find a few shorts in the wiring harness so maybe when i fix those the problem will be solved thanks again Connor Link to comment Share on other sites More sharing options...
JimR Posted May 12, 2009 Share Posted May 12, 2009 Ah it sounds like probably around 3 or 4 rpm when it is about to start. I also was going to just use the kick start but it didn't even remotely turn over when i tired it but maybe i am not kicking fast enough. also i did find a few shorts in the wiring harness so maybe when i fix those the problem will be solved thanks again Connor Hi Connor How do you know its about to start ? Regards Jim Link to comment Share on other sites More sharing options...
warkilt Posted May 12, 2009 Author Share Posted May 12, 2009 Hi Connor How do you know its about to start ? Regards Jim Ah I guess because it starts to rumble but i am kind of new to this so maybe it isn't about to start at all. Link to comment Share on other sites More sharing options...
JimR Posted May 13, 2009 Share Posted May 13, 2009 Ah I guess because it starts to rumble but i am kind of new to this so maybe it isn't about to start at all. Hi, I would guess that to be the starter motor getting a bit hot ! & not the bike about to start. I still think you should do some basic checks to the engine & try and start it from the kick start. Statically check the ignition timming & point gap Check valve clearences if the bike is a non runner, remove the carbs ,strip & clean them, clean the fuel tank & tap out Check the plugs Check that you have a nice blue spark at the plugs. When you try to start the engine set the fuel tap to the PRI position and use the kick start. If the bike then starts and the fuse doesnt blow you have narrowed it down to a starter motor and/or starter relay Regards Jim Link to comment Share on other sites More sharing options...
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