bdgaf Posted October 28, 2007 Share Posted October 28, 2007 Hi all, I've just discovered this site today while moping about on the web looking for a solution to my electrical problem on my recently resurrected TX500. I hope that some one on the forum will be able to give advice on what the problem is. The story so far: I bought the bike of ebay in a pile of boxes and over the past 18 months I have happily been working away at it. All of the parts have been reconditioned or renewed and the engine has been rebuilt and was running as sweet as it should but one day it started to misfire and ground to a halt. The situation now is, the bike wont go but if I take the plugs out and given a quick rub with a wire brush they spark ok and on putting them back in, the bike will run for only a few seconds then die. When I take the plugs out again they wont spark at all until I clean them again. I've tested and replaced the plugs, the caps, the HT leads, the coils (only resistance test, not spark jump), renewed the points, the condenser, the wiring loom, the rectifier, I've tried the battery from my VFR and still nothing. The points gap and the timing have been set as specified, as have the plug gaps. I should mention that the spark quite weak in that its more of a flash rather than jumping the plug gap and bizarrely it still sparks if the plug isn't earthed on the engine (??). There is also a difference of around 0.8 - 1V between the battery and the power supply to the coils (is this normal?). Also, if I put the meter on one of the points and the +ve terminal on the battery, there is the same difference. Suffice to say I'm completely baffled on the whole thing and any advice would be greatly appreciated. Many thanks, Allan Link to comment Share on other sites More sharing options...
Moderator drewpy Posted October 29, 2007 Moderator Share Posted October 29, 2007 are you charging ok and reg and rectifier within specs? Battery fully charged? have you made sure the earth strap is secure to the engine? my coils checked out ok ohm wise, but heated up so much the wax melted in the HT input (sealed) try a new set of coils (£23 off ebay for pair) Link to comment Share on other sites More sharing options...
yoda Posted October 29, 2007 Share Posted October 29, 2007 If you have a weak spark in open air conditions, it is quite possible that it will not spark under compression. Also if its sparjing without being grounded it must be grounding on the outer of the spark plug lead. For a good spark you need a good earth. Link to comment Share on other sites More sharing options...
bdgaf Posted October 29, 2007 Author Share Posted October 29, 2007 Thanks!! I'm pretty sure the earth is ok but I'm going to head out to the garage just now and check anyway. i'll let you know how it goes ( if it does!!) Thanks again, Allan Link to comment Share on other sites More sharing options...
bdgaf Posted October 29, 2007 Author Share Posted October 29, 2007 Bollocks. still nothing. i'm using some earth wire i got from halfords (its actually a ground lead for an amplifier), its about 3mm dia copper flex - i take that this will be suffice? i tried moving it elsewhere on the engine and also onto the frame. still with no improvement. while faffing about i discovered that if i hold the plug about 5mm from the engine the spark jumps the gap in a nice big spark, this says to me that the coils are ok. would you agree? but when the plug earths on the engine the spark goes back to just a tiny wee flash. I'm pretty sure that since i've tested all the components and they all seem fine that i've done something stupid while building it up. if anyone wants to post the basic checks i can carry out or lead me to a troubleshooting site, i'd be very grateful. i'm no very bright, but i can lift heavy things...... Link to comment Share on other sites More sharing options...
Moderator drewpy Posted October 29, 2007 Moderator Share Posted October 29, 2007 Bollocks. still nothing. i'm using some earth wire i got from halfords (its actually a ground lead for an amplifier), its about 3mm dia copper flex - i take that this will be suffice? i tried moving it elsewhere on the engine and also onto the frame. still with no improvement. while faffing about i discovered that if i hold the plug about 5mm from the engine the spark jumps the gap in a nice big spark, this says to me that the coils are ok. would you agree? but when the plug earths on the engine the spark goes back to just a tiny wee flash. I'm pretty sure that since i've tested all the components and they all seem fine that i've done something stupid while building it up. if anyone wants to post the basic checks i can carry out or lead me to a troubleshooting site, i'd be very grateful. i'm no very bright, but i can lift heavy things...... Im not sure that means the coils are ok as what I think is happening is, the HT primary has a bit longer to build up the power and finally jumps the gap, that is how those gizmos work which are said to improve the sparking. you need 12V to the coils!! try temp routing a lead to them from battery and recheck spark or check fuse box for any resistance. how are your leads connected to the coils? undo and redo the caps (are they resistance type? as you may have resistance leads as well!!) Link to comment Share on other sites More sharing options...
bdgaf Posted October 29, 2007 Author Share Posted October 29, 2007 with the one that's on it i'm getting 12v at the battery and about 11.3v at the coil. not so good so i'm charging the battery just now but i think i'll get new one cos its been a bit abused since i started working on the bike. the ht leads press onto the coil at the end and the a cap screws on. ehh.. what are resistance leads?? i'm away back out to the garage to try the route directly from the battery and probably scratch my head... thanks for your help again. allan Link to comment Share on other sites More sharing options...
bdgaf Posted October 31, 2007 Author Share Posted October 31, 2007 WAHEY!! Problem sorted last night. Turns out i've got a faulty ignition switch ( i knew it would be something stupid - lessen learned!) I bypassed the switch and the bike now goes again like a dream. Thanks for all your help. allan Link to comment Share on other sites More sharing options...
Moderator drewpy Posted October 31, 2007 Moderator Share Posted October 31, 2007 WAHEY!! Problem sorted last night. Turns out i've got a faulty ignition switch ( i knew it would be something stupid - lessen learned!) I bypassed the switch and the bike now goes again like a dream. Thanks for all your help. allan Bloody 'ell eh!! nice one, things like that drive me crazy. just sorted a friends bike (An "aherm!", gilera cougar) extra wiring and lots of tracing and multimetering!! (is that a word?) Link to comment Share on other sites More sharing options...
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