zippy Posted July 5, 2013 Report Share Posted July 5, 2013 Zippy #9 - don't do this - it can wreck your CDI, I will post why when I have more time. Disco - I guess you will try a new plug cap - they usually contain a resistor that can fail. Zippy was being a bit of a twit when he posted about holding the plug and kicking over............................ Quote Link to comment Share on other sites More sharing options...
dadof2 Posted July 5, 2013 Report Share Posted July 5, 2013 Why not to kick the bike over without the plug properly connected and earthed? Even at starting rpm the coil will supply in excess of 7000 volts. If these 7000 volts can't get to the bike earth they can go back through the coil and CDI wrecking the CDIs transistors which work at around 5 volts. Disco - sorry for hijacking your post a little with the following - I was aware you were not happy with a voltmeter when I made my earlier post but usually you can find someone who is. When diagnosing potential ignition failure many years of experience has taught me to start with the basics first. First change the plug for a known good one. If that does not work I go straight to the stator. Being subject to heat and vibration this is where component failure is most likely and resistance out of range is one of the easiest checks to carry out and only needs a multimeter which can cost less than £15. my next check is to spin the engine with a power drill and check the outputs from the source and trigger coils. The trigger coil is hall effect with an analogue output (the digital processing takes place in part of the CDI unit) If these outputs are OK then the next check is the CDI to coil output, coil and HT lead resistance etc. It is well worth the taking the time to learn about ignition systems and what you can do with a multimeter - it will save you time and money. Although I am a qualified motorcycle mechanic I have done quite bit of work on cars where swapping components is not an economic proposition cost or timewise, You have to be able to diagnose based on OBD info or outputs. Cheers Quote Link to comment Share on other sites More sharing options...
copemech Posted July 6, 2013 Report Share Posted July 6, 2013 (edited) Why not to kick the bike over without the plug properly connected and earthed? Even at starting rpm the coil will supply in excess of 7000 volts. If these 7000 volts can't get to the bike earth they can go back through the coil and CDI wrecking the CDIs transistors which work at around 5 volts. Disco - sorry for hijacking your post a little with the following - I was aware you were not happy with a voltmeter when I made my earlier post but usually you can find someone who is. When diagnosing potential ignition failure many years of experience has taught me to start with the basics first. First change the plug for a known good one. If that does not work I go straight to the stator. Being subject to heat and vibration this is where component failure is most likely and resistance out of range is one of the easiest checks to carry out and only needs a multimeter which can cost less than £15. my next check is to spin the engine with a power drill and check the outputs from the source and trigger coils. The trigger coil is hall effect with an analogue output (the digital processing takes place in part of the CDI unit) You Think? Sorry lad, but think again! I am not sharing any more info to you on this issue! If these outputs are OK then the next check is the CDI to coil output, coil and HT lead resistance etc. It is well worth the taking the time to learn about ignition systems and what you can do with a multimeter - it will save you time and money. Although I am a qualified motorcycle mechanic I have done quite bit of work on cars where swapping components is not an economic proposition cost or timewise, You have to be able to diagnose based on OBD info or outputs. Cheers Edited July 6, 2013 by copemech Quote Link to comment Share on other sites More sharing options...
disco1001 Posted July 6, 2013 Author Report Share Posted July 6, 2013 (edited) Update:...Bingo....Back running...Thanks to all postmen...and Zippy for the recent advice...all taken onboard... Cut the split ht back even more...now only about 6cm in length..replaced plug cap for new, one more suitable which just ,makes the plug top.... Binned the 2 spark plugs and replaced with new.... Off she whent running sweet... From what i saw...i believe the issue was too much bend in the ht lead, also split and maybe the plug cap or plugs also contributed... Also ordered new CDI unit...dont like the short length im running with now...will swap...just to make me feel more confident in reliability... All good advice given.....the best one for me...'was work backwards' dont go straight for the CDI / stator....(which i nearly did)....may save you money...and effort Funniest was hold onto the ht lead with your hand.....haha....my 15 year old lad was the one who drew the short straw,,,,,but it worked and hes ok..... Happy Man...again...big thanks to all. Im sure i will be back again... Edited July 6, 2013 by disco1001 Quote Link to comment Share on other sites More sharing options...
b40rt Posted July 6, 2013 Report Share Posted July 6, 2013 You can replace just the HT lead on some coils, worth a look. Quote Link to comment Share on other sites More sharing options...
disco1001 Posted July 6, 2013 Author Report Share Posted July 6, 2013 Looks like its a sealed unit...thanks pal... 1 Quote Link to comment Share on other sites More sharing options...
b40rt Posted July 6, 2013 Report Share Posted July 6, 2013 Seen this ? http://www.trialsbits.co.uk/product_info.php?cPath=80_190&products_id=714 Quote Link to comment Share on other sites More sharing options...
disco1001 Posted July 6, 2013 Author Report Share Posted July 6, 2013 Thanks for the link b40rt... Will get one of these and add it into the one i am removing...then will have a back up if ever needed... Cheers Mate, Quote Link to comment Share on other sites More sharing options...
dadof2 Posted July 6, 2013 Report Share Posted July 6, 2013 Copemech # 18 - your underlined comment, please do share any more info you have. I am aware that a hall effect sensor is not a trigger coil and works differently, it does have square wave output at lower voltage than a magnetic induction "self generating" type trigger but I still would not regard it as digital. The digital term usually refers to the processing method used in the CDI for the advance curve. PS sometimes what i post is true as far i feel the reader needs to know, not the full whole story, in your case different interpretation is probably compounded by me being English and you American. I am guessing you may know quite a bit about these things and therfore when i say I use a 4 channel scope you will know what I have, but although an excellent piece of equipment there is little point in suggesting it as a diagnostic method to most trial bike owners. Cheers Quote Link to comment Share on other sites More sharing options...
copemech Posted July 7, 2013 Report Share Posted July 7, 2013 Update:...Bingo....Back running...Thanks to all postmen...and Zippy for the recent advice...all taken onboard... Cut the split ht back even more...now only about 6cm in length..replaced plug cap for new, one more suitable which just ,makes the plug top.... Binned the 2 spark plugs and replaced with new.... Off she whent running sweet... From what i saw...i believe the issue was too much bend in the ht lead, also split and maybe the plug cap or plugs also contributed... Also ordered new CDI unit...dont like the short length im running with now...will swap...just to make me feel more confident in reliability... All good advice given.....the best one for me...'was work backwards' dont go straight for the CDI / stator....(which i nearly did)....may save you money...and effort Disco, Congrats you got her running! Still makes me wonder what, may never know, you trashed the old plugs you were dealing with, changed the cap. Could well be the cap, would not be the first! Do you have a small prick! If so last I recall it takes about an hour or so to gently pick out an old HT lead out or the CDI unit for replacement, as they are potted in with epoxy or something. There is a small brass pin that sticks up the center of the cable which one must avoid damaging, so it is delicate work but can be done. Funniest was hold onto the ht lead with your hand.....haha....my 15 year old lad was the one who drew the short straw,,,,,but it worked and hes ok..... Happy Man...again...big thanks to all. Im sure i will be back again... Quote Link to comment Share on other sites More sharing options...
copemech Posted July 7, 2013 Report Share Posted July 7, 2013 Copemech # 18 - your underlined comment, please do share any more info you have. I am aware that a hall effect sensor is not a trigger coil and works differently, it does have square wave output at lower voltage than a magnetic induction "self generating" type trigger but I still would not regard it as digital. The digital term usually refers to the processing method used in the CDI for the advance curve. PS sometimes what i post is true as far i feel the reader needs to know, not the full whole story, in your case different interpretation is probably compounded by me being English and you American. I am guessing you may know quite a bit about these things and therfore when i say I use a 4 channel scope you will know what I have, but although an excellent piece of equipment there is little point in suggesting it as a diagnostic method to most trial bike owners. Cheers Send me an email @Verizon.net and I will share something with you, even if I said not! Quote Link to comment Share on other sites More sharing options...
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