DE51GNZ Posted March 27, 2011 Posted March 27, 2011 Hi guys, Well i have the bike running but i have noticed it is only firing on 1 cylinder. Done a few checks and both coils are good, tested continuity from CDI unit wires in harness and all ok. Bike has new regulator and is charging ok, put new Iridium spark plugs in. Question i would like to ask is: is it possibly a stator fault or am i looking at a replacement CDI? Any help would be greatly appreciated. I have also noticed i get no neutral light when ignition on. I have done a continuity check on the switch and it is open, so i think it maybe broken. Are they easy to get hold and and change? I am slowly working through the XV 250 service manual as i have been unable to find one for the XV 125 but it is helping alot. It helped me work out that the clutch switch was faulty and once it had a good clean with WD-40 it was working a treat! I turn to you, the knowledgable ones for guidance and advice. Regards Dan
Kelum Posted March 28, 2011 Posted March 28, 2011 Are you sure that the carb offering gas to the particular cylinder? Take out the spark plug and keep it closer to engine frame, then start the bike to see if it makes sparks...that is what mechanics here do in order to see if the plugs getting power..if sparking ok then there would be a gas issue..I had same thing in my early Honda CD 125T benly twin..and hey also check if the plug is getting splashed by engine oil..if sparking ok no need to worry about the CDI unit or wires I guess..check carb..hope this helps and Paul and Ray may further help..
Kelum Posted March 28, 2011 Posted March 28, 2011 Also check if the battery is charging enough..fuses doing fine?
DE51GNZ Posted March 28, 2011 Author Posted March 28, 2011 Also check if the battery is charging enough..fuses doing fine? The main fuse is new as i just renewed the fuse and holder as the other looked slightly burnt. Regulator is new and seems to be recharging the battery ok. I will check the sparks tonight and let you know. Thanks Daniel
Paulwhite Posted March 28, 2011 Posted March 28, 2011 yeah id agree with kelum on this one check that the plugs are sparking. then put ur thumb over the spark plug hole (to seal it) then push the start switch...your thumb should be pushed off and air should escape through the hole. the idea is to check compression you should be able to push against it as hard as you can but air will still push ur thumb and escape. if you find that there is little to no pressure then im afraid its ur piston ring. but hopefully it will be fine
DE51GNZ Posted March 28, 2011 Author Posted March 28, 2011 yeah id agree with kelum on this one check that the plugs are sparking. then put ur thumb over the spark plug hole (to seal it) then push the start switch...your thumb should be pushed off and air should escape through the hole. the idea is to check compression you should be able to push against it as hard as you can but air will still push ur thumb and escape. if you find that there is little to no pressure then im afraid its ur piston ring. but hopefully it will be fine Hi, Went to do the main compression test on the cyclinder and spark plug tests but the main power cable from the battery has snapped!!!! Connection to batter has sheared right off!! Got a new one on order, I will do the checks at the weekend and let you know. Thanks again guys Daniel
Kelum Posted March 29, 2011 Posted March 29, 2011 Hm...guess u've located the issue...piston rings for this model are available on ebay..I saw several on offer...keep them checked also as it will be advisable...
DE51GNZ Posted March 29, 2011 Author Posted March 29, 2011 Hm...guess u've located the issue...piston rings for this model are available on ebay..I saw several on offer...keep them checked also as it will be advisable... Hi guys, I have checked the compression on the cyclinder and it is all ok. I tried your trick paul and it nearly blew my thumb off!! I checked the spark with a tester and NO SPARK. I thought i had better check that it wasnt the coil, so i swapped the orange and grey wires around and then it sparked. So both coils are good. It seems to be the signal from the CDI unit. The grey and orange wires come from the CDI unit. Continuity all good from CDI connector to coil. So back to point 1... Does anyone think it could be the CDI unit? Is there a way of testing that it is sending a signal with a multimeter? Could it be the pickups on the stator windings not sending the signal to the CDI? Any ideas on what to try next?
Paulwhite Posted March 29, 2011 Posted March 29, 2011 i dont know how to check with a voltmeter im afraid all i know is to hook it up to the coil and do a visual check on the plug. you could try hooking the volt meter up to the good side and see what sort of readings you get then use that as a basic for the broken side. what i do know is that its not the actual stator that sends the signal its a pulse coil which is located in the left side engine casing... if you can find the plug that connects engine to loom there will be 3 wires(all the same colour either white or yellow normally) there the ones from the stator, then on the same plug should be a red and a black (or earth) then you should be able to see another set of wires (not sure on colour but should be 2 of them) there the pulse coil wires that send the signal to the cdi i can send you a xvs 125 dragstar manual via e-mail both the virago and the dragstar use the same engine (with minor alterations) which might be helpfull but if one side isnt firing and the coil is ok id check that you havent got a broken wire somewhere in the loom. or a loose connector. the cdi is a sealed unit and there is no way of checking it im afraid other than to "borrow" a working one to swap and try. to be honest i think that will be the simplest idea, then if the "borrowed" cdi dont work you know its the connection from cdi to coil.
DE51GNZ Posted April 4, 2011 Author Posted April 4, 2011 i dont know how to check with a voltmeter im afraid all i know is to hook it up to the coil and do a visual check on the plug. you could try hooking the volt meter up to the good side and see what sort of readings you get then use that as a basic for the broken side. what i do know is that its not the actual stator that sends the signal its a pulse coil which is located in the left side engine casing... if you can find the plug that connects engine to loom there will be 3 wires(all the same colour either white or yellow normally) there the ones from the stator, then on the same plug should be a red and a black (or earth) then you should be able to see another set of wires (not sure on colour but should be 2 of them) there the pulse coil wires that send the signal to the cdi i can send you a xvs 125 dragstar manual via e-mail both the virago and the dragstar use the same engine (with minor alterations) which might be helpfull but if one side isnt firing and the coil is ok id check that you havent got a broken wire somewhere in the loom. or a loose connector. the cdi is a sealed unit and there is no way of checking it im afraid other than to "borrow" a working one to swap and try. to be honest i think that will be the simplest idea, then if the "borrowed" cdi dont work you know its the connection from cdi to coil. Hi Guys, Update on the bike. Checked the primary coil and cleaned it but the bike was still firing on one cylinder. It was the CDI unit that was faulty, not sending a singal on the grey wire. Opened the CDI unit up and did some checks, turns out one of the Avalanche diodes had died. Ordered a new diode from littlediode.com for £6.99, soldered in an now the bike has sprung into life!!!!!!!! So CDI fixed and bike running sweet!!!! Thanks for all your help.
Paulwhite Posted April 4, 2011 Posted April 4, 2011 nice one m8 guess i was wrong about the cdi but good to know you have sorted it
Kelum Posted April 4, 2011 Posted April 4, 2011 Hi Guys, Update on the bike. Checked the primary coil and cleaned it but the bike was still firing on one cylinder. It was the CDI unit that was faulty, not sending a singal on the grey wire. Opened the CDI unit up and did some checks, turns out one of the Avalanche diodes had died. Ordered a new diode from littlediode.com for £6.99, soldered in an now the bike has sprung into life!!!!!!!! So CDI fixed and bike running sweet!!!! Thanks for all your help. Bro please it would be helpful for me as well as the community if you could graphically show where was the fault and how u fixed it, I mean detecting the faulty diode, how u opened the CDI unit...etc..I hope u could open it up once again for us..that sort of issue can come up for any of us XV125 users so please share it in detail.. Thanx..
DE51GNZ Posted April 5, 2011 Author Posted April 5, 2011 Bro please it would be helpful for me as well as the community if you could graphically show where was the fault and how u fixed it, I mean detecting the faulty diode, how u opened the CDI unit...etc..I hope u could open it up once again for us..that sort of issue can come up for any of us XV125 users so please share it in detail.. Thanx.. Hi Kelum, I will post full detail with photos up today as a new topic. Regards Dan
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