Kelum Posted June 14, 2012 Posted June 14, 2012 Hi all, I have cleaned and tuned her carb, filter and even petcock..checked all the connections and wires. But still there is this engine stop coming on and off while riding. It is expressed to the outside as a sudden slowing..prominent when u ride on low gears like in heavy traffic. This slowing happens but least powerful when riding at high speed. Its more cruel when u are on low gears it actually stops bike. So whenever that pup sound comes I squeeze clutch so engine starts again. Say engine and bike stopped, sometimes I have to press start button several times to start again. I checked stator resistance, continuity, continuity with crankcase, same with pickup coil, TCI connections, etc. I suspect those two transistors in TCI unit. There is nowhere else for me to turn. The best clue is I remember when I was checking sparks I noticed a break in sparking. I still smell unburnt fuel. So am guessing during this slowing, the spark stops for a moment, during this even the carb sprays fuel vapor, however its not burnt without spark and comes out from exhaust manifold. At times the unit remains non-responsive so it becomes hard to start, but suddenly it works like dynamite. Please forward your TCI unit symptoms for me to catch the problem up. Thanks!
Moderator Airhead Posted June 14, 2012 Moderator Posted June 14, 2012 has it got a sidestand switch kelum?
Kelum Posted June 15, 2012 Author Posted June 15, 2012 has it got a sidestand switch kelum? no side stand switch..
Kelum Posted June 15, 2012 Author Posted June 15, 2012 Bad earth's,,,,,,,, engine and frame ?? I removed and refitted them. They are ok.
Kelum Posted June 17, 2012 Author Posted June 17, 2012 Bike stopped responding to starter motor. It cranks and gidi gidi sound coming, which means it attempts to start but doesnt continue. The mech said the the unit may be faulty. Used units available at 60 USD while reconditioned available at 120USD. Sparking happens at plug ends and plug wire ends. I just checked battery voltage its 15.5 volts. This is unusual and I remember I had once poured sulfuric thinking it was distilled water. Amount of acid strength may be high and that high voltage has killed the CDI? This mistake happened months back but the bike has been running well upto now. Anyways I guess I will have to buy a new battery if am going to replace CDI, may be ignition coils and rec/reg. Am going to check transistors of the CDI with multimeter now.
Moderator Airhead Posted June 17, 2012 Moderator Posted June 17, 2012 maybe your voltage regulator isnt working...havent we been here before?
Kelum Posted June 17, 2012 Author Posted June 17, 2012 maybe your voltage regulator isnt working...havent we been here before? Yes possible, am going to replace all...lets see..this is not originally the thread all about..I want to figure out if my Unit is blown..
Moderator Airhead Posted June 17, 2012 Moderator Posted June 17, 2012 yes but my point is...if the regulator is faulty, this could be what is damaging the battery and possibly the CDI. I think you should check out the regulator function as a priority
Kelum Posted June 18, 2012 Author Posted June 18, 2012 'Guys, I have no means to check the ignition coils and CDI. Now that the bike is totally dead. I overhauled carb, cleaned jets and cleaned fuel pumps and petcock, even the breather pipe. Then tightened rubber airway on top of carb with a copper wire. Then checked wiring too, coils and CDI contacts, then pick up continuity, earthing. All are fine. After all these I cranked engine with starter. There is a "dig-dig" sound, engine attempting to start. But doesn't hold on. I took it out and pushed, engine is totally dead. It doesn't even make a sound. I checked sparking while pressing starter button and there is bluish spark. Even if CDI is faulty, can there still be sparks? Even if ignition coils are blown, can they give sparks? I am certain now that the problem is electrical.But cant figure out which part is faulty. Since there was power loss in front cylinder and "fut-fut" sound, am guessing either the ignition coils or CDI has to do something with the issue.'
Kelum Posted June 20, 2012 Author Posted June 20, 2012 Ok, I bought a TCI today for 100USD...it doesnt have the 4RF- code number my older one has. Instead it has 3DM-82305-01, I browsed web and this new one seems to be of a XV250. I hooked it up but bike doesnt start. I think theoretically 250 TCI should not be working on a 125 as speed limits, revs etc are different, can anyone tell me what to do? They tried hard they couldnt find a 4RF.
Kelum Posted June 20, 2012 Author Posted June 20, 2012 yes but my point is...if the regulator is faulty, this could be what is damaging the battery and possibly the CDI. I think you should check out the regulator function as a priority I bought a new reg/rectifier too. Probably it had killed TCI. Now that I have been given a TCI of a 250. It doesnt work on 125 right? Am going to return it tomorrow. I installed it and cranked engine, it doesnt start.
2 Wheels Posted June 20, 2012 Posted June 20, 2012 I took it out and pushed, engine is totally dead. It doesn't even make a sound. I checked sparking while pressing starter button and there is bluish spark. Even if CDI is faulty, can there still be sparks? Even if ignition coils are blown, can they give sparks? .' To the best of my knowlage No No Dont think there is a way to check the TCI. Its either dead or working ! If you have spark and getting fuel,,,,, then engine should fire up,,,even if it runs poorly. Dont know what the prob is with the bike. Mabey the timing has slipped !
Kelum Posted June 20, 2012 Author Posted June 20, 2012 To the best of my knowlage No No Dont think there is a way to check the TCI. Its either dead or working ! If you have spark and getting fuel,,,,, then engine should fire up,,,even if it runs poorly. Dont know what the prob is with the bike. Mabey the timing has slipped ! Few days back the mech adjusted timing, how can timing go slipped buddy, is it possible that it sparks but weak? Can a 250 TCI work on a 125? Can I adjust timing by myself?
Moderator Airhead Posted June 20, 2012 Moderator Posted June 20, 2012 as far as the timing goes i can 'slip' because of either 1 or 2 things 1; the stator screws have come loose and the backplate has moved or 2: The rotor woodruff key has sheared because the rotor wasnt torqued up to the specified torque setting
Kelum Posted June 21, 2012 Author Posted June 21, 2012 as far as the timing goes i can 'slip' because of either 1 or 2 things 1; the stator screws have come loose and the backplate has moved or 2: The rotor woodruff key has sheared because the rotor wasnt torqued up to the specified torque setting Timing adjusted, but still it doesnt start, heads disassembled, tomorrow hopefully I will find a clue, compression of both cylinders ok, timing chains ok, checked stators, they are stable. Am getting sick of bikes ....
Kelum Posted June 22, 2012 Author Posted June 22, 2012 Guys.. Well these mechs confused me telling this is your prob and that is your prob...Today I forcefully made a mech to open the engine as the carb was ok and the electrical system was ok, since there was a spark, there should at least be a weak start of the engine. But even when pushed hard she would start but doesnt hold on. It was way too hard to push it. We opened front cylinder head to discover no lubrication in piston and bore, worn steel dust on the rod, revolving was so hard, now we had a clue of the pump malfunction, then mech removed a small bung underside crank case to find a filter cup totally blocked with debris, just like spider webs, we cleaned it up. Now mech's suggestion was this clog was the prob. He was to clean it and stop there. But I insisted we need to check the pump as same debris might have clogged pump, he was reluctant to open but he finally opened clutch cover to find out pump plastic wheel had lost several teeth. I could buy small pump wheel and a steel substitute for the larger plastic wheel and we replaced old ones with the new. In the evening we reassembled the engine and mounting on frame tomorrow. Some unknown force has saved me from a huge trouble. Or that may be a safety feature in virago as by the time engine stopped I was riding at ~60kmph. But it didnt crash. Bores and piston heads, rings etc. all ok. But there were steel dust on rod so there had been some abrasion. So, see the symptoms I had: When u ride at a good speed bike suddenly and gradually loses power and stops. It starts as if nothing happened after about 10mins. There was some knocking I had described earlier. When pressing start button, I heard gidi gidi sound inside. Sparking ok. Sound indicated it tries to start. Pushing was very hard. Hard push started the engine, but very less power for some time, it didnt want to hold on, bike could never be accelerated. These two symptoms led mechs and even myself to believe only one cylinder was firing and that no acceleration came from a diaphragm fault in carb. But both cylinders were hot. I even bought a 250 TCI, new rec/reg - which was a necessity of course...and was almost planing to buy new ignition coils. I think my virago didnt ruin itself for some reason like the TCI could sense the elevated friction inside engine..I dont know..something saved me. But tomorrow we gonna have to check if she starts, wish me good luck..
nick004298 Posted November 2, 2013 Posted November 2, 2013 Did you get to the bottom of this problem as my sons YBR 125 is having similar problems, Have cleaned carb changed coil, new plug and plug cap but still cuts out after running when gets hot then leave for a couple of hours and its ok again, then after warm will cut out.
RatBob Posted November 9, 2013 Posted November 9, 2013 Did you get to the bottom of this problem as my sons YBR 125 is having similar problems, Have cleaned carb changed coil, new plug and plug cap but still cuts out after running when gets hot then leave for a couple of hours and its ok again, then after warm will cut out. Might be a weak/failing oil pump. When oil is cold it is thinner, when it warms up it becomes thick so that it will stick to the moving parts to lubricate them properly. If the oil pump is weak then it will not be pumping correctly and it might be that due to a lack of oil the engine is losing compression, therefore loses power and stalls. Do not run the bike in this condition, absolutely take it to a mechanic and have the oil pump checked and have a compression test done.
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