Kelum Posted May 20, 2012 Share Posted May 20, 2012 Hi guys, My bike has become a terrible crawler as it doesnt pick up properly. So every time I want a reasonable speed I have to accelerate more so more fuel consumption. And I feel the plugs do overheat, even the porcelain white part has become brownish, front cylinder accumulates carbon deposits on the plug. I sense unburnt fuel everytime the engine running. I tried replacing plugs with two older ones (as shops are closed today) but still the problem seems to continue. Whats more when I accelerate it gradualy increases revs and tends to stay at a particular rev speed even if I release my hand from accelerator Engine stays stuck at a higher rev even when the accelerator comes to rest position Oh gush I feel like my good days are gone..please help me determine this issue..thanks in advance! Link to comment Share on other sites More sharing options...
Kelum Posted May 21, 2012 Author Share Posted May 21, 2012 Where have all the helper boys gone? please please... Link to comment Share on other sites More sharing options...
neversaydie Posted May 21, 2012 Share Posted May 21, 2012 Hi guys, My bike has become a terrible crawler as it doesnt pick up properly. So every time I want a reasonable speed I have to accelerate more so more fuel consumption. And I feel the plugs do overheat, even the porcelain white part has become brownish, front cylinder accumulates carbon deposits on the plug. I sense unburnt fuel everytime the engine running. I tried replacing plugs with two older ones (as shops are closed today) but still the problem seems to continue. Whats more when I accelerate it gradualy increases revs and tends to stay at a particular rev speed even if I release my hand from accelerator Engine stays stuck at a higher rev even when the accelerator comes to rest position Oh gush I feel like my good days are gone..please help me determine this issue..thanks in advance! Hi Kelum, Sounds like carburetor trouble to me. Start with the easy first, are the throttle cables free in the outer sleeves, i.e. not sticking when you ease of the throttle. If so, pour some engine oil down the outer sleeve till it runs out of the other end. Where the cables fasten onto the carb, does the unit spring back easily? Is the rubber sleeve on the carb free from splits/cracks etc? Ray Link to comment Share on other sites More sharing options...
blackhat250 Posted May 21, 2012 Share Posted May 21, 2012 Hi Kellum " sounds like airleak on the rear cylnder, [ hot - high revs- light brown plug,] and over-fueling on the front cylnder, [ carbon -soot] ,,,,float level needs checked on front, Link to comment Share on other sites More sharing options...
Kelum Posted May 22, 2012 Author Share Posted May 22, 2012 Thank you guys for all those replies, let me check and update you...so far I checked both ignition coils, wires, replaced plugs, caps and wires..oiled the accelerator cable also, but still high revs. Its odd right after removing soot on plugs and putting back in the bike goes well for about 2km, not best acceleration but I would say better, then all of the sudden acceleration goes away...means am on a single cylinder...I think engine runs good till carbon deposits build up..and dies right after that... Will keep u updated, thank you for all the wonderful suggestions. Link to comment Share on other sites More sharing options...
Kelum Posted May 22, 2012 Author Share Posted May 22, 2012 Hi Kellum " sounds like airleak on the rear cylnder, [ hot - high revs- light brown plug,] and over-fueling on the front cylnder, [ carbon -soot] ,,,,float level needs checked on front, How can you check float levels of front buddy...is it easier to do? I dont usually go to mechanics as they EAT bikes..can I do it myself? Link to comment Share on other sites More sharing options...
Kelum Posted May 22, 2012 Author Share Posted May 22, 2012 Hi guys, here comes the update. I removed the carb, and the rubber thing that brings air from frame into the carb. There were no cracks in it, and it properly seals the frame end and carb end. Then the Y shaped rubber pipe the feeds fuel-air mixture into cylinders, well it did have cracks but they were only on outside and however in order to make sure they form no leaks, I applied a gum that is used in plumbing on outer surface to cover all the cracks. As a whole, I dont see cracks or air leaks have anything to do with this, as ray suggested, the throttle cable was oiled and it springs back properly. After all these removal n checkups, I had a ride of nearly 20 kms but the issue still there, bike is terrible when it encounters mounts. But speeds up on steepy parts of the road. I clearly feel missing/intermittent sparking/burning inside cylinder(s)...the boh boh sound proves it. More prominent when I shift gears. To maintain the normal speed I have to turn accelerator to its maximum end, which means more fuel. Still unburnt fuel smell coming. The engines locks at high revs. I am thinking the ignition coils causing broken sparks. And therefore, power strokes become irregular, this irregularity of burning causes carbon soots to build up on spark plugs making spark surfaces least conductive. So after some time of operation the sparks become so weak or no sparks. Thats why initial good pick up which later turns out to be bad. I always have suspected my ignition coils but I know they dont easily become faulty. Am going to ask a technician to chek them tomorrow. What do you guys think of my assumption? bad sparks can also result in unburnt fuel plus less power right? I think this is an electrical issue. Can you tell me is it the pick up coil that breaks the circuit in a bike? Coils produce that huge amount of electricity only when the circuit is broken and the pick up coil does this according to engine's speed of rotation, that I know. It will be ok to replace ignition coils, what are the possibilities for this issue to have worsened more and more? Coils do not have a connection with the CDI Unit? or do they have? Could a faulty CDI unit create the same missing in engine? This problematic thing in front cylinder was there since the begining, there was a put put sound inside the cylinder.But it never became so obvious like it now is. Please guide me through this guys..thanks in advance. Tell me where do ignition coils get those four wires from. I dont want my CDI unit to be faulty, its very pricey. Link to comment Share on other sites More sharing options...
Kelum Posted May 23, 2012 Author Share Posted May 23, 2012 Well, this morning the electrician found that the electrical system functioning properly. So I turned back to the carb, found a more qualified technician specialized in carbs. He took almost 9 hours to tune petrol flow and had several test rides, now the plugs are white, beat is more stronger, and the engine rocks, so damn powerful, it cost me just 10.2 bucks for him... There is an intermittent knock though..he said it requires looking into both cylinders, so planning to work on it later on...thank you all for the help guys.. Link to comment Share on other sites More sharing options...
neversaydie Posted May 23, 2012 Share Posted May 23, 2012 Well, this morning the electrician found that the electrical system functioning properly. So I turned back to the carb, found a more qualified technician specialized in carbs. He took almost 9 hours to tune petrol flow and had several test rides, now the plugs are white, beat is more stronger, and the engine rocks, so damn powerful, it cost me just 10.2 bucks for him... There is an intermittent knock though..he said it requires looking into both cylinders, so planning to work on it later on...thank you all for the help guys.. As suspected, carb trouble then. 10.2 bucks for 9 hours labour I dont know how much a buck (I said buck) is, but it sounds like remarkably good value Link to comment Share on other sites More sharing options...
Kelum Posted May 24, 2012 Author Share Posted May 24, 2012 As suspected, carb trouble then. 10.2 bucks for 9 hours labour I dont know how much a buck (I said buck) is, but it sounds like remarkably good value He he actually in Sri Lankan rupees it was 1200/- which is roughly 10.2 USD. Yes the bike is more powerful and propels great. The last time I checked the plugs were white too. But there is this sudden stop which I told the technician about. Engine stops after some running as if it lost sparks, and at this very moment if I squeeze the clutch then engine starts again, this should be done before bike stops. I had a two terrible situations on the highway today, fortunately there were no vehicles queuing from behind when bike stopped on the middle of the highway, I quickly neutralled and started and luckily she roared again. This embarrassing and risky thing normally happens.. Engine's operation is not smooth, I think its knocking in the engine. As you ride at high revs, at times there are sudden slowerings followed by picking ups. This happens withing few seconds so the effect doesnt seem to affect speed but it does cause a heavy strain on rear wheel, sprockets and the chain. I often have to adjust rear tires as the chain slack increases so soon. I feel like the engine stops firing for few seconds and starts again. What do you guys have to tell on this? Sounds electrical? or does it originate inside cylinders? The mechanic said for rectifying knocks he will have to open the cylinders. Link to comment Share on other sites More sharing options...
neversaydie Posted May 24, 2012 Share Posted May 24, 2012 Just a thought Kelum, what condition are your chain and sprockets in? I suspect that the climate and roads in Sri Lanka requires regular chain maintenance. Is the chain too stretched, is there plenty of meat left on the sprocket teeth, is the chain tension set as per the owners manual? Link to comment Share on other sites More sharing options...
Paulwhite Posted May 28, 2012 Share Posted May 28, 2012 hi kelum am i right in thinking that you will come to a stop and the engine will cut out? also you say it slows down then goes again whilst riding? that sounds like a fuel line is blocked. or the float needle gets stuck. that "knock" dont sound good, the xv 125 engine is known to have a week crank shaft.....how many miles have you done? Link to comment Share on other sites More sharing options...
Kelum Posted May 30, 2012 Author Share Posted May 30, 2012 hi kelum am i right in thinking that you will come to a stop and the engine will cut out? also you say it slows down then goes again whilst riding? that sounds like a fuel line is blocked. or the float needle gets stuck. that "knock" dont sound good, the xv 125 engine is known to have a week crank shaft.....how many miles have you done? Hi Paul...I have done around 56000km by now. Yes...the engine frequently clogs and goes..I checked everything from connectors to coils, battery, rectifier and then opened fuel filter, petcock, even gas tank lid to make sure its vent isnt clogged, then ignition key contacts, engine kill switch..cleaned them all...carb opened, do you mean the little rocket-shaped thing that goes in and out locked to the carb float? How can I fix it? Now the plugs are white so burning well, acceleration great but still even at top speeds I feel continuous fuel blocks that stops engine firing for a sec. Bike slowers suddenly but catches up speed..when I slower the bike say in heavy traffic, bike tends to stop at such fuel cutoffs..last week this happened in the middle of the highway when I slowered at a round-about..argh.. The mechanic couldnt figure out why this was happening he said the TCI unit was faulty which I wasnt ready to accept. I cleaned fuel pump and petcock and there was water inside petcock. Before cleaning bike stopped starting and now tht prob's gone. But like u said there is a carb issue, I mean continuous clogging or some blocking. How can I fix it...well I dont know if it is a knock and sure it may be straining the crankshaft. Did you mean that? I tried to unscrew carb needles but their gooves are broken so cannot be removed...should I use WD40 to clean needles? I would appreciate if you or someone could post here xv125 carb cleaning procedure and tuneup. Ray - I frequently oil sprockets and chain and adjust the slack to the standard. Dusty but I clean them...so I feel that the prob is in the heart of bike; carb. Link to comment Share on other sites More sharing options...
Kelum Posted May 31, 2012 Author Share Posted May 31, 2012 argh...the bike is picking up good now, today, the carb started to lock the gas flow again..the result was the earlier rev lock, more prominent when starting at neutral and shifting gears..it revs like hell right after I squeeze clutch for gear shifting... What do you guys have to say on this? is this repairable? should I buy a carb repair kit (not available here of course) or find a used carb from somewhere (which wonbt be easy anyways)? Link to comment Share on other sites More sharing options...
Kelum Posted May 31, 2012 Author Share Posted May 31, 2012 Carb flooding, the correct term. constant backfires.. Link to comment Share on other sites More sharing options...
Kelum Posted June 2, 2012 Author Share Posted June 2, 2012 Hello guys? Link to comment Share on other sites More sharing options...
neversaydie Posted June 2, 2012 Share Posted June 2, 2012 Before stripping out the carb, try running some carb cleaner through the fuel system Link to comment Share on other sites More sharing options...
Kelum Posted June 3, 2012 Author Share Posted June 3, 2012 The problem became a huge headache I took bike to two technicians. One guy said there was an air leak, and he didnt like to fix because he had to remove petrol tank and hoses to get to the carb, the other however had a different approach and he cleaned the carb better and said the petrol flow wasnt enough. After his explanation I felt the same as when I go slowly there were constant engine stops. He loosened the flow screw and now starts ok but I have to press start button longer now to make motor to start the engine. However the stop of the engine is still there, but unlike earlier its somewhat rare. Now I have concluded, the petrol flow is ok, there is a problem in the TCI unit, it cuts down the spark for a sec or two which results in stops. I have thought of checking the two power transistors! Link to comment Share on other sites More sharing options...
blackhat250 Posted June 3, 2012 Share Posted June 3, 2012 Kelum" start with the basics, unplug all connections [ one at a time] clean and reconnect, even the C.D.I. as bad connections over time can cause these symptoms, look for broken / worn wires, Link to comment Share on other sites More sharing options...
Kelum Posted June 12, 2012 Author Share Posted June 12, 2012 Kelum" start with the basics, unplug all connections [ one at a time] clean and reconnect, even the C.D.I. as bad connections over time can cause these symptoms, look for broken / worn wires, Hi, there is a kraas sound during starting, I thought the prob was the motor but the technician said the wheels have worn out, I didnt remove the cover though as I plan to put new oil at the same time I fix that problem, motor wheels have worn out probably so I have to long-press start button to start the bike. Back to the issue of carb/CDI...now that the bike is more powerful, but still that knock keeps coming, when you rev at idle there is the unburnt fuel smell...now that I have checked everything including coils, pickups, stators, carb etc having them upto the specs...the CDI seem to be sending intermittent signals to bores...checked connections also and cleaned them...intermittent signals means there is a second or two gas doesnt burn and coming out thru exhausts..and then into my nose.... I heard these power transistors can go nasty...there was a link here to buy them for replacing rather than the whole unit. What do you think of the situation guys? Link to comment Share on other sites More sharing options...
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