Kelum

Me too Paul I dont go to mechanics now..I do all the repairs now by looking at manual and web info. They scratch and damage my baby everytime ruthlessly..sometimes they know nothing of the technical stuff but just to remove and fit in..but telling lot of crazy stuff..they have a one protocol for all the bikes..I love my bike and I know nobody gives her the care I do...lemme work on it...I like your attitudes mate, my kinda man! I have bought multimeter and all the tools..Paul can u peep into my battery overcharge case too?

Rectifier. When a coil produces electricity, it sends it out in plus or minus waves. The battery can only charge on one of these waves. A rectifier has silicon diodes that only allow half the wave to get through. Back in the 60s and 70s a lot of the little bikes had these single wave rectifiers. Now most bikes have full wave rectifiers that have four diodes. All this rectifies the AC current to DC to charge the battery. To test the rectifier, hook up the ohmmeter leads to one of the wires and to the ground (mounting) stud. Note the reading you get. Now reverse the leads from the ohmmeter and note the reading again. The exact reading is not all that important, but there should be a big difference between the two if the diode is working right. Test each of the wires this way. If any wire is very close in the two readings then the diode is leaking and no good. If there is no continuity, then the diode is shorted out and no good. Be careful not to turn the bolt holding all the diodes together. This can short them out. It is possible to test the rectifier with a circuit tester by adding a D flashlight battery in line with the circuit tester. You want to see the light, light in one direction and not in the other. If all of a sudden you start blowing the main fuse, it's possible one of your rectifier diodes has failed, letting current, from the battery flow back to ground. Voltage Regulator. All the current from the charge coils would over charge the battery if we let it, so we need a voltage regulator to keep the battery charged at 12 volts. Your ohmmeter should have a DC volt scale. Set it at 20 volts and connect the positive and negative leads to the right battery terminals. Make sure the battery is fully charged, so we get a correct reading. Start the bike and rev it up. The volts should go up to 13.8-14.5 volts and then stay there. Much more, and it will over charge the battery. Much less, and the battery will never charge up. Some voltage regulators can be adjusted and some cannot. If you can't get it's cover off or if it is all sealed up, it's non adjustable. If you can get the cover off, you can clean the little contact points and adjust it with a screw driver till you get the right charging rate. Most, nowadays, are not adjustable. Most of the newer bikes have the Rectifier and Voltage Regulator as one unit. If either one goes you have to replace both. AC current will light the headlight and everything else. Light bulbs don't care if it's DC or AC current. If you have a dirt bike and don't need a battery you can get an after market voltage regulator for $30-40 and it will keep you from blowing bulbs. A number of the older, smaller, bikes had no voltage regulator. I guess they thought the battery would soak up the extra current... they were wrong, so put one in. There also is a cheap after market rectifier/voltage regulator unit you can put on, if you need a battery. It will also work on some street bikes too, but you have to make sure it matches the charging system.

ok bt since bike doesnt have a rev counter how can I check revs at 5000? regulator not doing its job for sure mate..will see..

anyone please?

Thats a good idea mate, try strengthening it up..

He's referring to this I guess. I have seen cheaper versions of this on ebay. However, by some means if you could make a metal version of it, it will last longer..I dont see a reason why Yamaha has put a plastic one instead of a lasting metal one.. Mine is getting cracks too I think I will have to buy one.

Week ago I bought a new battery for my xv125, filled sulfuric acid to upper level and let settle overnight..and installed it and last night I the headlight was flickering..dimming and brightening So I removed the battery to find out all the acid levels in 6 cells to have gone down terrible, no didnt get rotten egg stink. I think my previous battery was ruined by the same case, it too had fluid level running down issue frequently..now that I have placed a good battery so I think regulator not doing its job properly. I checked the bike circuit and found 3 white wires coming from AC Magneto connecting to regultor/rectifier and all the wires are presently connected as per the diagram below. Uploaded with ImageShack.us I have to make a special note, right after few days I bought the bike, rectifier died, so I bought a new one with the similar code, it was a one disassembled from a virago..code is SH6400D-12...I wonder if the guy who installed the second rectifier messed the wire connections in the socket, I would really appreciate if someone could post his wire connection configuration to the rectifier here. Seems the rectifier I bought was a faulty one. It kills batteries..am scared if my new battery has been ruined already..please someone help..thank you.. P.S. in my previous battery I had light flickering, fluid run-down issues plus in worst cases, SO2 formation..sulfuric goes away as sulfur dioxide...rotten egg under my seat..

Yeah many engines have faced severe issues here..some badly damaged..I really dont like letting mechanics toy with my carb and engine..I remember what one had done to the carb of my previous Honda Benly 125..he had put a different jet and didnt give me the original..didnt even tell me what he did... What about fuel pump and cock Paul...I saw may be in the manual u could clear them too, fuel cock has a filter too right?

Thanks Paul, once water deposits removed everything will be ok?

Sri Lanka had imported a low quality petrol lot recently and it had water in petrol, if u take a sample from a gas station to a bottle there would be a water layer at the bottom. The lot was being distributed all around the country and many engines have gotten issues..government has cancelled paying for the supplier. But both supplier and the careless authorities are to blame. Now in my xv125 I had a miss when I hit start button, engine would start normally and run 3-4 cycles and like it doesnt have fuel it would stop..I first got amazed on this and was very scared I have an engine problem. This went ok in few days and now it starts at my first button hit. Yet it has a very strange miss in the engine when I ride..bike suddenly slowers and gains normal speed again (I was almost hit by the driver at my tail) I asked frnds of mine and they too have this strange miss.. Now my prob is, what harm can water in petrol cause to your engine, would a carb and filter cleanup do? Since water stays at the bottom and petrol on top, it should probably be blocking fuel supply to carb. Does the xv250 service manual has steps to clean carb and pump and filter/fuel cock? are there seals or gaskets I should be careful not to damage? I keep reading what water can do to ur engine...I know normally over the time fuel lines can have some water deposits. Is there a particular means or trick Yamaha has given to clean up carbs without removing? I saw in Indian bikes there is a bolt and a small hose running from carb bottom..xv125 having one? I really appreciate ur opinion here people..thanks!

Yes Cynic you have a point..but the brightness can be reduced by lowering or reducing the number of LEDs being lit..over those there are several advantages in buying some bigger LEDs and using them in your bike..I bought 15 such LEDs today but they dont have a bigger reflector in them like those u see in LED headlamps... They last very long consume less electricity. No ordinary filaments so shock resistant Brighter Light is similar to daylight so very great on eyes..

Well buddy, if you can browse on the internet u can find more than enough LED circuits where a large number of LEDs have combined together to focus light to a particular target..having read ur post hear with the video, am thinking of making my own LED headlamp for the bike..LEDs consume less electricity so it is possible to have a large number of them connected together to be powered up by the headlamp light power lead. Small LEDs wont be bright enough so u should go for bigger ones that can be found in flashlights etc, or can purchase bigger LEDs..possibilities are endless that by altering the number of LEDs powered at once, u can switch between different brightness levels..plus there are 3 color LEDs so can have a very nice headlamp...I am going to work on it..u could use ur OLD mercury cup of the headlight.. Do not stare at high brightness LEDs, because doing so may cause permanent damage to your eyes. The optics of our eyes focus visible light onto the retina, which is the light sensitive part of our eyes, similar to the way a magnifying glass can focus an image of the sun onto a piece of paper. Just as the piece of paper might smolder and catch fire, a light that is brightly focused on your retina can cook and thus permanently damage your eye. Exposure to bright white and blue LEDs can also cause permanent damage to your eyes through photochemical action. Here is a link to an article about the particular hazards of blue LEDs: http://www.mdsupport.org/library/hazard.html#blue If yo could find bigger ones like this links show u...u can achieve a greater brightness.. http://www.elecfree.com/led-car-headlights/ http://www.jedc.org/forms/LED%20Circuits%20and%20Headlights%20for%20the%20SeaPerch%20ROV.pdf This will give u the idea..but be creative to have the best beam by using brighter bigger LEDs..avoid smaller ones.. http://www.resurgentsoftware.com/perfect_led_light.html am making one..will make a thread here..

Yep they are huge, too bad authorities dont allow riding them in Sri Lanka..engine capacity limited to 125cc and 250cc..

caught ya..thanks..

I saw they place optical fibers on a cadilac modified cruiser..I think switching on to LED lamps would draw less current from battery plus they are durable...optics should be placed where they appear good mate..I like the luminous appearance in them...what is a 12 volt switch mate?

Fused means mate? What was the rusty bolt thing?

??????????? didnt catch u???

This is the thermo switch..and suspected wires which should fit with it..but they have no poisitive negative leads.. Uploaded with ImageShack.us

Hi guys... I am thinking of putting additional lights on my XV125. Like two small front lights below or above Headlight..and some additional horn..I saw in the store a set of side mirrors and each had speakers on them..you could place ur micro sd memory chip to play songs while u ride or simply listen to FM radio.. My problem is if you want such gadgets fixed onto bike...how would u take the power from wire harness..are there special places in the circuit where u could get power from? I found two free connectors so far in the headlight, and one under right side cup where relays are...what are they for? Extensions for additional stuff..? Also since my thermo switch is disconnected ...the two wore leads also remain free...but they come from the bikes circuit diagram, I think I shouldnt mess with it..does thermo switch has negative positive polese, how do u identify them..plus how do u test if my thermo switch is ok using multimeter? Of course if you go for additional lights and all...you should update your fuses..high amperes right? If you want to connect a GPS system or a remote/security system..how would u start..I have xv250 circuit diagram...would these modifications affect badly on ignition system and starter? Fiber optics (like in the Movie Tron) powered by LEDS seem to be cool..you coul do wonders with them..what about their applications on xv125? Has anyone tried? Ur advice will be highly appreciated..

Ya its oil, ok mate I will be very careful...

Thank you mate, I will follow those steps,,..thank you

Vinegar is a mild acid mate, sure it can dissolve rust when there is rust, it can also increase rusting or oxidization of metals..that means it can also corrode metals..from my chemistry lessons..

vinegar is acitic acid, it doesnt corrode metals?

Ok mate, thanks for the info, I bought a GREY 999 Gasket maker imported from US...The bolts there are very difficult to remove, lubrication would work?

Hi..yes I have gaskets, but am waiting cos I need find good someone to put them, may be I woud be able to do it, waiting for some help, like from one of u..