honda_freak

Hi. The regulated voltage should be between 13.5 to 14.5 volt at 1800 RPM - so 12.5 volt is definitely to low. If voltage is low when engine is running - must it be very low during cranking of the engine and if the lower threshold at 6 volt to activate the ECU isn´t reached it wouldn´t start. As "thall1" mentioned the condenser wiring could be bad - so it would be a good place to start your diagnostic search. One thing to remember about the batteryless system is how important the condenser is during start of the engine. Hope you make it work. Regards Honda Freak

When you can not activate the fuel pump manually with a 12 volt battery externally connected, so the problem must be inside the fuel pump. Try to measure the resistance at the fuel pump connector, when you can not activate the pump by 12 volts from an external source like a battery. Another thing regarding the fuel pump connector is to verify that the power and ground wire is not wrongly connected inside the 2 pin connector !!! As the fuel pump is operated as dc motor, it could turn the motor the other way around if the wires are misplaced inside the connector.

Hi thall1 Your rectifier/regulator result seems fine if you remembered to push a little on the terminals pins as I've told before is this part very vital for a correct result. One thing about the fuel pump motor. Since this is a DC motor it may have points on the commutator, which has higher resistance than the other, thereby having difficulty to start the fuel pump motor. Can you meassure the electrical current to the fuel pump wit a DMM or a current clamp !!! Have you tried with a new capacitor !!! Regards Honda Freak

I dont know whats wrong with this attachment file, maybe the web administrator at this forum could have a look at it.

Hello Thall1 The resistance control you are referring to in the workshop manual is the resistance of the charging coil from the flywheel - there is no test of the rectifier / regulator in the workshop manual. The file I uploaded here describes how to test the diodes inside the rectifier, so if you know how to use a digital multimeter should be an easy task to accomplish. You must remember to push a little on the terminal pin, when making this test, or you can get a false reading. I hope you will solve this problem or at least get some answers on what to do next ! DIODE TEST.pdf Regards Honda_freak

Hi From this webshop http://www.cmsnl.com/products/unit-assy-condenser_31700nn4003/ you can buy the requested 10 uF condenser for your Honda Montesa 4RT. Regards Honda Freak

As Jonnyc21 already had shown here about to test a capacitor - wouldn't I repeat what he has written other than to say - that the capacitor is very vital part of the battery-less system and without the help of the capacitor during startup is it nearly impossible to start. What I think you should check on your trial-bike has something to do with ECU voltage on terminal pin 5 on the ECU. Without five volt on this terminal 5 wouldn´t the ECU be able to activate the ignition and the fuelpump system properly. Before you make this measurement be very carefull not to bend or break any terminals pins. You could make some extension leads to put in the ECU connector. Remember when you make this mesaurement to put your DMM to record peak value as this voltage are not a steady reading or else you would get a false voltage reading. Based on the result of that test - another test of the flywheel generator coil and recitifier / regulator may be necessary to conduct. BTW is there a consistant blue spark between the sparkplug electrodes !!! Regards Honda_freak

It seems like the fuel injector are getting it fuel backwards through the fuel pressure regulator - that's odd. Maybe the fuel pressure membrane are faulty !!!

What fuel line are you talking about - is the fuel feed hose or perhaps the the fuel return hose !!!

You could have a potential short circuit in your fuel pump or in the wiring harness. Remember that the red power cable that feeds the fuel pump also deliver power to the the other components on the bike. But, if the bike runs without fuel pump electrical connected - would I suspect the fuel pump to be faulty. Can you hear or feel if the fuel pump are running !!! Regards Hond Freak

Hi This thread http://www.trialscentral.com/forums/topic/56730-4rt-no-spark-help/page-2#entry404207 that I comment may give you another direction to follow in terms of diagnostic possibilities. I'm not saying it would solve your problem, but it is good with another objective view on how to troubleshoot such a problem as missing spark. Regards Honda Freak

Hi The first thing you must check is whether or not the kill button/switch is working correctly. Try to disconnect the two wire running to the kill button and see if the spark plug gets its sparks back between the electrodes. Regards Honda_Freak

To be quite honest I don't think the trick with idle adjuster screw is the main cause to the missing spark although it seem to work this time. After have read your first post again, have I come to another conclusion or a theory regarding the missing spark you had experienced. It has something to do with low engine rotation speed which could be caused by clutch drag. According to the patent document from Keihin Corp. battery-less system is there a claim regarding "low engine speed " that says if the rotation speed falls below 600 RPM it should abort the startup sequence. It's just a thought I wanted to share with you. Best regards Honda Freak

Hi there. Here is my story of a Honda Montesa 4RT from 2005 with ignition problems there maybe can help you !!!. I had a call from the local Honda Montesa dealer here in Denmark which told me that he had got 2005 Honda Montesa 4RT with some strange ignition problems that the owner of the bike had given up on.The owner had done a lot of things to get the missing spark back on his Honda Montesa 4RT by swapping part from a doner bike and still with a negative result - no spark. The first thing I did were to confirm whether or not there were spark at the spark plug and there was no spark at all. Then I made a resistance-test from the ECU to the individual components with a good result - which was perfectly fine and normal readings. A dirty test of the condenser can be done with a multimeter with the settings on ohm scala and the measurement done across the two terminals on the condenser - a good condenser should show infinite resistance or (OL) on the multimeter. The next thing I did to verify that the bike wasnt producing any electrical current was to connect a 12 volt automotive battery to the wiring harness of the Honda Montesa 4RT. The first thing you must do to make this test is to disconnect the electrical connector coming from the flywheel alternator and then disconnect condenser plug and connect a 12 volt battery to the condenser male plug. When I first made this test, I got a strong spark at the spark plug and then I knew it was the bike that did not produce an electrical current or perhaps the electrical current wasn't being at the rectified at the rectifier/controller. I already knew that the condenser was good, so the only thing left on my diagnostic game plan, was the rectifier itself. The strange thing about this test is, there isn't any diagnostic test shown in the workshop manual of the Honda Montesa 4RT. The next test was to test the rectifier/controller with a multimeter setting in diode setup and a diagram showing the electrical connection inside the rectifier. My test showed a bad diode inside the rectifier, but here is the tricky part of my diagnostic test, it only shows poor connection when i push a little on the terminal pins, so sometimes there is connection and other times not !!!!!!!!!. I got a new rectifier/controller and the bike started first time I hit the kickstarter. Here at the end I want to say, be very careful when you connect the 12 volt battery to the wiring harness of the Honda Montesa 4RT - that you didn't make any short circuits if you decide to follow my diagnostic game plan. I hope you will find the root cause to this problem as I did. Best regards Honda Freak

Have you tried with a new spark plug ! The right way to test the ignition system is to use a spark plug tester. I know what you are thinking - everybody else just places the spark plug on the cylinderhead or a place where are a good earth path, but it´s not the right way to test a sparkplug. You should use a sparkplug tester - that way you are sure that the ignition system have the ability to deliver maximum output voltage. Spark plug tester is just a dummy spark plug with a fixed electrode distance of 10 times the normal electrode distance. So if your spark plug have a distance 0.6 mm - should the spark plug tester have a distance of 6 mm between the center electrode and the side electrode. So the short and long of this story is, that you can easily have a spark between the electrodes in free air, but when the spark plug sits in the cylinder head, its a totally different story - then it´s under compression and the spark will be missing from a bad spark plug. I know, it became a little theoretical but i hope you understand what i´m trying to say.