DavidSS

Yes, I checked the wiring per your instructions and all the values were within tolerance. The spark appears to be a blue/yellow spark now. But if my memory serves me, last week it was more dull yellow. But that might have looked that way due to being outside in the sun. Where as last night I was in the garage and it was darker. And yes, I put in a new spark plug last night. And yes we tried push starting it until my sons were exhausted! But to no avail, it just is dead, not even a pop. It acts like the switch is off, but I know it is not. ... a side note... I took the new plug out last night after the exhaustive attempt to start it, and looked at it. It was damp with fuel, so I know for sure there is fuel getting into the cylendar. could it be a timing issue??? like for example the plug fires when the piston is in the down position. Like 180 deg out? Is that possible on 2-strokes? Just grasping at straws now. Should I measure how much voltage is getting put into the coil (orange wire). I can do this with a storage scope and high voltage probe. I'm an engineer and have resources However, are there any printed spec that will give me an idea as to what the voltage should be? I'm about ready to turn this bike into a boat anker!!

I know the kill switch is working correctly because I have tested it twice. Once electrically (meter) and also have ruled it out by having it on, and checking for spark, and then turn it off and verify that the spark is non-existent. However, it kind of has those symptoms so I can see how you could assume that.

@ oldgitonabike, Well I checked out all the wiring to the CDI and coil... it is all good, and within specs. This is just CRAZY! As a sanity check I scuffed up all the connection points with sand paper, and I bought a new plug, and checked the spark again. It seemed to be brighter. From what I can tell, it is sparking sometimes blue, sometimes a mix of blue/yellow. I made a small video of it. If i could figure out how to post it so you could see it, then perhaps you could tell me if it is acceptable. I can't believe that the CDI would be bad. I would think it either works completely, or it would be completely dead. Not just weak. After all, it is mainly just a capacitor in that black box, with a diode.

oldgitonabike, these are great instructions!! I will check the electrical out and get back to you. I'm going to owe you a million! I sure hope its something simple like fraid wires or bad grounding, because I don't know were I will find a new CDI for cheap..... stay tuned.

It might need a new coil. You can check the resistance of the coil with an Ohm meter, but I am not familiar with your model so can't say what resistance you should see, but I would guess somewhere around 3 to 5 ohms. Sometimes the coil wire can burn or break internally, so if you read an "open" circuit on the meter, this might be the problem. Could also be a short in your on/off switch, or a number of other electrical things.... start by checking the coil first and work your way back. Good luck. should clarify... that is the primary side of the coil. ON the secondary side, it is probably much higher resistance.. like 5K.

hello, just joined the club! I recently bought an old 97 yamaha DT175 as a project and currently working on it. trying to get it to run, over years I have owned several bikes. Honda, yamaha, suzuki, KTM, Husky. Only one street bike and that was a Honda 350 twin. Its been 15 yrs since I last has a bike, so this little yama will be a good starter. D

I did clean the entire carb with carb cleaner, and sprayed in every hole I could find. so item "A" is clear. I did poke a fine wire through the jet to unplug it, but I doubt I enlarged it.

I am fairly confident the "choke" is working. However, I did not take that section apart to clean. Looked like it is just a mechanical spring operated plunger and since it was doing its job I chose not to disassemble it. As for the rest of the carb, I used carb cleaner and sprayed in every hole I could find and made sure I saw a stream of fluid coming out of each end. I soaked all the disassembled parts (needle valve, pilot jet and main jet, and so on) in the cleaner. And yes.... I did use some small wire to clear the plug in the pilot jet, but was careful not to ream it out. Its clean!

thank you for the sanity check. As far as I can tell the choke works. If you can call that a choke. It doesn't really choke like a traditional "flap" type choke. I did a test the other day, where I took the spark plug out and made sure it was dry, then put it back in, and I kicked over the engine about a dozen times, with the fuel on, and with choke on. Then took the plug out again to see if it was still dry. It was just faintly wet. This was before I cleaned the carb (for the second time).... I can try this test again today, and see what the plug looks like. I have not replaced the plug, just cleaned and gapped it. Should I try a new plug? My common sense tells me it should work as is! When I tested the spark, (laid the plug on the side of the head fin and kicked over engine) I got good yellow looking spark from it. That should be OK to ignite the fuel right? Could there be a wiring problem that is keeping the engine from firing? Perhaps the magneto? Also, as a test, I moved the slide needle up from the 4th notch to the 5th, to see if leaning the fuel would make any difference. Obviously it did not, so will put it back to the factory 4th position. How about the 2-cycle oil? It just occured to me that I did not replace that, and who knows how old it is... would that make a difference?

Hello all. I'm new to this forum. I recently bought a project bike to restore. It had been sitting in a guys garage for 3 years! He said it ran fine before he stored it. Unfortunately, he left the gas in it! I figured I would be able to fix it fairly easy since I have worked on 2-strokes in the past and know them pretty well. Here is what I have done so far drained tank, refilled with good petrol removed the carb and completely cleaned it. checked all the holes and made sure it was clear. adjusted the float height, set the fuel mix valve. even checked the main needle. removed the spark plug and cleaned and gapped to .024 changed the crank oil. charged up the battery I figured it would start, after all that it will not. Not even a little. The bike is getting spark. It is getting fuel. What else could be wrong???? Could the 2-cycle oil pump be causing a problem? Perhaps it is too rich and it keeping the fuel from igniting? Could it have something to do with the CDI (capacitor or regulator system?) Any suggestions as to where I should look next? BTW, I looked at the intake reeds. From what I can tell they are OK. I don't know much about these and what they should look like. also, I sprayed some carb cleaner down into the cylinder, just before putting the plug back in. Kicked it over, and it actually started for about 2 seconds! It has not started since.... Even tried push starting it! HELP!