hi guys the problem has returned big time , i set of last night 5 o clock called for petrol all was well , called at mates house only few minites took 4 kicks to start , 2 miles in to ride on strieght road doing 30/40 mph bike dies starts then dies completly . tryed for 5 mins to start only got nothing then a spit out of the exhourst then dead . called a mate with a van to rescue me. at home no spark , diconneced black/white wire from cdi (thanks steveloomis) got weak spark hooked it back up no spark disconeced kill switch wirers weak spark hooked them back up still weak spark ? . tryed for two hours no spark/weak spark. up at 10am cleaning connecters weak spark no spark sometimes nice blue spark, but no run . after cleaning carb last week bike pulled good and strong i now think this was dirt in the carb and not related to bad starting i was having . still removed carb to check/ blow through with air line . started to check connections under tank there was a 4 way black crimped joint seemed iffy so made new connection with good bullet connecters tryed to start bike, 4 kicks it ran but would only idle/ tick over any revs and it started to die put timing light on to see if i could see misfire but very hard to see bike ran 2/3 min then died did this 3 times on idle sounds perfect , changed a few more connecters no run and very weak yellowish spark , tested coil on workshop coil tester all good have i got a bad cdi or still a bad connection ? can get cdi £100 ish from wemoto anone had 1 any good

hi guys a bit more info the bike is a xt600 49r american inport the cdi has 11 wires 2 of the wires are red and brown but thay do not connect red to red etc , they connect red to brown and brown to red they have always been like that 18000 miles ive done on the bike i tryed putting them right way round but loose spark completly ? just checked and a company in belgium does a 49r cdi but they are on holiday until the 23rd august . ive dealt with them before and they are first rate very fast delivery etc . so if i have to get a new cdi do i go red to red or red to brown zigzag

My USA model 1986 year is a 49 also. If memory serves, the wires coming out to the stator were the wrong color but did have the correct color little sleeves that match the color code. Does yours have the sleeves? My 84 wires were correct and no sleeves.

From experience it is quite possible your CDI is intermittent and dying. The only other thing I would do is take an AC volt meter set for about 20 volts AC or so, unplug the cdi charge wires from the stator and the trigger wires. There are 2 triggers, hi speed and lo speed. connect the volt meter to the wires, not wires and ground. Have someone kick over quickly and see if you see a voltage jump upscale. Remove the spark plug to make it easier to kick. Kill wires won't matter as they kill the CDI not the coils. You should see an AC voltage kick on both trigger coils as well. If memory serves there are 3 wires from the trigger coils. One should be between the coils and the others at each end of the coils, check one coil at a time.

If you get a healthy AC voltage kick on all coils then the CDI is most likely at fault. Both of mine were. The weak spark is the clue. I've heard good things about the folks from Belgium, go for it...

Healthy voltage kick is decidedly up scale, not just a slight flicker. You can use a digital volt meter but it is a bit harder to see the kick but it should show you that voltage is being generated. Ohm checks are good as well but if you get a good ac voltage upswing the coils are probably OK. Do you have the correct schematic/wiring diagram?

steve

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'84 XT600 is now bored to 2nd oversize and new OEM pistons and rings installed. No more smoking.

hi steveloomis i have a clymer manual the wiring diagram seems to relate to my bike , there are varies ohms meter readings which i hope to do tomorrow night although the manual says the engine has to be warm or the casing has to be warmed up with a hair drier , i will try doing them with no hair dryer . i have 4 wirers from the genarator 2 white go to regulator rectifier 1 red 1 brown source coil i think ( the crossed wirers ) to cdi , from pickups 1 white/red, 1 green, 1 white/green . do i connect the meter to red brown and kick and read scale do i test the white wirers, also the pickup wirers do i test them in random pairs or a set way , all your help is great thank you so much for your time , cdi ignitions are not my great love . thanks again zigzag

Ignore the 2 white wires, this is for charging the battery only.

The red and brown wires are the cdi charging coils. Measure those wires directly to your ac volt meter. Make sure you are on the AC voltage measurement mode. My 86 has small sleeves that are red and brown on the appropriate wire. My 84 actually has the correct color wire coming out of the stator.

The trigger coils are white w/green stripe and white w/red stripe then a green wire. The Clymer manual is wrong in measuring the OHMs. Measure the ac voltage across the white/green stripe and green then measure the white/red stripe and green. The green is common between the two white/strip wires. I think the Clymer has you measure across the white/red and white/green and gives the wrong ohm value. After I found that and wasted lots of time, I parked the Clymer manual on the shelf and got an OEM yamaha manual. MUCH better and accurate.

This should be all you need to check the output of the coils. If you need more info, just ask.

Steve

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'84 XT600 is now bored to 2nd oversize and new OEM pistons and rings installed. No more smoking.

hi there steveloomis ive checked the ac volts out of the sorce coil red and black wirers , ive got a analoge meter had to set it to 50 ac volts no 20 , kick and a good deflection of the neddle 3/4 of the scale, got 16ish ac volts on digital meter i tryed the pick up coils and no reading at all on either coil , i still have a weak yellowish spark sometimes blue , i put my digital ohms meter on the wires the clayma manual says to use the r100 scale looked on google to convert to digital meter , not sure i got this right ( going to re test with a friends expensive fluke tester) got sorce coil 140/150 ohms , pick up coil tested your way 12 ohms could be 120 ohms could not figuer out decimal piont ,will get a true reading on fluke tester, but main thing no ac volts, going to take off stator and clean it up . can the stator be rewound , does any body make them do you know or would i have to get second hand, thanks again for your help . zigzag

Well this is interesting. Try a much lower scale for the trigger coil ac reading. It won't be as much as the CDI power coils. If you are getting a spark at all then the trigger must be working. It has been a while since I checked mine so I don't remember how much kick I got, but it was certainly noticeable. It would be very handy if you could borrow a CDI and test.

I went back to my OEM manual. It is both correct and incorrect. Earlier in the manual where they show you where to measure the ohms of the pickup coil it shows in the picture to measure across the whole coil. In other words it is showing the meter connected to the white/red and white/green wires and indicates 110 ohms +-18%, in the back in the specs pages it indicates 110 ohms +-18% across white/red and green then 110 ohms +-18% white/green and green as I told you.

When a reading is given, that is the actual reading and has nothing to do with the scale setting on your meter. Scale setting is just for readability. An analog meter is easier to read if the max scale is somewhat close to the reading for most accuracy. A digital meter should be set as close as you can to the reading so the decimal points make sense. 18.0 volts is not as accurate as 18.091 volts, however, in this case we are not looking for a value of ac volts, just a kick and about how much.


Thanks for the update.

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'84 XT600 is now bored to 2nd oversize and new OEM pistons and rings installed. No more smoking.