I don't own a Yamaha 600 but do own a KLR 650. My bike started showing exactly the same symptom as yours about a year ago. I've spent a year stripping carbs, cleaning connectors and the like with the problems slowly getting worse. Finally a few weeks ago the bike refused to run - solution has eventually turned out to be a new CDI unit . With this fitted the bike suddenly runs hke new . Wish I'd bitten the bullet and spent the money on it Months ago.

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Martin

finally back on the road again


http://awayonmybike.blogspot.com/

I can echo that, my 86 XT that I purchased new got to be hard to start, ran poorly, back fired quite a bit. It was leaking oil all over the place so I started by removing the rocker box and resealing. I replaced all the rubber parts, cleaned the carbs throughly, replaced the seals in the carb slide lifter shaft plus gaskets and decal valve diaphragm. This process was all through the winter. When done I rolled it out and it refused to start, no spark at all. I pulled the cdi from my 84 that I purchased as a parts bike and it had no spark.

I then set down with the manual, OEM is best, and tested the ohms of the stator coils, ignition coil wires, grounding circuits etc. I used the AC volt setting on my volt meter and measured the trigger coils for output, they did have a kick when kicking over the engine, I checked the cdi charging coils for a kick and they did. I then compared all readings to the 84 and got very similar readings. I concluded it must be the CDI.

I knew I did not want to buy a used one that was probably old as the two I have so I ordered two of them from the guy in New Zealand. I waited and waited with no response and got to checking elsewhere.

I contacted Zeeltronic as I already had good experience with their CDI's on my Yamaha two strokes. Borut said he did not have a CDI for the XT but would look into it. He then made me one to try out. I think I got it just a short time after the New Zealand units showed up.

The Hyperpak unit was installed and the bike started right after a few quick kicks, idled perfectly.

When the Zeeltronic unit showed up I programmed it with a few small changes from stock, they do come ready to use but since I was already familiar and had the necessary programing cables and used the provide software I altered things a bit.

The Zeeltronic unit SEEMS to have more low end punch, I even swapped out the units after warming the bike and A B compared them back and forth. I still think the Zeeltronic has a bit more low end. Some have agreed with me some not.

So to end this long version story. These bike are getting some age on them and CDI's do age and fail.

Steve

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

hi guys and thanks for your replys , last friday i took the carb off the bike and cleaned the outside then stripped it down and put it in a friends ultrasonic cleaner i borrowed . the whole carb would not fit in and submurge so i had to keep revolving it around , 2 hours later and i reasembled it . i removed the intake rubbers and resealed them, then on with the carb . the bike started 3rd kick and runs well , i will post again in a few days to report back how things are going but it is starting ok, will have to take it for longer run to see if it still surges in the higher revs . it still pops a little on slow speed up changes ive reset the mixture screw to 2.5 turns out which i think is correct, before it was 3.5 turns out so it is now a little leaner . zigzag

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