Diagnosis please - '89 EX 570

C

Classic SRX

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Joined
Nov 30, 2004
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135
Age
47
Location
Halifax, NS
I was riding along at 1/4 to 1/3 throttle at about 60km/h - maybe 5000 RPM(clear day, just about freezing) and the sled quit on me. The plugs are a chocolate brown and it seems to have spark - at least when they are grounded on an engine stud - I can't be sure they're firing under compression. It seems to be getting fuel. I've tried priming with fuel through the plug hole - it'll kick, but won't start. I've got some spares parts that came with the sled, but I can't be sure they're good. From the spares, I replaced the external coil and the CDI box, but no change. The carbs are butterfly's from an '87 with stock jetting. I had put about 30km (20miles) on today before this happened and the sled was working fine.

My next step is to open it up and look at the stator. I've got two spares, but again, I can't be sure either is good.

Anyone have any other ideas? Or timing specs (I don't have my manual with me - it's on the missing list right now)? Any input is appreciated!

Angus
 

ANGUS, SOUNDS LIKE COIL ON STATOR. THOSE ARE VERY CHANGABLE AND CAN BE TESTED. I HAVE SPEC IF YA NEED IT. ALSO I AM SHURE VERY AVAILABLE FROM YAMAHA. 3:16 (yammie tony)
 
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Thanks Tony. Specs would be great if you've got 'em. I'm going to try the spare stators I've got today and see where that gets me.

A.
 
My uncle was good enough to do a stator swap for me over the weekend (sled is at home, and I'm 3 1/2 hrs away). He tried the two spare stators that I've got, and no luck getting it started. He also tried several combinations between the 3 stators and 2 CDI boxes.

Compression test is next on the agenda, but pulling it over, it feels plenty strong. Even if one side was bad, it should still run on one cyl. What's the chances of both going bad at once?

I've got a spare wiring harness to try next. My thought is if there is a broken wire or bad connector in the harness, I should get full fire or none at all shouldn't I?

Any more suggestions Tony?

A.
 
Well, I have some spark. If it was good spark, it should fire a few times on the fuel poured in through the plug hole shouldn't it? Sometimes I get one kick on the prime, and othertimes nothing at all. That's why I was wondering if the spark is too weak under compression.

I should also note that this was an elect start sled, but I removed the battery & starter in the fall (to shed some pounds). As far as I can tell, all the wiring at that end was properly tied off, but it's got me wondering now...

A.
 
YES I AGREE !! GOOD SPARK THAT SLED SHOULD FIRE WITH GAS POURED IN PLUG HOLE. YOU HAVE TO START THERE. I DOUBT ITS COMPRESSION WHERE THE MOTOR IS HURT. YOU GOT SOMETHING ELECTRICLY GOING ON. YOU REPLACE PLUG BOOTS AND OUTSIDE COIL ? YOU NEED TO PROBLEY CHECK ALL WIRING. MAKE SHURE THAT WIRING FROM THE ELECTRIC START AIN,T CAUSEING THIS. MIGHT HAVE HOT WIRE GROUNDING OUT YOUR INGINTION. MIGHT BE ACTING LIKE A SHORTED OUT SYSTEM. 3:16 (yammie tony)
 
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Yeah Tony, I swapped out the external coil - was one of the first things I did. I'll go through the wiring harness next.

A.
 
I sure will Tony. I'm not sure how much more testing my uncle will do for me (his young fella beat up one of their sleds the other night, so he's gotta get that up and running), so I've got to get home to look at it myself. Not sure if it will happen this weekend, but if not, it'll be next. I'll keep you in the loop! Thanks for the help.

Angus
 
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