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Discussion Starter #1
I've got a 93 exciter SX that we just can't get running right.
problems include:
- fowling plugs (within a hour or so after replacing them)
- runs like choke is on

sled history:
Three years ago scored a piston, local sled shop sleeved it (this is when most of my problems started). Since then the carbs have been cleaned, synchronized, needle/seeds replaced, choke cable adjusted, oil injector cable adjusted. Compression is equal on both jugs at approx 130psi.

So what should I look at next?
clutch? replaced it approx 5 yrs ago with a comet 108c
Ignition? What do I test and how do I test it?

Being that it is the SX are there any major differences that I should be concerned with verses a regular exciter II?

Any ideas would be greatly appreciated
 

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Sounds like you are already saying its running rich, If its fouling plugs and runs like the choke is on, that says a rich condition. So does it clean up when you ride..Like if you are crusing at 1/2 throttle does it run good? does it smoke alot when idling? When you foul a plugs is it the same one, both at the same time? From what you are saying its a fuel problem, Start bak at the carbs, are the floats adjusted right...this would cause a "flooding affect" ...
 

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Discussion Starter #4
3ft and RR-skier, Thanks for the response and interest in my problems. I guess I should clarify that the machine runs good initially, once new plugs are put in. Then it varies from 15min to a couple hours when she dies. I had a guy from Milwaukee who raced yamaha synch the carbs and he set the jets and floats to standard setting. Also, I put a new fuel pump in. From what I understand, they did not oversize the piston. With that said, I guess that's why I was turning to other possible problems other than "fuel."
 

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I wonder if the oil pump might be the issue. Set to factory spec it might still be providing to much oil. Can the machine be run with premix? Does any one know, how to do?
 

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Ok, That helps....If you are able to run it for an hour or 2 you should be able to tell us if it has excess oil compsumption...If thats the case do not ride it, to much oil will cause a lean condition and you may end up with bigger troubles. To me if it runs for 15 min. to an hour or 2 and then fouls the plugs........(what do the old plugs look like when you pull them, oil soaked? or what color, are they wet? This time issue has me thinking...As that motor warms up, something is changing........Where do you have your needles set? (position of clip). I have heard of sleds, that as the motor warms up the stator starts to fail, and causes a weak spark...maybe fouling out the plug. I really don't know, Thats a tough one to help with. I'll try and keep throwing ideas at you. later 3ft
 

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The ignition coil may be bad on the magneto. You can test these by checking the resistance values. I don't have my Exciter manual right now but maybe the dealer could help.
 

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Discussion Starter #8
The wife and kids are gone this weekend, so I'm hoping to get a little work done on the sled. KevinEX570 I found my manual last night so hopefully I can start testing some of the electrical possibilities.
Also while digging around I found some of the old receipts from the shop that did the engine work. One thing I had noted there, but forgot to mention was...the gas mileage drastically changed after the piston was fixed. It went from 17mpg to 7mpg. And I think this is why we were so sure it was some type of fuel related problem (that's not to say there could be multiple problems).
Thanks
skiwater
 

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from what your saying about the gas mileage diff , deffinately check your choke cables this model of yamaha is very well known for it. just lift your hood and pull agressively on your cables where they go in the carbs. dont be scared to pull,you wont break'em. good luck
 
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