I have problems (please read and help if you can)

excited_kyle

New member
Joined
Dec 24, 2003
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5
Location
Saskatchewan
Ok... so i have a 1990 Exciter 570. I am 16 years old. It is my first sled. I bought it myself. It doesn't run most of the time....

Me and my dad are trying to get it running. Its only got 2200 kms on it, its got pipes, different clutch weights, better skis + track, custom paint, pyrometers, and aftermarket hand warmers. It doesn't have electric start.

It seems to be an electrical problem. My dad test drove it, it ran fine. We get it home, fire it up, and it doesn't run worth ****. When it does run, it barely idles, and only on the right cylinder. Nothing happens in the left cylinder until it reaches about 3500 rpm, at which point it backfires through the pipe, and perks right up.

At first, we just changed the plugs, and check the carbs (which are clean). Same thing. So we pull the plugs and look at the sparks. When I was pulling the string, my dad could literally hold on to them and not feel a thing. It seems that there is only spark sometimes. At this point, we figured it was purely an electrical problem. Yamaha tells us that it is most likely the primary stator coil. So we replaced that. Same thing, intermittent spark, poor idling, etc.

So then my dad + my dad's boss (the previous owner) figure it must be the ignition coil. I took that off and got it tested, and it turns out it was very slight bit weak, but not enough to even consider there being a problem. Plug boots are fine, wires are fine also. Ok, so it must be the CDI, the last component of the ignition we say. I go and get a new CDI, and put it on, and the same thing still happens.

So I say to hell with you exciter, I will drive you. Since it runs good after you get past idling. I get about 4kms from home, on the lake, and at about 100 km/h I let off the throttle, not realizing it would die since it can't really idle. But it died. So i coast to a stop, and think, "that's ok, its done this before. just pull the string a few times to get her running again and we'll head home." NOT THE CASE. Ever since it died, it won't run anymore. AT ALL. It tries to fire, but after about 6 or 7 pops from the right cyl. it dies. The left cyl. still doesn't fire at all. I can't keep it running with the choke, the throttle, choke + throttle, no choke + no throttle, or anything.

Sorry for the long story, but what do you think is wrong??? Is there anything else electrical that could be not working? TORS? Keep in mind that there is barely any spark when you pull the string... So we don't think it is carburateur/fuel related.

Any info would be greatly appreciated.
 

Compression?

Check the compression in both cylinders. If both do mot have the same compression then you have a bad piston/rings. Also check your stator,unplug the tors wires from your carbs and take the 2 wires that come from your wiring harness and plug them together to complete the circuit. Those are the only other things I can think of to check for..Good Luck
 
I had a 87 exciter that had many problems and this could be one of them , I had bad inlet needles that would flood the carbs and act like it was the igntion....then after you got her going it would clean out....also check the pilots...drain the gas out of the tank and system and really clean them carbs....
 
Thanks for the replies. We are going to try and pull both carbs off tommorrow and check them over. I just need some ideas as to what would be causing this. Do you guys think the TORS could be my problem? It seems like it has a very weak spark, which is why it only fires on one cyl. when @ low rpms... but this could also very easily be carb related...
 
tors

its not the tors, i've had problems with that and the tors just cuts you out after trying to accellerate from at stop and thats once in awhile. Check if your pistons are bad and check compression.
 
weak spark

make sure you check your plugs, that they are the ones required. Also, see if you have a grounding problem maybe something is arcing across and killing your electrics, bare wire somewhere. Best way to find this is disco the light, run it outside in the dark, or at least have someone pull the rope while you stick your head down. Another thing you can do is take it to a dealer and have him check the coils with a multimeter. If you frig around with it all winter, you may run out of snow. Spend the 40.00 for diagnosis (if he finds something), remember its very hard to diagnose something over the phone, or intermet, much easier it someone that know what he is doing can crawl around it.
 
check the spark with brand new plugs. If you have carb problems you may be fouling the plug then you check spark and it does not spark properly. If it ran ok at higher RPM it sounds like carb needle problems.
You need to check compression and make sure both are the same. An air leak in the crank can also cause these type of symptoms.
Good luck and post your findings.
 
Have you checked the internal ignition coils? We had a similar problem with a 540 once. Ended up being either the pulsar or internal ignition coil. We never pin pointed which one it was because we switched the entire stator. But that did the trick. Believe me, we went through all the stuff you have done before figuring it out.
 
We talked to an engineer from Yamaha a couple of years ago regarding my Dad's old 92 Exciter, and he said the Carbs on the Exciters were junk. So we sold it. We tried everything before that, and nothing changed... If anything it got worse. We unloaded it for half what we paid for it. They can be a bit of trouble to figure out. Good luck.
 
If the sled has waste spark (both plugs fire at the same time) swap the spark plug wires. You said only the right cylinder was working and the left would come on at ~3500rpm...If the problem "switches cylinders" with the wires swapped it's in the ignition somewhere...If it doesn't, then it's probably in the carbs.

MJB
 
ok... so it turns out the spark problem was the ignition coil. I got that replaced, and it has beautiful white/blue sparks now. I also bypassed the TORS system (just in case). But the problem is still there, it just has gotten weirder.

I cleaned the carbs once, start it up, still won't idle on the left, still runs 3500+ decently.

I pull and clean the carbs again. Start it up, starts hitting on both cyl.'s at idle, the right exhaust temp ran at about 350 deg., the left ran about 500. So i think, oh good, problem is getting better. I take it for a test run and get about 100 yds, and the right cyl drops right off, as if i just took the piston right out of there. It wouldn't barely stay running without a lot of extra help from the throttle. I could get it to about 3900-4000 rpms, (the clutch engages 4000-4100) but it would bog right down and i couldn't get it to move, and the right cyl wouldn't try to fire, the exhaust temp went right to 0.

Since then i towed it home (from all of 100 yds away), and cleaned the carbs (YET AGAIN), and i can't seem to even get it started (by myself, it has always been a 2 person job). So i have to wait till my dad gets home again to see if we can get it running. But i have a strange feeling it will still have problems.

So wtf??? Does anyone have any input on what this could be? I have run out of ideas and so has my dad.
 
jetting

you may have an air leak, what jets are you running?
 
had a sled that did the same thing only run good at high RPM. Was the crank seals.
once you get it running again, put it up on a stand, spray some WD-40 behind your primary clutch, do this at different RPM it may not have enough suction at idle. if seal is bad it will suck in the WD-40 and surge.
Also do this on the mag side, with engine running spray down behind the pull starter, or if there is an inspection hole for the mag?

you have to try it at all RPM settings. had a buddy his sled would run great on the stand but once he took it out he kept melting down a piston. Found out it was crank seals. Idle it was good at higher RPM it sucked in more air and leaned out.

Hope you get it figured out, and can get some real riding in.
 
I would do a leakdown test to make sure all the crank seals are good. I had an old 440 that worked good until it warmed up and then one cylinder would crap. Turned out to be a seal. I would also double check the wiring harnesses to make sure there isn't something going to ground. Also, see if you still have good spark now. The fact that the spark was not good before makes me wonder if there is something that goes to ground intermittently.

I had a 92 that I sold with 7500KMS on it. It was aways good to me.
 
Lots of good advice going on here so I"ll add mine. What did your carb cleaning include? Were parts soaked in carb cleaner (not the spray, the type that eats rubber parts and removes paint, 3 gal can about $40 at NAPA). Were pilot jets and emullsion tubes removed? Pluged pilots will cause lean condition at idle. Varnish in tubes keeps fuel from atomizing properly. Tubes can look fine and still be a problem. BTY if Exciter carbs are junk then almost all Cats, Doos and Poos have junk carbs too! Think they"ll admit that! LOL
Good Luck , Tim
 
I am going with crank seals also.My friend had an exciter with the exact same conditions you are talking about(except the spark).The wd-40 or starting fluid test worked for us also.Don't wait to long or your asking for trouble.We have seen a few of those exciters even runnung with the bottom of the piston skirt broke off!!Even ran pretty good amazingly.Compression needs to be checked after the seals are for accurate readings.good luck. :wink:
 
Thanks for all the great help guys... It is actually just about running perfectly now. The compression is good and it wasn't an air leak. The carbs were out of tune, the throttle cables were mis-adjusted and the coil was bad (which led to bad plugs, which was also part of the problem).

But we have sorted out all of those problems and now it should run good... forever... i hope... (lol). All it needs now is some slight tuning.

Thanks again.
 
this may be way out of line but i had a 89 exciter and had similar problems.what it was a squirrel had put some acorns in the air box and from time to time one would roll into the carb and the needle wouldn't seat
 
Thanks for the replies...

I do have a couple of questions actually. What kind of horespower do you estimate i am putting out? My dad (being an avid snowmobiler of the early 80's) thinks about 100hp, considering only upgrade is pipes. What is an exciter, just a higher powered liquid cooled phazer??? Where did the exciter come from? and go to? Actually any model information would be great, i can't find anything on the internet.
 


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