big big problems

bluelightning

bluelightning

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Joined
Nov 15, 2005
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151
Age
40
Location
bristol CT
hey all,
just arrived back home from a weekend of snowmobiling up in pittsburg new hampshire. was expecting the time of my life, until i ended up having to ride a polaris 550 air cooled rental :(

when we arrived and unloaded, we were just puttin around the lake a bit waiting for everyone else to get ready (our cabin was right on the lake it was sweet). after zippin around for about 20 minutes, i lined up with my buddy on his mxz670. we ran back and forth a few times, and on the last run, WOT the rpms dropped to 7500 and was makin a bogging noise, let off the gas and it died........tryed to start it and the pull cord would not budge. walked away fed up throwing a tantrum like a little baby back to the cabin, and one of my buddies went to see what i was talkin about and wham, started right up for him! and it was runnin fine also. figured i would zip it around a bit more to make sure there were no further problems. ended up doing it again, with the same result. dropped to 7500 rpm, dies when i let off the gas, when i went to pull it it wouldnt budge, but if i pulled it very slowly through one rotation, i could then start it up fine!

then here comes the good part. was ridin on the trail, and she started coughin and bogging, sounded like a fouled plug. left it running, pulling one wire at a time so i could tell which cylinder the problem was on, and i narrowed it down to the mag side. changed all the plugs anyway and tryed firing her up. started up fine, but was still only runnin on 2. yamaha dealer was only a few miles down the road, so i decided to limp it down. tech came out and took the plug out, put his thumb over the hole as i pulled it over, and he proceded to tell me "you're f*cked" out of curiosity when i got back to the cabin, i tryed this out, as no one had a compression tester. the mag side pulled much weaker than the other 2.

was just serviced professionally 2 weeks ago, cleaned and adjusted carbs and power valves, tuned my clutch and new track. was running like a raped ape in the snow we got around here last week.

what happened? and what caused it to happen? any ideas would be great


needless to say, it really sucked riding a rental all weekend :(
 

I bet you talked to darrin at pittsburg motorsports. he is a great guy. if it was runing a little too good it may have been lean. have you jetted it at all?
 
Dude, that sucks :(

If those jets are stock, and those carbs have no crap in the bowl (which we know they don't, right ;)! ) Then it must have sucked some air in somewhere, crank seal, intake boot, maybe even the crankcase seal. Sounds like the Mag side had a lean burn down. It may not have been good that you ran it after your buddy re-started it the first time, it was seized when you couldn't pull the rope. At least thats my hundreds of miles away diagnosis.

Anybody else???

Just had a thought, is there any elevation issues between home and that riding area??? One alot higher or lower than the other??
 
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Mine was the same man!! mine Seized, couldn't pull her over.. but went to go get my dads towing sled, I tried it and it pulled over... whats the deal with that????
 
auji700triple said:
Mine was the same man!! mine Seized, couldn't pull her over.. but went to go get my dads towing sled, I tried it and it pulled over... whats the deal with that????
Click to expand...

Piston gets so hot it expands and freezes (siezees) in the cylinder. When you let it cool down long enough, the piston returns to 'normal' and frees up in the cylinder.
 
I agree with crewchief.
Some kind of lean condition...or....how long did you let the machine warm up before you ripped around the lake...possible cold seizure.
 
i was on it all day! it shouldn't have happend..... BUT!!!!!! Before it happend the DCS Light Came on, and on and on.. then Blew some spark plugs, replaced them and then i got up the trail, seen ALOT of SPARKS, shut it off and seized.... i had to walk home, when i got back to it, i pulled it over and success. but everytime i tried and pull it over it got harder and harder, and eventrully seize again.

does it do damage.....!!!??
 
well if that happened the first time, and then i started it and continued to run it, how would that have caused more damage? didnt the damage already occur when the problem first happened?

carbs were cleaned by me, but i then had it serviced profesionally just to be sure i was 100% before this trip. sled has 2800 miles on it (but speedo wasnt working when i bought it. i let it warm up for a while before unloading it off the trailer, and before goin WOT across the lake i was just putting around for about 15 minutes waitin for everyone else to suit up. i haven't done any jetting in it, but when i had it serviced i was told the jets were stock.

i dont know as much as u guys do, but if it was seized, then why did it start right back up? and why was i able to get it back to the cabin with almost no problem? I also started it up to load it into the trailer, and then again to unload it when i got home. the funny part is, it was starting up first pull both times lol.

but yea, the problem is definately a lack of compression on the mag side. haven't been able to throw a compression tester on it, but ill do that later today. what are some opinions of what my best/worst case scenario can be here? i mean, if its still running, it can't be THAT bad right?
 
id just pull the cylinders and take a look when you get it home. not telling why. do you have the correct pistons and rings sizes in it? are you running oem yamaha pistons? if its not cold seizing, somebody could have sabatoged your sled with something that makes engines stick. just looking at all possibilites why its seizing shortly after a few runs
 
when my 600srx was toasted,totally screwed mag cyl-i mean zero compression,it started on the first pull and was able to reach ~75mph on the way home(not clever i know but i was pissed,first ride on a week long trip to the mountains and the f*cker does this to me)so i guess it can run even though it is F.U.B.A.R-i tell ya the rev550gtx i rented was NOT as fun.....i hope that this is not the case for you though-everyone cant have my bad luck! ;)!
 
This is just a maybe, but I saw a tripple pol do this once. He found some ice in the carb on the bad jug. Maxdlx
 
tom, bought it used so im not really sure what i've got in there. guess i'll just have to pull the heads and take a look. is that the easiest way to look at the pistons and cylinders? just pull the heads?

zap, same thing here, what ended up being wrong with yours? i would have killed for one of those 550 rev's. my polaris 550 classic was a DOG
 
i THINK i had a coolantleak,the orings between cyl and head,the whole time since i bought the slead(2 years and ~1500 miles ago)i have seen a little coolant seeping from the mag cylinder-not much,i added maybe 0,5 litre under the last two seasons.when it went i didnt take the time to let it warm up properly(like i always use to do other times)just ripped it off the trailer and raced to the top of the closest mountain-near the top i thought it was not pulling like i should(only 7500rpm)and it sounded like the chain or track was ratcheting(shoulda known right then i was f*cked),tensioned the track at the top and went downhill-the piece of cra-sorry sled wouldnt pull the rpm:s even downhill-stopped,took the plugs out and did the poor mans compressioncheck(thumb in the hole)and sure enough,no comp on the mag cyl.
at home i could see the damage more in detail,the piston was junk-could see the upper ring around the front,cylinder was junk too and the head was smashed by the debris flying around when i drove to the cabin,never seized though.
luckily i got a hold of a used complete engine,so i did not have to disassemble and check the crank e.t.c so its up and running better than ever.
needless to say im looking wery closely for leaks and im letting the sled warm properly nowadays....

as for the rev-for a fancooled 550 it was quite "snappy",up to 50mph anyway,the riding position and detatchable seat was nice but come on-i want to have FUN when im sledding,if i wanted transportation only i could just as well take the bus.... :yam:
 
I saw the exact same thing happen to a 99 mach z one time. We were running in warm temperatures and he didnt have his vents open. After we let it cool down and opened the vents he didnt have a problem.
 
actually i had the same thing happen to me this weekend, i was goin about 140km/hr and then the power dropped and then pulled off the ice onto the land and the thing was misfiring, and idling about 1400rpm. figured a ring was the problem, took carbs off and found out that the mag side carb was frozen solid .how hard is it to fix a cyclinder and piston, and put new rings on. what would be the process of takin the cyclinder apart to check the damage? also any torque specs of this and would the yamaha service book have all this info in it?>


thanks
JP
 
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