Just can't win!!!

Y

yami1

Member
Joined
Jan 19, 2010
Messages
361
Age
55
Location
western ny
Well the fixer upper left me stranded in the woods again!!!! This sled is like christine for christ sake. Went for a little ride last night and thing was running great. was heading down what we call truck trail (road in statelands) when all the sudden she burped ,missed alittle,lost power. Still ran and not bad for two cylinders. New what happened right away so tried getting it to road. Had to negotiate a rock and a gate so had to get off and wiggle sled around. Sled quit of course. Got fired up moved went to grab helmet and quit again. This time cant pull rope out.Pull plugs mag side cylinder. OOHHHH BOY!! Anyway was like a mile walk out to road. Father in law came n got me got a trailer used a buddies sled and got her out. Haven't totally dug in to it yet. Did get exhaust pipe off .The exhaust on that cylinder is almost chalk white. I wasnt wide open. Hell lucky if half throttle. The only thing i can think is it leaned out. I will get some pics to you guys when I get home and start wrenchin again. Last winter did a plug check and all was good. Cleaned carbs last winter to. Did not do this year only because I rode it once last year drained the gas upon storage and used the atf fogging technique. So I dont know guess i shoulda checked them out anyway. Find out more when I open her up.
 
Keep in mind this is only my opinion. With todays fuel riding your sled with out at least looking inside carbs recently its not a matter of if but when its going to burn down. I half a$$ cleaned carbs last year on the girlfreinds sled.......Burnt down! If you skip everything else (bearings/hyfax/lubing chassis) Clean them carbs!
 
Yeah for sure sucks. Only consolation is everybody and there brother will be out tearing it up this weekend and trails arent that great yet. Were alot of wet spots and still need more snow. Just didnt want to sink much more money in it. Hopefully not much damage inside and can get away with piston rings. My luck is never that good so doubt that be the case
 
Thanks stagg sorry for the wrong area. So been doing some research and want some opinions. Again havent got inside this motor yet but thinking if its apart maybe should change all three pistons and rings. Im usually a oem guy also but see the wiseco kit comes with everything for a decent price. Anyone out there use them and have any opinions.
 
I use them in my 780 because thats the only choice. lots of guys dont like them, they work fine for me but they must be warmed up fully before riding every time you get on the sled. no shortcuts here or you will cold seize.
 
X2 on the warm up or cold seize. When I tore down the SxR 700 mentioned earleir I found it was only the center cylinder/jug was affected. Prolly would have ben fine to re-use cylinder but me and prolly dont get along so good! Had AMAZING luck as local sled salvage yard had a cylinder/piston that was as good or in better shape than the other 2 on my sled for $150. With a new wrist pin bearing,gaskets, a tube a yama bond and a gallon of antifreeze sled was back together for less than $300. Tear into it might not be as bad as ya think
 
yeah thats what im hoping for. but like you and probably, me and luck dont go together. Heading out of work now to go home and look into it. Get pics up asap. warm up shouldnt be a problem takes me forever to get all my stuff on. How long is long warmup 5 min.???
 
yami1 said:
yeah thats what im hoping for. but like you and probably, me and luck dont go together. Heading out of work now to go home and look into it. Get pics up asap. warm up shouldnt be a problem takes me forever to get all my stuff on. How long is long warmup 5 min.???
Click to expand...

Will vary by how cold it is out. With oem I wait untill I can feel warmth in xchangers. With aftermarkets I wait for them to get a little warmer.
 
IMG_20121228_223809.jpg
here is piston, looks to me like it got to hot. which confuses me cause it had coolant in system. Had hell of a time getting jug off to. also cant get wrist pin out. tryed heating up with heat gun but no luck. also tried to make a puller per service manual. any sugestions??? sprayed it up with some pb blaster and am letting soak. look like it got hot to you guys
 
Can't tell for sure but it looks like debris got in that cylinder. Question is before the seizure or after. I see a possible ring land failure. I am leaning toward debris before the seizure.

Can you post better pics of all sides including bottom side of piston above the wrist pin? Also the cylinder itself.

On the wrist pin you did of course pull the circlips, right? Do you have a piston pin puller? If not just use a bolt and some thick washers. I would replace the wrist pin, bearing, and piston of course. You will want to be sure to check the other pistons, etc. Make sure the case is cleaned out good.
 
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Looks like my Cat did 2 years ago. Check your boots between carbs and motor. They could be cracked and letting air in after the fuel/air mixture takes place causing a lean situation, which will cause you to burn down every time. I check this before every ride now. BUMMER MAN!!!
 
yeah pulled the clips. and did what you said with bolt and washers. tempted to put impact to it but dont want pieces of piston everywhere. getting more pics up here in a min.
 
Pics is a little fuzzy on my screen where it needs to be clear but. Looks like wrist pin clip is still in place? I would be interested in seeing top of piston as well as tops of other 2. Coolant doesnt cool the entire engine. Fuel/oil cools as well or at least carrys heat out of engine/cylinders. IMO that cylinder looks very similar to my burndown, my damage was worse on exhaust side of piston. If fuel delivery to that cylinder was down by 50% or more this would be just what I would expect to see. Pics of tops of pistons would be more conclusive but my opinion this falls under "lean burn down" Which main possible causes are dirty carbs,leaking carb boot/reed, or crankcase seals. Getting that piston off with out mucking up the rod will be key in lower budget repair. Finishing dismantling motor, split the cases (you can bet some of those chunks went down there) Give the crank a good looking over. At this point you should have a good feel for what its gonna cost to get this red head back up to snuff. The last few winters has gotten ALOT of people bailing on the sport. I have seen rideable redhead sleds listed for a few bucks more than I have seen engines listed for.
 
IMG_20121228_210552.jpg
other pistons. pto side looks ok but the middle one looks lean to me. opinions??? Has stock jetting. also forgot to add that it only had one layer on head gasket. Little thin for me.
 
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