Pics of my piston failure
- Thread starter SRXChris
- Start date
either too low of octance,as you have detonation on all 3 or the carbs are really dirty, I would lean towards too lean/octane too low for the load on engine. See how the front edge of the piston is burned back that's the lean eroding the piston crown, once the ring is exposed to the flame front it turns orange/begins to melt and turns into the mess you have in the one cylinder with chunks and parts of piston being mashed into the head, goint into bottom of engine and ruining the crank bearings.
roudyroy1
Active member
exhaust side of the piston is rounded off from heat. id say lean, usually but for it to happen on all 3, that may be a fuel issue. when you pull the carbs apart, before you blow the jets out hold them up to the light and see if they are obstructed.
SRXChris
Member
So crank bearings will likely be shot? I hope not. if they are I will part it out as the price on those if I can find them would cause me to not rebuild. Still have not pulled clutch out to pull engine completely out. I have to do this soon to figure out what to do. Figured I'd post some pics here for some analysis to get some advice.
Carbs were allegedly cleaned but I didn't do it myself so I will take them apart and inspect.
Always ran Shell 91 fuel, non ethanol. Last few trips it received Ultramar 91. 91 is all I can get around here
Carbs were allegedly cleaned but I didn't do it myself so I will take them apart and inspect.
Always ran Shell 91 fuel, non ethanol. Last few trips it received Ultramar 91. 91 is all I can get around here
roudyroy1
Active member
did you limp it home or shut it right off? i have had some pretty nasty blow ups from snagging a ring, shut the engine off immediately, and have had good luck with flushing the bottom end out with diesel and a suction gun. after all the aluminum was out the crank did not have any rough spots, still running today. ideally you would want to split the cases and inspect, but that is up to you.
Another thing that comes to mind is fuel quality, is it a high volume station? because other than sleds, not many people are using 91 in the winter so it may have been sitting in that tank for awhile, just a thought.
Another thing that comes to mind is fuel quality, is it a high volume station? because other than sleds, not many people are using 91 in the winter so it may have been sitting in that tank for awhile, just a thought.
SRXChris
Member
Well you could say I limped it home. Was wide open on Limerick lake felt it bog and let off. It felt low on power but still ran good so I didn't think right away that was the issue, thought other things. As I came closer to staging area problem got very bad, backfiring etc but I could see truck and trailer so I continued on about 100 meters. Dragged it up trailer and dragged it off trailer.
Both service stations receive a fair share of volume but how much supreme they sell I have no clue.
Ordering a clutch puller this week and will remove rest of engine. Been thinking long and hard about this sled so will probably send block and crank off for a refurb and cry about the cost later
. There is a company out of Quebec called http://www.cvtech-aab.com/en/# and I keep hearing that's the place to send it to. They can split case, rebuild, true and install it.
Was going to split case myself and flush out but did't want to spend the money on a top end rebuild only to have bottom end take me out for something.
Both service stations receive a fair share of volume but how much supreme they sell I have no clue.
Ordering a clutch puller this week and will remove rest of engine. Been thinking long and hard about this sled so will probably send block and crank off for a refurb and cry about the cost later
. There is a company out of Quebec called http://www.cvtech-aab.com/en/# and I keep hearing that's the place to send it to. They can split case, rebuild, true and install it. Was going to split case myself and flush out but did't want to spend the money on a top end rebuild only to have bottom end take me out for something.
roudyroy1
Active member
Well you could say I limped it home. Was wide open on Limerick lake felt it bog and let off. It felt low on power but still ran good so I didn't think right away that was the issue, thought other things. As I came closer to staging area problem got very bad, backfiring etc but I could see truck and trailer so I continued on about 100 meters. Dragged it up trailer and dragged it off trailer.
Both service stations receive a fair share of volume but how much supreme they sell I have no clue.
Ordering a clutch puller this week and will remove rest of engine. Been thinking long and hard about this sled so will probably send block and crank off for a refurb and cry about the cost later
Was going to split case myself and flush out but did't want to spend the money on a top end rebuild only to have bottom end take me out for something.
I have sent cylinders away to CV-tech to have them re-platted, they did good work and stand by it.
take pics and mark all your stuff going to cv tec. i have gotten burned by them before on a crank for my brothers sled. supposed to be a guy in sountern on that does them too.
SRXChris
Member
Care to elaborate? You can PM if need be. I've now read a few complaints as well. There is another crank shop near Orillia that has good reviews and a few bad, so I guess roll the dice on that one.
Any idea or a name of the southern Ontario guy? Thanks.
roudyroy1
Active member
Give bondi engines a call in Ontario too
i will post it up for all to see.
sled was brother (kirkswim) 2002 sx viper with 6000km on the clock. lost a mag side connecting rod bearing on a ty ride on a long pull on the grade. sled was jetted on the rich side of safe according to piston wash and plugs. tore it down and sent them lower cases and crank to be repaired. 3 weeks after we sent it he called as he had not been contacted yet. they told him the whole thing was scrap. he told them to ship it all to him. when he got it, they had repaired the lower case but had stolen the good centre rod section from the crank and shipped us the rest back. would not take his calls or give him credit for centre rod section. he eventually got another good crank from another ty member to get the sled going but i tell anyone going to cv tec because of this.
SRXChris
Member
Thanks for letting me know. Not sure who to use now also was recommended Iantomasi as another reputable builder.
SRXChris
Member
Received clutch puller tonight after work, popped it off and now will pull rest of engine out Saturday when I have a few hours.
SRXChris
Member
I have this motor torn right down now and have found a few issues. First I'll ask about the oil pump cable, supposed to be a 22 mm gap but this looks way off from that, as well as cable pulling out of housing is normal?
When cable was on pump i pushed throttle in and when was wide open as far as I could tell pump was as well.
Cable is obsolete from Yamaha, is there an aftermarket one that works or another model that fits?
When cable was on pump i pushed throttle in and when was wide open as far as I could tell pump was as well.
Cable is obsolete from Yamaha, is there an aftermarket one that works or another model that fits?
apex/viper rider
Member
you can still get cables from yamaha i just bought a 2003 viper mountain cable aftermarket cables are harder too set up and its normal that the cable pulls ot thats how you measure the 22mm setting
SRXChris
Member
Carbs as I figured were spotless. They were just cleaned. Leaning towards a crank seal for engine failure or as Mr Viper said low octane gas. Engine bay is a complete mess of old oil and grease and inside recoil housing was the same.
If you had a choice of gas would you run 91 no ethanol octane or 94 octane with ethanol?
If you had a choice of gas would you run 91 no ethanol octane or 94 octane with ethanol?