Top end done after 4 rides!

[moyiesledhead]

My nephew's M1000, so I can't answer the obvious questions. Says EGT's never got over 1100F...usually under 1000F, and the plugs look fine. I'm leaning towards maybe airlocked & not oiling that side after the rebuild, but gonna try to go up and see it in person the end of the week.

 

[E to the v]

That blows wang

 

[Modman]

My nephew's M1000, so I can't answer the obvious questions. Says EGT's never got over 1100F...usually under 1000F, and the plugs look fine. I'm leaning towards maybe airlocked & not oiling that side after the rebuild, but gonna try to go up and see it in person the end of the week.

clean side looks like it was getting oil (no scuffing?), if the pump was air locked neither side would get oil and it would not have lasted 4 rides, not even one ride. Is it melted or grenaded? Air leak could have melted the left piston but it looks like some serious abuse to the left piston, wrong size pistons snapped a skirt off and then beat it up in the case?

 

[slomo]

the oil injectors have been known to fall out of the reed boots on these, as well as the skirts breaking off

 

[island rider]

I would like to see what the crank looks like , thats what my piston looked like after the crank seal went on the pto side , That sucks after 4 rides .

 

[moyiesledhead]

I would like to see what the crank looks like , thats what my piston looked like after the crank seal went on the pto side , That sucks after 4 rides .

Me too. Hope to be able to do that Friday. Crank seals were new. Could still be a bad one though.

the oil injectors have been known to fall out of the reed boots on these, as well as the skirts breaking off

Hoping he would have noticed that tearing it down, but I'll mention it. Yup, I've heard of the skirt issue before.

 

[moyiesledhead]

Is it melted or grenaded?

I can't tell from the pic either. The pic is all I have right now.

 

[moyiesledhead]

OK....no signs of heat to the top of the piston. Says he was sitting at idle on the trail waiting for his buddys to catch up when it let go. I'm now leaning towards a simple piston skirt failure. Any thoughts?

 

[Modman]

OK....no signs of heat to the top of the piston. Says he was sitting at idle on the trail waiting for his buddys to catch up when it let go. I'm now leaning towards a simple piston skirt failure. Any thoughts?

Need whole motor and do a pressure test on the case. If no leaking seals and no sign of burn down then.....hard to imagine it burnt down at idle too unless there was an air leak.

If he did a rebuild and installed the OEM size pistons, he might be past the wear limit on the cylinder, meaning pistons were too small, too much rock in it and the piston snapped a skirt. You will need to measure the good side piston and good side cylinder to determine what wear limit he was at.

 

[boots]

cat piston are pron to skirt failure ,,,,, i have heard about lots of 800 failling

 

[markoo]

Are those new pistons or just neww rings. Breaking skirts is a common problem but not under 3000 miles.

 

[moyiesledhead]

Need whole motor and do a pressure test on the case. If no leaking seals and no sign of burn down then.....hard to imagine it burnt down at idle too unless there was an air leak.

If he did a rebuild and installed the OEM size pistons, he might be past the wear limit on the cylinder, meaning pistons were too small, too much rock in it and the piston snapped a skirt. You will need to measure the good side piston and good side cylinder to determine what wear limit he was at.

Thanks Modman, good thought. I'll get him to take some measurements. As far as I know he replaced pistons, not just rings. Used OEM.

 

[boots]

mine went in 500 miles... and i have heard lots going in the first 1000 miles

Are those new pistons or just neww rings. Breaking skirts is a common problem but not under 3000 miles.

 

[smokindave]

I have one brand new crate motor left if he needs and I also have one top end kit left for M1000.... pm if you are interested

 

[0neoldfart]

Why was it being rebuilt the first time? Preventative maintenance, or due to a failure? Could be a crank seal, someone also mentioned oil pump couldn't be the problem - well, it could be if he premixed the first couple tanks of oil...I may add that the mag side generally runs hotter on the M1000. Possible the piston was nicked during installation, creating a stress point and potential hot spot, too...even a light smack will change the way it expands in the cylinder.

 

[moyiesledhead]

Compression was down so pistons were changed. New crank seals too. No real signs of heat. Not sure if he premixed the first tank or not. I'll have a better idea when I see it in person tomorrow. Thanks for all the input guys!

 

[moyiesledhead]

Well, the verdict is in. Banjo fitting off the oil pump for the PTO side oil line was broken. Found a hole punched through the bottom of the crankcase from piston pieces too. Second time I've seen that. Those little fittings are really fragile. Luckily we caught it on Catinthehat's M7 before we had the motor back in.

 

[moyiesledhead]

Here's the pics.

 

[gordhunt]

That sucks man

Sent from my Galaxy Nexus

 

[moyiesledhead]

Could be worse. We found the piece so the crankcase can be repaired.