Engine pics. I believe I'll have some down time...

[96sherm]

Spent last weekend in Valemount and Blue River. Last day, 6kms from the truck, my 2011 RMK Assault locked up, stalled, and skidded to a halt. Checked a few things over, the motor turned freely and even fired up, but the secondary clutch couldn't be spread to remove the belt. Back home now, I pulled the secondary off, turns out the main bushing was worn so badly it had twisted and locked up the secondary. I ordered parts to completely overhaul the primary also.

So while I'm having some things apart I decided to check compression which was 100/110, and figured while I'm in there, I'll freshen up the top end with the RKTek kit, and possibly a 13:1 head. Tonight I finished the teardown and here is what I find... Looks ugly to me I'm curious to what you [more] educated people have to say about this. Obviously the pistons are throwaways, but can the cylinder be re-lined/renikasil'd?

 

[06yamahaapex]

yes the cylinders can be re finished. How many miles on the sled?

 

[d mills]

Have used these guys. Excellent work.

http://www.google.ca/url?sa=t&rct=j&q=mongoose%20machining&source=web&cd=1&cad=rja&ved=0CC8QFjAA&url=http%3A%2F%2Fwww.mongoosemachine.com%2F&ei=wO0JUd6xNMfniAK_1YCwBw&usg=AFQjCNEAJ-q1OdbstSxOuaDTF9R_PShwKQ&bvm=bv.41642243,d.cGE

 

[glassman]

I have used mongoose for a few projects. No issues whatsoever.

 

[Shadam]

can it seriously be cleaned up ...
just saw a sister sled to mine with same scares ...
not pretty but not too ugly ... but stealer said block was toast.

rt1000 ...
I just want to learn no tthe hard way = expensive way ...

 

[CUSO]

Maybe it was a blessing in disguise that the clutch locked up..

Locater pin?

 

[96sherm]

yes the cylinders can be re finished. How many miles on the sled?

3900kms on the machine, no issues until now.

Those of you who have used the MongooseMachine, how much has it cost to have the cylinders resurfaced?

Cuso, I can't think of why the piston/cylinder has the damage it does. The locator pins are in their rightful locations, rim of the piston has some slight nicking, but nothing that would cause such damage to the piston/cylinder in my mind. Rings are intact but mimick the same scarring as the piston/cylinder has. I'm somewhat at a loss as to what could have caused it.

Thanks!!

 

[Jeffpro800]

Looks lean, wonder if your injector was partially plugged? Did your deto light come on often?
Just be glad it's just a piston kit and a renic/exchange monoblock, if it grenaded the piston you would probably be looking for an entire motor!

 

[96sherm]

Only time deto warning came on was at around 200kms when the sled was brand new. I was running premium fuel with the ethanol resistor when it happened (thought it would be a safe thing to do). I was told to run non-ethanol resistor with premium fuel and that if I had to run regular fuel in a pinch it wouldn't hurt anything. That's what I did and haven't had any issues.

There are some pretty nasty gashes on the top of the damaged piston...???

The whitish looking piston (suspect thats the one you say may be running lean) happens to be the cleaner/undamaged piston. While its all apart now, I'll change the brutally expensive fuel filter, oil filter, and pretty much have a new sled when I'm done

 

[Warhawk]

Not sure by the pics about your cylinder BUT before you condem it use muriatic acid with a very small brush. Apply the acid on the areas where the aluminium from the piston has transfered to the cylinder. Do this until it stops bubbling. Then use a sunnen hone to try and clean it up. This is all for not if you can catch a finger nail in a groove anywhere as that is atleast .010 deep which would be thru the nicasil or very close..
Looks like its the PTO side. Is the 4th pic from bottom showing the intake side of that piston?? It looks like it but i cant really tell.

 

[Jeffpro800]

It's possible your rings started to chip from wear and got snagged on the ports and it went downhill from there. Ya, it sucks but you will be happy with a fix kit if that's the route you choose to go, your engine will run much smoother.

 

[moyiesledhead]

Renic'd cylinders for your sled are $599 exchange from Recreation Supply in Saskatoon. Just send 'em yours back when you're done.

 

[Dazzler]

Not sure by the pics about your cylinder BUT before you condem it use muriatic acid with a very small brush. Apply the acid on the areas where the aluminium from the piston has transfered to the cylinder. Do this until it stops bubbling. Then use a sunnen hone to try and clean it up. This is all for not if you can catch a finger nail in a groove anywhere as that is atleast .010 deep which would be thru the nicasil or very close..
Looks like its the PTO side. Is the 4th pic from bottom showing the intake side of that piston?? It looks like it but i cant really tell.

It is a little confusing for sure... one piston looks like possible snowdust and the other a lean issue?? Muriatic acid and a q-tip will for sure clean up the aluminum deposits, and look closely for cracks!! But with that much damage I personally would exchange it for reconditioned.

 

[96sherm]

Thanks for all your replies. There are a few places that do 599$/core exchange, that is likely what I will be doing. Will go with the place that has the fastest turn around time. My father in law thought about the snow dust also because of the chipping and nicking on the darker (PTO) side piston. Service writer at the local dealer wonders about a crank seal worn and sucking air, or bottom case halves not sealed proper any more. It would suck in air and super-cool the pto side causing issues.

Also I'll be doing a RK Tek kit with 13:1 head. Time to be making a list of parts...lol...oil filter, fuel filter, gaskets, (already have clutch components coming). RK Tek stuff, etc...

 

[snowassault]

Hey Sears looks ugly in the pictures. Is there material missing around the ports or is it just build up from the piston? In any case i would either buy the used ones (dependent on condition) or do the core exchange. It is funny that you had this issue and it still ran as good as it did. If you want i can get some parts for you this weekend from toon town. Did you get your primary off? I got your message when i got home today. They can be a pain to get off, sometimes just have to work at it. Let me know how you make out.

 

[flying frenchman]

Looking at the piston it looks like the ring pin is gone. Was it still intact. If not, that that's the culprit.

 

[CUSO]

That issue was already covered, earlier in the thread.

Looking at the piston it looks like the ring pin is gone. Was it still intact. If not, that that's the culprit.

 

[flying frenchman]

My bad.

 

[96sherm]

Wonder if someone could enlighten me as to the PTO crank seal...does the cases have to be split or can this seal be replaced externally? I'm about to pull the whole engine out of there for two reasons, 1) I have had a leaky oil cap for some time and its created quite a mess everywhere, 2) easier to assemble the motor with new parts when its on the bench. I'm just wondering what else I should be doing while its out...

 

[96sherm]

Well, the motor is on the table. I got ambitious and got the engine compartment fairly well cleaned. Aside hanging the sled upside down and pressure washing it with a degreaser, it won't get much cleaner. I await parts now, fingers crossed that they show up by this weekend!!!