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Discussion Starter · #1 ·
Ok, I've got 417 on my rebuilt motor (all new gaskets and seals, except crank.....all new pistons, rings, etc). Sled is running awesome, plug color is actually a little rich so I just lowered my needles one notch.

My question is in regards to some oily gas residue that I'm seeing up around the front pto side of the engine, and on the drive gear of the electric start motor. I know its not the pto crank seal, because I took the clutch off and checked it. Its dry all around and isn't showing any signs of leaking.

Even if the crank seal or the base gasket were leaking, don't they suck air in? Would it even be possible for them to spit that black oily gas stuff out?

I know that exhaust gaskets will leak and do this. But I can't be exactly sure where its coming from. Anyone have any ideas?
 

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Discussion Starter · #3 ·
No Riley, thats the thing, I'm not sure exactly where its coming from. I know it looks like an exhaust leak, but its hard to tell from the oil spatter pattern. I wipe it up, ride for a while, then check it, but I'm just not sure. Would a base gasket even leak out this type of black oil/gas mess? Or would this ONLY come from a leaky exhaust gasket?

I'm leaving this coming Sat for a week long snowmobile trip in northern Maine, so I'm a little paranoid about it.
 

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Look where the exaust pipe meets the pipe that attaches the motor. The part where the springs hold those two parts of the exaust together. Look on the underisde of where these two meet. On my 97 xc 440 I had this problem. A black oily like fluid was coming out of here and getting on the block. I thought it was bad exaust manifold gaskets so I replaced them. This didn't solve the problem.
It was coming out where these two pieces meet.
What you can do is put more washer or spacers where the pipe sits on the rubber ball or out fiber glass insulation around the part that I described as leaking. Hope that I helped you
 

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also, you can mount little pieces of aluminum sheeting, to block the oil from spraying on it from suspected areas, like the pipe/manifold connection.

My 440xcr has alot of exaust oil that spits back from that connection onto the motor.

-Dean
 

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Use high heat silicone (red) to seal the joins between manifold and pipes. It is clean, works, and it's what the manufacturers use.
 

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Discussion Starter · #7 ·
Thanks for the info and ideas to all that replied!
 
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