Got this old 400 up and running and trying to narrow down some oil coming from the exhaust. I did a compression test and all is good there. A cooling system test and no leaking there. Adjusted the oil pump and sealed up the pump so no water can get in it. The machine starts right up and runs strong but smokes a bit more than I'm used to. After running, I get oil dripping from the head pipe. Not gas or coolant, but dark colored oil. I pulled the plug and it is very clean and no evidence of soot or oil. It has the polaris blue oil in it but this oil is dark and obviously isn't going through the combustion chamber. I know it's not a blown head gasket since I ran it for a good half hour and no coolant blew out the overflow. It had good compression when I tested with the gauge and it darn near breaks your arm when you try and pull start it. This machine sat for quite a while so is it possible that there is build up in the crankcase and maybe this is all coming out now once I got it running. Any ideas what it could be or ways to check if I have anything in the lower case? I never had the motor apart so I don't know what was in there.

Thanks,
Mike

 

Probably oil in the crank case and may take a while to burn it out. Sitting up oil and gas can accumulate in the crank case. Gas will evaporate but oil will stay.Plus can also be accumulation of oil in the exhaust. I've had a bunch of smokers like this that I had to pull outside so I wouldn't choke everyone in the shop. Main thing is to make sure the oil pump is working ok. After you run a while pull the injector line at the intake manifold and see if the tube is oily.

 

Thanks OPT,

Is there a drain for the lower crankcase? I know where the counterbalance drain is, but not sure if the crankcase has one.

Thanks,
Mike

 

10 mm plug middle of the engine,just to the right of the counter balancer drain.

 

Well I pulled the counterbalancend plug and the crankcase plug and got somewhat milky oil out of both. I am not losing any coolant and I did a cooling test over again and still had no loss in pressure over a 12 hour period. I think I'm going to have to at least do the waterpump seals and may have to do the crank seals. I have done crank seals on the outer case but how hard is the inner crank seal to do on the counterbalance engines? I have put them in behind the flywheel but I believe there is another one in the counterbalance cavity behind the gear on the crankshaft if I'm not mistaken. This motor was split when they did the rebuild and I can see the fresh three bond on the crankcase halves. I really don't want to split it if I don't have to.

Thanks,
Mike

 

Just change the c/b oil and run it a while, keep a check on the level and also if oil becomes contaminated.Kinda hard for any thing in the counter balancer cavity to go through its seal and also the stator side crank seal also. Machines sitting up over time can get some moisture accumulation in the crank case along with oil.Just get out and run it and see how it does. Hurts machines more to sit up than running them.

 

Thanks OPT,

Was kinda worried thinking maybe it was sucking the oil into the crankcase from the counterbalance area. I remember seeing some older three wheelers that you could tell the crank seals were out on by how they smoked from sucking trans oil into the case from the bad seal. I will run it some and hopefully I can get it cleared out. I left the plugs on both the crankcase and counterbalance out over night so they should be both drained completely. I will top off the counterbalance and go from there. If I do have a bad seal, what is involved in changing that? I know the one in the stator case is relatively easy to pop out and put in, but the one on the other side of the gear on the crankshaft is the one I question. Can that gear just be pulled without pulling the counterbalance shaft so I can get to the seal to replace it? I know the seals are both the same on that side because when you get the crank seal kit it comes with two on the stator side.

Thanks,
Mike

 

Counter balancer seal replacement is the same as the crank seal. Just pop it out and replace it. Also just oil up the bushing that goes into this seal and twist it in so it doesn't damage or distort the seal lips. Counter balancer cavity seal is the same size as the crank seal. Item #36 (2)

 

Thanks OPT,

Now do I have to pull the counterbalance itself to remove the gear from the crank or can that be pulled separately so the seal can be replaced? And if u can, do I just need a regular puller to remove the gear? I hope I can run this thing enough and it will clear up but I'm planning for worst case scenario if it still pulls oil into the case.

Thanks,
Mike

 

Counter balance doesn't have to be removed,but make sure the marks on the c/b and crank gear line up after seal replacement. Gear may just pry off or a two jaw puller long enough can pull the gear.It's keyed so you can slowly line the gear up on the crank shaft and turn the c/b sprocket until the dots line up then push the crank sprocket all the way in.