I have a 72 iron head, 4 5/8 S&S stroker flyweels and .020 over S&S button pistons. Compresion chec has both juggs at about 150psi. I will ride the bike and some times when i stop and restart it will smoke real bad when i start it back up for a few min. Could my check valve in the oil pump be letting to much oil in the cases. and the pistons be picking it up with the bottom two rings and shoveing it into the combustion chamber any one know a quick fix

 

The ball leaking may be the cause of the smoking at start up, but I rather doubt it myself. This leaking usually happens when the bike has sat for a long time without being run.
When it is started up the excess oil sitting in the crankcase is sent to the scavenger section of the oil pump where it is pumped directly back to the tank.
But because the pump cannot move that much oil that quickly, the excess is blown out of the breather tube located below the generator.
So, to sum it all up.....If the bike dumps some oil out of the breather pipe when you start it, then perhaps the ball has let some oil leak by. However, if no oil dumps out but the engine just smokes for a short time, then I would suspect the valve guides are worn. Any excess oil that has accumulated in the case will be pumped back to the tank, and any amount over what the scavenger section can handle will be dumped on the ground. Non of this will result in excess exhaust smoke though. That is why I suspect the guides are worn.
Smoke comes from the combustion chambers, or oil spilled on your exhaust pipes. Nowhere else.

If you want to replace the ball in the oil pump, replace the spring along with it. Put the new ball into the pump and using a small blunt end punch give the new ball a light single tap using a hammer and the punch. This seats the ball in the pump body. Install the new spring..........pg

 

so you think valve guides may be worn. That may be true will check it out. could it possibly be the breather valve not moving enough oil through crank cases cause rember it is a stroker and the bottom two rings do go below the jusg skirt

 

Well it sounds like the guides may be a bit worn. When you shut off a hot engine the oil will pool around the base of the guide. If the guides are worn, this oil pool (small as it may be) runs down the valve stems and drops onto the piston if the valve is open or collects on the vavle head if it is closed. In either case when the engine is fired off the oil burns up causing the smoke.
Once the oil burns up the smoke will end for the most part. Thats the theory anyway.
Yes I know you have a stroked engine. I do not know how the stroke was achieved (relocated crank pin/different flywheels and/or different pistons) but I am sure the bottom 2 rings do not go below the bottom of the cylinders. Were that to happen, both rings would be broken instantly. Likewise, the purpose of the rings (compression) would be negated as soon as the rings 'fell out' of the bore. I trust I just mis-understood your terminolgy on that one.
As for the breather valve not moving enough oil.....all of the oil gets pumped throughout the engine. The last stop for this oil is the bottom of the oil pump (scavenger section) where it is pumped back to the oil tank at the same rate of flow as is coming into the scavenger section from it's trip throughout the engines insides a moment before. If there is extra oil it is puked out the tube. The fact that the engine has a longer than normal stroke has nothing to do with the breather timing or the amount of oil (flow rate) sent back to the tank.
Maybe someone else has another opinion on this, and if so please chime in here. I do not want to cause you to have to pull the heads without a reason, but this is what I think is the problem.
Question: Are the ends of the pipes oily? One pipe, or both?.......pg

 

Thanks for all the help, Ok now here is the real puzzling thing. When you go to start it up after it has been warm some times the motoris supper hard to turn over you can stand on the kicker and it will verly movewhen it does start then that is when it really smokes. I guess that is what makes me wonder if there is to muchoil in the cases causeing presure other times it starts up no smoke it does not do it all the time I do have a eletric start on the bike also some times you have to use both kicker and elect at the same tim to get it to turn over. just reciently installed compresion releses to help you leg and starter

 

{When you go to start it up after it has been warm some times the motoris supper hard to turn over you can stand on the kicker and it will verly movewhen it does start then that is when it really smokes. I guess that is what makes me wonder if there is to muchoil in the cases causeing presure other times it starts up no smoke it does not do it all the time}
You have 150 psi compression on both cylinders (that is good) and a stroked engine. I believe that is the reason you have trouble kicking it through.
The compression being at 150 makes me even more certain that the piston rings are holding well. That leaves the guides as the reason for the smoke.

When the pistons come down, this would create a pressure in the lower end (as you know) if not for that breather tube below the generator. The pressure from the pistons coming down goes out of this tube.
The air in the crankcase contains a mist of oil as well. This oil would come out with the air except there is an oil slinger fastened to the end of the generator drive. This separates the oil and the air. The air goes out and the oil remains inside. When the base has really loaded up (from the ball leaking/bike sitting a long time) the oil slinger cannot separate such a large amount of oil and so the oil gets puked out the tube, along with the air.
Under normal conditions the only oil to want to be shot out the breather tube is in mist form and the slinger separates it out and only the air escapes.
Any kind of pressure in the lower end caused by the pistons coming down will easily be vented out the tube. That is why it is there. The piston rings seal the cylinders so that no pressure at the top of the piston escapes to the lower end and....vise versa, no pressure in the lower end (there is none anyway because of the vent tube) cannot be forced back up into the cylinder to be burned as oil resulting in smoke.
I really think the problem is your valve guides. It does not always smoke? That just says the guides do not always leak oil down into the cylinders.......pg

 

my sporty