Getting rid of the roll over valve

[ROCKERDAN]

Guys,
I urge you to take a step back and think about why the factory uses a 5/8" vent line in the first place! It's because there is a LARGE volume of air flow at higher RPM! What you feel flowing out of the oil tank at idle is only a fraction of what the flow is at 9000 RPM!
If the engineers had felt that a 3/8" vent was sufficient, then they would have built the sled that way in the first place!!!!! Why? Because it would been easier to package in to the sled AND it would be cheaper for them to do so!

Several years ago a guy came up with the idea of using a $10 PCV valve as roll over valve. Well another member thought that it sounded like a good idea and tried it on his Phazer. The result was he blew up his engine due to a bottom end failure and the OP ended up re-posting a warning not to try it. I can see where this thread might be heading in the same direction.
Someone could be reading this thread and thinking that "well the OP used 5/8" hose and I don't have any 5/8", but I have some 3/8" so that should work". Well it might or it might not. If doesn't work, you run the risk of pitching a rod through the side of the block.

The bottom line is that's it's your sled and do to it what you want. But please understand the oil tank vent is not the same as a valve cover or gas tank vent. The flow requirements are far greater and vary with RPM, engine load and oil pump/scavenge pump flow rates. Remember the oiling system is the life blood of your engine and the breather system is engineered to use 5/8" tubing/hose for a reason.

Bill

Good post and a good point to bring up.

I may be way off here, but I believe the larger 5/8" hose in conjunction with the stock valve in there is to help open that valve, and we all know they were freezing which caused major probs.

With the valve gone entirely, and the new setup i run having an entirely OPEN END, it will never build any pressure, and push air out at will....no matter what the RPM behind the motor. I dont think i'd go smaller then 1/2'' ID though.

Dan

 

[theewarrior]

I think the larger hose is just to keep pressure low why going in the intake so the engine has lots of time to burn it ,when opening it up completely it will never build that a 3/8 hose won't take care of ,,, just my thoughts

 

[theewarrior]

I actually revved the engine up and still could just feel a faint breeze out the 3/8 size

 

[theewarrior]

Take a 3/8 air hose on your compressor system and cut the hose with 150 pound pressure in it see how quick it will empty

 

[Pstn head]

Guys,
I urge you to take a step back and think about why the factory uses a 5/8" vent line in the first place! It's because there is a LARGE volume of air flow at higher RPM! What you feel flowing out of the oil tank at idle is only a fraction of what the flow is at 9000 RPM!
If the engineers had felt that a 3/8" vent was sufficient, then they would have built the sled that way in the first place!!!!! Why? Because it would been easier to package in to the sled AND it would be cheaper for them to do so!

Several years ago a guy came up with the idea of using a $10 PCV valve as roll over valve. Well another member thought that it sounded like a good idea and tried it on his Phazer. The result was he blew up his engine due to a bottom end failure and the OP ended up re-posting a warning not to try it. I can see where this thread might be heading in the same direction.
Someone could be reading this thread and thinking that "well the OP used 5/8" hose and I don't have any 5/8", but I have some 3/8" so that should work". Well it might or it might not. If doesn't work, you run the risk of pitching a rod through the side of the block.

The bottom line is that's it's your sled and do to it what you want. But please understand the oil tank vent is not the same as a valve cover or gas tank vent. The flow requirements are far greater and vary with RPM, engine load and oil pump/scavenge pump flow rates. Remember the oiling system is the life blood of your engine and the breather system is engineered to use 5/8" tubing/hose for a reason.

Bill

Imo I'm pretty sure Mtnviper knows a thing or two about how engines should and should not breath. Never met the man himself but has designed a product for years that keeps the engine oil in our motors in the case of a roll over. I hope I never need a rollover valve but if I do I'll more than likely go his route. Having said that I don't mean to diss anyone here becouse there a ton of intellect here on this forum but it's just I assume Mtnviper has done possibly bench testing and field testing before releasing a product.

 

[fatchance]

It's vented to prevent pressure build. Blow through the roll over valve when you have it out of the sled. I didn't gauge it, but I'm guessing it takes about 3 to 5 lbs to open the valve. Then put your finger over the "breather tube". It builds pressure pretty quick at an idle, but Probly not quite enough to open the valve. I believe this is when the roll over valve has time to freeze up....after you've gone for a rip and the moisture rises up through the Roll over and builds at the orifice once stopped or slowed then with enough time closed it's frozen. Punch it again and there goes the seal.

 

[XP123]

Is there any reason the oil tank would need a little back pressure? I was wondering if there might be a reason and I'm hoping we all didn't jump on removing the valve prematurely.

 

[fatchance]

Yes. Emissions. EPA. There would be no need to have and extra 3 lbs of pressure within the system. The system is designed to burn off blow by

 

[Mtnviper]

Excessive tank back pressure is far worse then to little breather pressure and it is excessive tank vent back pressure that can cause oil leaks.
When I measured the oil tank vent back pressure on a new (0 miles on the sled) King Cat it was averaging around 1 to 1.5 psi. While a Viper and Nytro (which do not use a normally closed ROV) test out at near 0 psi. I would think as long as your system is able to flow enough air so that it doesn't exceed the factory pressure during a long WOT pull you should be OK.

It is worth mentioning that with an open hose vent system, if you do roll the sled and the oil pump looses prime it may not self prime when you restart the sled. The stock ROV accomplishes the re-prime process by maintaining the 1 to 1.5 psi of vent back pressure, while we accomplish the re-prime process by using the shut off valve and regulated voltage. If you do loose prime with an open hose vent, you can re-prime it manually by temporarily capping the breather hose. When doing the manual method you have to work quickly though and be careful not to leave the breather capped for to long otherwise excessive oil tank back pressure will build up. The manual method works in a pinch (no pun intended), but I sure wouldn't want to have to do it several times a day when mountain riding!

 

[Dalton]

Just so I have a clear understanding of this, the stock roll over valve is worthless because it can freeze shut, thus applying more pressure than supposed to blowing out the oil tank seals?

Is this something that is inevitable to happen? I read in here that someone said Yamaha is supposed to do a recall or heard of it possibly happening?

 

[XP123]

Excessive tank back pressure is far worse then to little breather pressure and it is excessive tank vent back pressure that can cause oil leaks.
When I measured the oil tank vent back pressure on a new (0 miles on the sled) King Cat it was averaging around 1 to 1.5 psi. While a Viper and Nytro (which do not use a normally closed ROV) test out at near 0 psi. I would think as long as your system is able to flow enough air so that it doesn't exceed the factory pressure during a long WOT pull you should be OK.

It is worth mentioning that with an open hose vent system, if you do roll the sled and the oil pump looses prime it may not self prime when you restart the sled. The stock ROV accomplishes the re-prime process by maintaining the 1 to 1.5 psi of vent back pressure, while we accomplish the re-prime process by using the shut off valve and regulated voltage. If you do loose prime with an open hose vent, you can re-prime it manually by temporarily capping the breather hose. When doing the manual method you have to work quickly though and be careful not to leave the breather capped for to long otherwise excessive oil tank back pressure will build up. The manual method works in a pinch (no pun intended), but I sure wouldn't want to have to do it several times a day when mountain riding!

What about when we change our oil and filter? Will we need to close off the open hose for a few min so the system can prime itself?

 

[KnappAttack]

I see no where mentioned in the manual where you need to "prime" the oil pump on the SideWinder. Nothing in the service manual either. Even the oil filter goes on dry, which I don't like doing, but whats one to do when it goes on sideways.

I see no reason mentioned anywhere to "prime" the oil pump like we had to do on the old Suzuki twin 1100 turbo. If Yamaha does not tell you it needs done, why do we worry about it at all?
I changed my oil AFTER doing this mod and it had oil pressure right away even with a dry filter. It didn't need primed to get oil pressure.

Ski-Doos don't need this high buck electronic ROV system with their simple and actual gravity shut off roll over valve. Nor do they need pressure in the tank, it is equipped with the same dry sump system on the Doo's and they don't need priming either.

 

[fatchance]

Don't over think this, it's not rocket science. I've spent my entire life maintaining big power diesels and building big power high displacement gas engines. Who are we kidding here. It's dry sump. The engine starts and builds pressure by the pump pulling oil from the pan.there is no magic here, no smoke and mirrors. Yes if the sled rolls and the pump can't pull oil it will run dry and not push oil through the motor. Simple as keeping the skis down. You roll it you run the risk of running the system dry which compromises the motor, which by the way will happen if the seal blows out of the tank. Pick your poison.

 

[Mtnviper]

What about when we change our oil and filter? Will we need to close off the open hose for a few min so the system can prime itself?

No there is no need to prime the pump when changing the oil and filter. This is because the oil pump still has oil in it and it will self prime.

Typically the only time you may need to re-prime an oil pump, is if it has drawn in air and lost oil pressure. For example if you lay the sled over and the engine is still running. When this happens, the inlet port in the oil tank may be exposed to air and consequently that air could get drawn in to the pump causing it to loose prime.

On the Sidewinder, the stock normally closed ROV allows it to be somewhat self priming because the vent back pressure forces oil back to the oil pump inlet once the engine is started.
The main draw back (and topic of this thread) is that the stock ROV may be susceptible to freezing closed.

I guess the point that I'm trying to make is that when you make a modification, it can change the other factors as well. In this case when you convert to an open vent system on a Sidewinder you are basically converting it to a Viper breather system only without the Viper's air/oil separator tank.
Will it work? Sure it will, but with that in mind Viper/7000's can and do loose prime fairly easily if you roll them a certain way. I know, it happened five times to me the first day I rode my 7000!
If you never roll your sled then it's no big deal. However if you like to play off trail or ride the mountains, then the chance of loosing prime is something to keep in mind and be prepared for.

 

[ROCKERDAN]

I actually revved the engine up and still could just feel a faint breeze out the 3/8 size

I did same.....barely any more then at idle.