Oil Line valves

[Vintageman]

As asked before me - is it pump, lines, or check valve doing this flow differencing.

I am guesing pump from what I have seen of lines. If so line restriction can affect difference within a group: be it crank or piston. How much depends how much diff maybe +/- 10% is probably OK (still guesing)

What about 500/350/250 style pump/lines? I think line spilts into one crank one piston if I recall.

Maybe twins are different than triples?

[yeadon_m]

The GT triples at least have pumps which have 6 outlets. Each pumps individually so it matters not what the cracking pressures are on the check valves, provided they are easily overcome by the pump. Which they will be. Its a dam fine pump and oil won't compress!

So the oil pump won't allow for differential flow down the lines except as designed by the pump internals and the position of the lever. I think, anyway. Not 100% sure of this, because though there are 6 holes under the pump, there are really two sub-pumps, each with one piston (one for crank, one for upper cylinder) and perhaps I'm wrong - if you blocked one line, would the other two on the same circuit just pump more? someone may know. I really can't imagine the difference between cracking pressures could matter - else over time, when one jams open as they do, the other two lines on that circuit would be starved and this does not, to my knowledge, happen.

Brain hurts!

Mike

[gt-keith]

Before your brain finally expires Mike, have a look at this and please explain plain Anglo/American English. Or have you just done that.

http://www.pinkpossum.com/GT750/Oilpump.htm" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

[tz375]

To be fair to all those with exploding heads, some of us are talking about GT750s and some of us are talking about twins.

Triples have 6 outlets and two different plungers, so 3 high flow and 3 low flow.

As far as I know, twins use a twin outlet pump that has a flow splitter and that means that they either have the same flow through each leg or there's a flow restrictor of some sort in the line.

[pearljam724]

Is that the price for 4 valves ? Why can't they be sold in a set of 6 ? Why can't they work on the 750 also ?

[GT750Battleship]

Hi,if you look on UK Ebay the valves are for sale for the GT750 5 valves £55 pound,
Why 5 ? one of the lines behind the starter motor has a different end attached to the line,I don't know the real reason for this,maybe it's got to do with clearance for the starter motor ?
I'm sure some one will enlighten us !

Regards,
Roger

[jabcb]

Is that the price for 4 valves ? Why can't they be sold in a set of 6 ? Why can't they work on the 750 also ?

They having listings for 4, 5 & 6 valves.

[Coyote]

That's why I said in my first post. The springs -- seems most critical I realize the 2 different flow rates (crank / cylinders) is controlled by the pump design. That's a gimme.
But think about this. If ALL lines were capped off would the pump explode? No. It would just be in a state of constantly flushing itself (internal bypassing). This leads me to think if the springs are too strong, the valve will never open. If the spring is weak, why even have the valves?
If 5 valves are blocked, the one that is open wouldn't flow any more that normal. I some lines are partially blocked, they will not flow as much oil as the ones that are open. So my thoughts are if the valve spring is too stout, that valve will never open. Same as being capped off.
It's all too complicated. Buy a Yamaha. Bone simple. 2 lines to the carb intakes creating pre-mix and that's that. I could be wrong, but I don't think they incorporate ANY check valves The are not needed. I say 2 lines because I am thinking twin. To my knowledge, Yamaha never made a 2 stroke triple. They did make a 750 triple, but it was a 4 stroke.. blah blah blah -----

[rbond]

I have a GT500. My question is, could I replace all the oil lines from the pump to engine with, for example- tygon type fuel line, with four of those check valves and it would work fine? If I remember correctly, two lines exit pump to a 'y' block each. One leg goes to intake, one to case. So that means the same pressure is supplied to all lines?

[jabcb]

I have a GT500. My question is, could I replace all the oil lines from the pump to engine with, for example- tygon type fuel line, with four of those check valves and it would work fine? If I remember correctly, two lines exit pump to a 'y' block each. One leg goes to intake, one to case. So that means the same pressure is supplied to all lines?

A forum member tried that but it was before these new valves were available.
I took a quick look but didn't find the topic.

I think he used tygon that had the same ID as the original lines.

Might be worth revisiting now that these new valves are available.