Forum

[Adrian]

Our hosts' PRV is for the scavenge side, that won't help the feed side trying to pump cold straight 50 oil into a plain big end bearing! A.

[Norm]

3 things working against the poor spindle here apart from the scavenge pump clearance issue, heavy oil,high cap pumps and a floating bush, not good

[simon]

So the saga goes on. Put the bike back together with the new turning hi cap pumps and take it for a test run. Come back with half the oil tank over the back wheel. Gasket blocking the scavenge side methinks but not so. I reassemble again and something tells me to check the feed to the head. Not a dickie bird. No oil going to the rockers and even when I squirt oil down the hole it doesn't pump out. Deeply confused now i replace the old feed pump and get instant pressure and a flow of oil. So I've replaced the scavenge side as well. Seems the holes in the hi cap pump are slightly further apart and aren't aligning sufficiently with the oil ways. Bit over the whole jag now. I've got all the old kit back on the bike but it's still spewing oil over the back wheel. Might have a head gasket leak pressurising the crankcase. Some days you should stay in bed.

[PeteF]

Straight 50 in winter? I know it's been warm but...
Multigrades are the way to go.

[another Allan]

Sorry to hear the problems you're having, Simon. Are you sure that the oil feed pipe isn't blocked? I know you said that there was no sign of big-end metal anywhere, but if there is no oil supply 'upstairs' even when you are using your original pump, it seems that a blocked oil feed pipe could be to blame.

[Norm]

Simon I don't want to tell you how to suck eggs but do you have the pumps the right way around as in scavenge pump at the front. What confuses me is you say you changed the feed pump, not sure why you would do that if it is pumping oil out the breather. Misaligned holes in the high cap pumps is not uncommon, Tim has banged on about it for years. If it is still wet sumping, pull the rocker blocks and check them for white metal, good reason why the scavenge pump can't clear the sump

[simon]

No they only go the one way round Norm as the bodies of the pumps are different widths and the scavenge is to thick to fit in the feed side. That's said the reason I replaced the scavenge pump is that I decided that as the feed wasn't pumping oil to the head that 1. I couldn't have faith in the scavenge either and 2 that might as well be matched. The oil coming out of the breather I think is due to excessive blow by probably from a reused home made 1mm solid copper head gasket Either that or something else that's for certain or not.

[simon]

No the feed pipe is clear Allan. The oil pumps fine with the old pump.

[Norm]

Simon, I'm totally confused, where is the scavenge pump pumping oil to? Head gasket will not cause blowby because it is above the piston

[Adrian]

So if the scavenge pump is fine and the rocker pipe itself is clear, the oil should then flow through to lubricate the rockers, then down from the head, into the pushrod tunnels in the cylinder and onto the cam follower stems and guides in the tappet adjuster chamber before passing through the holes into the top of the chamber behind the timing cover to fill the camshafts' and timing gears' oil bath. The overflow from here drops back into the oil tank. The oil in the timing gear space is being properly circulated as you have a full set of timing gears driving an SR1 magneto (if I remember right). Hmm.



Are the rocker block oilways theselves clear? Norm has alreadt suggest stripping the rockers out to check. Is the oil tank cap vent clear? Is the oil tank cap itself not screwed down too tight onto the second notch (the transport rather than the run position)? If the return oil can't get back into the oil tank easily there'll be more wet sumping as it seeps past the timing side mainshaft (I'm not sure if many of the 350 ever had the crankcase seal the Indian 500's used).



Forgive me if this is all stuff you have already looked at, I share Norm's confusion and am just trying to get **MY** head around what's happening.



Regards,



A.