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Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Cam Wear
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<blockquote data-quote="oexing" data-source="post: 93607" data-attributes="member: 1493"><p>Twin start oil pumps would not change the problem: You´d get double scavenge volume, but also double feed into the engine. So nothing changes. </p><p> The scavenge side of the pump is , say, one third bigger than the feed side. So in theory you could use that extra volume for lubrication from the scavenge line. But not any percentage more else the engine will fill up in time. </p><p> I´d have to dig into the oil system first, so question is, can there be a leak in the suction side of the pump somewhere in the engine case where air is drawn into the pump ? That would explain the poor scavenge action in our case - apart from a clapped out pump. </p><p> The piston type pump could provide quite some pressure, periodically, if there were no effectively open ends in the various lubricating places. So no luck to get a reading on a pressure gauge. But it should not be difficult at all to return oil from down in the engine up into the oil tank , pressure wise. I would not like to have a restriction from the scavenge hose into the oil tank. It does not make much sense I believe, as it should be sufficient to have the rocker feed lines simply filled with oil at close to zero pressure from the height differential rocker-oil tank. Just a gut feeling . . .</p><p></p><p> Vic</p></blockquote><p></p>
[QUOTE="oexing, post: 93607, member: 1493"] Twin start oil pumps would not change the problem: You´d get double scavenge volume, but also double feed into the engine. So nothing changes. The scavenge side of the pump is , say, one third bigger than the feed side. So in theory you could use that extra volume for lubrication from the scavenge line. But not any percentage more else the engine will fill up in time. I´d have to dig into the oil system first, so question is, can there be a leak in the suction side of the pump somewhere in the engine case where air is drawn into the pump ? That would explain the poor scavenge action in our case - apart from a clapped out pump. The piston type pump could provide quite some pressure, periodically, if there were no effectively open ends in the various lubricating places. So no luck to get a reading on a pressure gauge. But it should not be difficult at all to return oil from down in the engine up into the oil tank , pressure wise. I would not like to have a restriction from the scavenge hose into the oil tank. It does not make much sense I believe, as it should be sufficient to have the rocker feed lines simply filled with oil at close to zero pressure from the height differential rocker-oil tank. Just a gut feeling . . . Vic [/QUOTE]
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Tech. Advice: Series 'B' / 'C' 500cc/1000cc Bikes
Cam Wear
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