June 22, 201115 yr Hi, I am carrying out the final assembly of my Tiger Cub and can't find which oil pipe is 'supply' and which oil pipe is 'return' on the bottom of the engine. I am fitting a top tube type oil tank and have put a feed from the return pipe for the rockers. Also what is the general view on fitting an external oil filter to Tiger Cubs? I have one but will get the bike running before I consider fitting it. I intend to change the oil regularly any way, so the only advantage I can see is that it would add another 1/4 litre of oil to the system. The disadvantage being that there are more possible leaking points! Any help would be appreciated, Bruce.
June 22, 201115 yr I don't know the bike, but on any bike I've messed with, the feed is physically above the return. It sure pays to be sure, though!! Again...not knowing the bike, but...an oil filter can only help. Only on the return...never the feed.
June 22, 201115 yr Author I don't know the bike, but on any bike I've messed with, the feed is physically above the return. It sure pays to be sure, though!! Again...not knowing the bike, but...an oil filter can only help. Only on the return...never the feed. Charlie, Thanks for your reply. Surely the return (to the oil tank) is above the supply which comes from the bottom of the oil tank. My Triumph Tiger Cub has 2 oil pipes coming from a small manifold beneath the crank Cases (dry sump engine). I guess if the worst comes to the worst, I can pour some oil into the crank case and turn the engine over to see which pipe the oil comes out. This will be the return! Even though I have fitted a Morgo (upgraded) oil pump, it still looks very small to start pumping oil around a Citroen 2 CV oil filter! I'm also not sure if the increased back pressure on the return line will affect the lubrication my tappets receive further along the oil return line.
June 22, 201115 yr The pipe on the outside of the manifold is the supply to the engine. The inner pipe is the return to tank. The top tube oil tanks usually do not have any kind of strainer or filter in them. Any debris is free to continually circulate through both sides of the pump,the mains and big end unhindered. Filtering the return means that any debris only passes through the scavenge side of the oil pump once (there should be a strainer on the end of the scavenge pipe up pipe in the sump to stop any really big bits) The filter does not offer much resistance to the flow (unless it is blocked and then the pressure by-pass opens in the filter).Any increase in pressure will be between the pump and the filter. The take off for the rockers is after the filter so will be uneffected. Most of the debris will be created straight after a rebuild as the rings bed in to the new bore.. if you are going to fit a filter.. fit it sooner rather than later. Edited June 22, 201115 yr by alan
June 22, 201115 yr Author Alan, Many thanks for your clear and concise answer. I plan on turning the engine over with the spark plug out until I can see oil flowing down the return pipe. Then I will start it and run the engine for about 15 mins on and off before changing the oil. I plan to put 15/40 mineral oil in the engine and gearbox (I got a gallon of it cheap in Wilkinsons!) and a drop of ATF mineral oil in the clutch to keep the primary chain wet. Should I be changing to semi synthetic once run in? I'll be off up the shed then! Bruce. The pipe on the outside of the manifold is the supply to the engine. The inner pipe is the return to tank. The top tube oil tanks usually do not have any kind of strainer or filter in them. Any debris is free to continually circulate through both sides of the pump,the mains and big end unhindered. Filtering the return means that any debris only passes through the scavenge side of the oil pump once (there should be a strainer on the end of the scavenge pipe up pipe in the sump to stop any really big bits) The filter does not offer much resistance to the flow (unless it is blocked and then the pressure by-pass opens in the filter).Any increase in pressure will be between the pump and the filter. The take off for the rockers is after the filter so will be uneffected. Most of the debris will be created straight after a rebuild as the rings bed in to the new bore.. if you are going to fit a filter.. fit it sooner rather than later.
June 23, 201115 yr Blimey i wish i knew the definitive answer to that.. There is a school of thought that says you should run in on cheap oil to help the rings bed in quicker.. but all modern cars use good quality oil which can be in for up to 20,000 miles.. they dont seem to come to any harm. My experience is that with synthetic oil, even with a worn out pump the engine did not come to any harm.. But with a new pump and a roller big end there would be ample pressure and flow using a mineral oil, A trials engine is not worked that hard unless you are doing road work on a long distance trial. Oil change frequency is probabley more critical especially with no filtration, so in my humble opinion buy cheap and change it often or if you can afford buy expensive and change it often.
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