wolle
New Member
Posts: 16
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Post by wolle on Jul 6, 2007 1:36:17 GMT -5
Hi
Oil was new when i bought the bike, few months ago.
Had a 1 km ride, and some idle adjustments.
The oil still seems almost new.
How to check lubrication pressure?
When the engine started, i tryed taking of the filler cab, there was some pressure in there, it that OK?
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Post by aero on Jul 6, 2007 10:37:32 GMT -5
Checking the oil pressure isn't as straight forward as that. Here's how Yamaha say to do it.  |
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wolle
New Member
Posts: 16
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Post by wolle on Jul 7, 2007 1:45:05 GMT -5
Thanks aero
ill try it today
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Post by wotavidone on Jul 9, 2007 19:30:52 GMT -5
The thing I find most ineteresting about this service bulletin is the insight into the Japanese motorcycle designer's thinking.
1) check the oil pressure right at the end of the supply chain.
2) very finicky about how hot and therefore runny, it has to be.
3) like all good practical engineers (a rather rare breed), why buy a pressure gauge when a length of tube will do to make a serviceable manometer.
But really, the most interesting thing is that oil is supplied to the exhaust rocker arm under pressure.
Makes me wonder why people spend money on external oil line kits.
Mick
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Post by colinjay on Jul 10, 2007 0:46:45 GMT -5
Mick,
The oil line kits are all "Hi Volume" kits, as the SR (TT/XT) engine has a low pressure lubrication system, about 7 - 10 psi, it is all about getting a sufficent volume of oil to the right places. The external oil lines supply more oil to the exhaust rocker than the internal oilway can.
Can you imagine the mess this test would make if you did it on an engine with 80 - 100 psi oil pressure, it would be raining engine oil!
CJ
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Post by miker on Jul 10, 2007 6:56:55 GMT -5
I wonder if "factory lapping" is one of the differences in the 80-81 oil pump, compared to the 78/79?
miker
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Post by canucksr on Jul 10, 2007 8:49:06 GMT -5
That's a interesting test for the oil pump. In the Yamaha service manual I have, they mention that the oil-pump was altered a lot between 1978 and 1979. In 78 there was 3 screws holding it together and in 79 the shape of the pump was changed and two extra screws were added to provide better sealing.
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Post by christoph on Jul 22, 2007 14:31:43 GMT -5
I'm curious how I would get or make an attachment for the rocker arm plug? Can you order it form a yamaha dealer?
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Post by aero on Jul 22, 2007 15:28:03 GMT -5
I'd make one from an old rocker cap, skim the dimple off and drill through it with a 5mm drill and thread it at 6mm.
You have to remember the engine is an all roller bearing engine, it doesn't need pressure to keep it lubriacted. How can can you pressurise an open ball race?
The only 'sliding' bearing (apart from the piston) is the rocker pins and the cam shaft lobes, which is where you are measuring the pressure using the Yamaha method.
They are talking about new machines, so yes they want to be sure they don't bugger up the exhaust chrome or seize the engine.
They wanted the dealers all over the world to actually do this work, rather then just say its been done, to ensure the reputation of the engine, so no expensive yamaha tools required!
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Post by christoph on Jul 25, 2007 18:13:30 GMT -5
yes I know all too well about the rocker arms! I just pulled apart my top end (after the valve gap kept getting loose) to find that the rocker arms hand been grinding itself off on the cam lobes! the intake rocker had worn right through the pas and was riding on the arm of the rocker arm! needless to say this time around I want to be sure that the rockerarms and lobes are getting the right ammount of oil.
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