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oil
Dec 5, 2006 15:23:44 GMT -5
Post by wotavidone on Dec 5, 2006 15:23:44 GMT -5
I believe oils are rated as follows:
a 20 weight oil is relatively runny when cold, and too runny when hot.
a 40 weight oil is thickish when cold but reaches the right consistency when hot.
Therefore, a 20W-40 oil has the characteristic viscosity of a straight 20 weight oil when cold, but resists thinning when hot, so behaves like a 40 weight oil when hot. i.e. it has the right viscosity over a fairly wide temperature range.
Therefore a 20W-50 oil should to some extent be better, i.e. it is going to be the right viscosity/consistency/runnyness over a wider range of temperatures.
I would always be careful about going too low on the first number. i.e. you now see some 5W-40 type oils.
I would always worry about those being too thin for our SR engines when cold.
Mick
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oil
Dec 5, 2006 22:03:56 GMT -5
Post by colinjay on Dec 5, 2006 22:03:56 GMT -5
You are correct Mike, a 5W-40 would not be real good in an SR/XT/TT engine. These oils are designed for the latest types of car engine (especially the high performance ones) were the thin oil gives almost instant pressurisation of the lubrication system on engine start up. This is needed because of the plain bearing and tight tolerances used in these engines to prevent rapid wear on crank journels etc.
Put a 5W-40 into a 500 engine and you would end up with the engine wet-sumping even more than they normally do as it would leak down through the oil pump and check valve rather quickly. This is why good old pommie single like my 1949 Matchless G80 tend to use straight 40 or 50 weight oils.
Also as the SR/XT/TT engines are all ball/needle bearings the rapid oil pressurisation at start up isn't an issue.
CJ
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oil
May 15, 2007 9:21:23 GMT -5
Post by 1980thumper on May 15, 2007 9:21:23 GMT -5
so.....i should get non-synthetic 20W-50 for my 1980 sr500???
Damo
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oil
May 15, 2007 17:30:18 GMT -5
Post by colinjay on May 15, 2007 17:30:18 GMT -5
Damo,
Basically yes, that is what Yamaha listed in the manual and there is not much point in running expensive synthetic oil if the engine has not been moddified. The average 20W-50 oils made now are all better that what they were 25 years ago.
CJ
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oil
May 16, 2007 0:14:06 GMT -5
Post by canucksrf on May 16, 2007 0:14:06 GMT -5
I use 10W40 Valvoline in cooler weather and 20W50 when it's really hot in the middle of summer. A buddy tried synthethic oil and the clutch slipped until he switched back. Too slippery for a friction plate clutch I guess.
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oil
May 16, 2007 17:32:19 GMT -5
Post by colinjay on May 16, 2007 17:32:19 GMT -5
I suppose I should clarify my recommendation to stick with 20W-50 oil. As I have always lived in the warm-to-hot areas of Australia, I have had no reason to change the grade of engine oil to a thinner grade for winter. Basically, stick with what Yamaha recommended in the manual, if the manual says 10W-40 for cold conditions they would be right.
CJ
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uk500
Junior Member
Posts: 47
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oil
May 25, 2007 4:04:48 GMT -5
Post by uk500 on May 25, 2007 4:04:48 GMT -5
One of the ideas behind multigrade oil was to avoid running different oils in summer and winter, umpteen years ago people were running "straight grades" and needed to change for summer/winter, but unless you live in a climate with an extreme seasonal variation you don't need to , In the UK a hot summer can be 23/30 Degrees, but more importantly it can be minus 5 when your starting up at 6am in the winter, (bit colder than Oz :-) so maybe needed here? You can get the info regarding oils performance over a given temperature range from websites, (to put your mind at rest). Cheers,,,,,,,John
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oil
May 25, 2007 17:29:11 GMT -5
Post by chew652 on May 25, 2007 17:29:11 GMT -5
I don't know about OZ or the UK but here in the States the oil requirments of auto engines and bike engines started to diverge about 10-15 years ago. a high quality oil blended in the 70s or 80's would suffice in either. now days the auto manufacturers with the help of the Feds require things that do not work well with wet clutches and shear resistance needed for gearboxes. I pay the extra and buy motorcycle specific oils. I always had great luck with Spectro lubricants but any quality brand usually satisfies me. if you don't want to spend the bucks Wally World sells their brand of oil blended to the older specs. There was a discussion on the XS650 board recommending Rotella diesel oil as having similar characteristics to the older blends.
In the end though you get to put in whatever you want. Clean oil is good no matter what it cost. As for viscousity you won't go far wrong with the factory numbers. I use 20/50 here in North Carolina . Oil discussions are always a hoot,you should check out the Miata.net. Real warfare over there sometimes. Oil and grammar are the 2 hottest topics.
Sorry for rambling, it's a holiday weekend, Cheers all!
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oil
May 25, 2007 19:17:53 GMT -5
Post by davedunsboro on May 25, 2007 19:17:53 GMT -5
Yes me too I use Motul oil as it is over spec for any of my bikes manuals . I don't consider $30 for 5000ks too expensive either . So oils aint oils cheers Dave.
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uk500
Junior Member
Posts: 47
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oil
Jun 7, 2007 4:57:35 GMT -5
Post by uk500 on Jun 7, 2007 4:57:35 GMT -5
I know this threads been around a while but was wondering this, the recommendations are that you change your oil every x000 miles or three months, the three months bit I imagine is because over time the contaminants in the oil will be degrading it's quality and it'l need changing,,,,is that right? if thats not right what is, also if for example you'd just done an oil change at the end of the summer and you garaged the bike for a few months through the winter, would you really need to change the oil even if it had only been used for a couple of hundred miles? This might sound like a daft question but I never heard an explanation. Any thoughts anyone? Cheers,,,,,,,John
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oil
Jun 25, 2007 21:19:22 GMT -5
Post by fe2cruz on Jun 25, 2007 21:19:22 GMT -5
over time the contaminants in the oil will be degrading it's quality and it'l need changing,,,,is that right? if thats not right what is, also if for example you'd just done an oil change at the end of the summer and you garaged the bike for a few months through the winter, would you really need to change the oil even if it had only been used for a couple of hundred miles? This might sound like a daft question but I never heard an explanation. Any thoughts anyone? Cheers,,,,,,,John In the SR its more the heat. It makes the oil work harder than in a modern car or bike. So that is what kills the oils lifespan. |
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oil
Jun 25, 2007 21:34:23 GMT -5
Post by fe2cruz on Jun 25, 2007 21:34:23 GMT -5
Basically yes, that is what Yamaha listed in the manual and there is not much point in running expensive synthetic oil if the engine has not been moddified. CJ Mine has been modified does it require another oil an oil cooler, or just higher frequency of changes? home made loud seemingly opened exhaust 90mm piston Mikuni VM36 rubber oil line mod to hotter front valve-rocker K&N cone filter & rebreather (no airbox, but still has side covers) & its pulling the extra weight of a sidecar I'm not positive but I think the camshafts and valve springs were done too. How does the oil travel through the frame? Is it using a rubber tube or container within the frame, or is the frame itself containing the oil? In this state the bike is REALLY picky.The idle and air screw have to be in specific settings or it will not start. Its easy to kick through, and just needs a little creative blip of the throttle to stay alive on a hot start. This is something I have yet to master. If the settings are off, the bowl gets flooded or the plug gets wet and you have to wait to start it again. At least I think thats whats happening. As you can see the SR is still a new confusing experience for me. And I'm trying to learn, through lots of mistakes. Any advice will really help me through. |
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