Another Oil Question

[Dorianfes]

Ok...so say "somebody"  put 5w30 in my bike, even though I specifically said 10W40; would this really screw up my GS?  I did a search for 5w30 but only came up w/ a couple posts on preferences.  Does anyone know if an oil change is in order?  or is it ok to leave it?  about 11,000 on the tach. and plan on going on an 8 hr. ride on sunday.  I feel like the 5w30 wont be able to hold up on a long ride like that.  But then what the hell do I know?  (BTW got the bike started,obviously, but thanks to all that helped with the key issues).

Dorian

[galahs]

Should be ok. Might be alittle viscous for the wet clutch (may cause some slippage) but the GS is pretty tough!!! 

[hmmmnz]

if you are doing long rides its better to go for a oil that has a higher second number eg
10w50 the first number is just how quickly it gets moving around the engine and the second number is the lubrication value when it is moving and hot,
thats a bit laymen but you get the idea, i personally i have never used a 5wanything in my bike so i couldn't really tell you but id say stay stock or go 1 grade higher on the second number

[galahs]

I'll clarrify my answer too. If you don't want to drain it, it will be fine. Not the best, but ok. Probably good if the weather is still coolish but I wouldn't be filling it up with 5W-30 next time.

I actually use a 10W-60 synthetic. 

[scottpA_GS]

I put 10W40 in every thing... my 2 cars the bike and my truck!  Makes oil change day easier all around 

[sledge]

So long as the red light doesnt come on, there is enough oil in the engine, with enough pressure behind it to adequately lubricate and cool the internal parts. The numbers 5/30 relate to the the viscosity of the oil at certain minimum and maximum ambient temperatures. 5/30 is an all round less viscous (or thinner) oil then 10/40 and thats the only real difference. You need to look at it from 2 sides, when the engine is cold 5/30 is an advantage, it is thinner and will provide less drag on moving parts and be easier to pump around the engine making it easier to start. When warm it is also thinner in comaparison to 10/40, but this may be a disadvantage if you are running in a particularly hot climate or if the engine is wearing out and clearances have increased over time and with use. Oil becomes less viscous with heat and as result looses its ability to cling and hold pressure, its boiling point also drops meaning it looses its abilty to absorb heat and cool the engine. Unless you are doing a 14 hour run through the desert I wouldnt worry about it to much but I would get the correct grade in there as soon as is convenient especialy if you are in a warm part of the world. BTW It wont harm the clutch, being thinner it may even lighten it up slightly......Its all in the link.

http://physicsweb.org/articles/world/15/2/7

[galahs]

I have known people who have had their clutch slip when using 0W-40 oil, so just becarefull when using thinner oils.