Help Please!!!!!

[yamaha1470]

Hey i just got a 400EX and the dealer told me that they will put in 10w40 half synthetic half regular oil. Is that ok or should i tell them to put in full synthetic 15w50? I live on long island so you can get an idea of the temperature. What should i do. will 10w40 hurt it?

no 10w40 is good for it. IT is what i run in my race quad and what several motor builders have sugested to me. i run Maxima "maximum" 10w40 as sugested by duncan racing after the built my buddies 440

[yamaha1470]

I am going to go with a 15w-50 synthetic oil. Who makes this? I was on the mobil one site and it said they have 20w-50 V Twin oil or 10w-40. Who makes 15w-50?

[Ex'r Marlin]

Mobil 1 has 15W 50 that some of us ExRiders.com guys use. I too now run the Mobil 1 in my 400ex. (I used 10W 30, but I will switch to the 15W 50). It happens to be an automotive grade that you maybe able to get at the local auto store.

Note: I have heard that it is not a good idea to run sythetic oil on a new engine or an engine that has just been rebuilt.

ex'r marlin i use the same stuff

[300exryder]

i too use mobil 1 synhetic 15/50. What is the difference between summer and winter oils -- i thought it would be thinner for the winter and thicker for the summer but when i changed the oil it was the opposite -- the winter was 10/40 (not synthetic) and it was thicker than the summer. Am i totally confused and wrong or what...someone fill me in.

[SGA]

Yep, it can be confusing with so many opinions. Conventional 40 weight oil is good for the summer (will not become too thin) but becomes too thick in the winter to lube the bearings upon start-up. So the oil companys made multi grade oils, 10-40, etc. Good lubrication on start-up, but will not thin down once warm. However, an air cooled motorcycle type engine runs alot hotter than most engines and can break down oil quickly (breaks down the molecular bonds in the oil) , even 50 weight. Along comes science with synthetic oil. Full synthetic can take far more abuse and not break down. Thats why many people run it. However, it is reported that in a NEW engine full synthetic oil will not let the piston rings seat properly to the cylinder walls. Many people break a new engine in with conventional motor oil, then switch to the better lubrication properties of full synthetic oil.

Heres a couple of links about motorcycle oil:http://www.yft.org/tex_vfr/tech/oil.htm
http://www.nightrider.com/biketech/oiltest1.htm

[Scott]

Can't say it much better than sgaexer did!:cool:

so tommorow when i get my 400ex shgould i break it in with the oil that the dealer puts in it or with other oil????

[Scott]

It will be fine to break it in with the oil that comes in the quad. Only point people were trying to get across to you is to break it in with normal oil before switching to a synthetic.

[lil400exman]

now that i think about it i use rotella t 15w 30 multigrade its a good oil and all semi truckers use it and i know guys with that oil that just change fliter i dont though and they just put new oil in to change the differece lost! its a really good oil it doesnt make a clutch slip dont fall apart at high temps its cheap i reccomend it 110%!