mixing synthetics motul 300v and yamalube 10W40

[Lurcher]

I have been using motul 300V in an older xr250r the reason being to keep oil temps down (this model cracks heads when thrashed) 300V is very expensive out here (New Zealand). I was going to switch to yamalube fully synthetic 10W40 which is cheaper but I have a little motul left I'd be mixing 1L of motul and 600 of yamalube or similar (possibly the other way round). How would this work out? Are there dangers??

 

[Chris142]

What about using 15w40? Is that available there?

 

[Lurcher]

Sure but if it's motul it will be expensive... I could switch to a semi synthetic but the yamalube is not a bad price, and as it's the recommended lube for likes of yammy dirt 4strokers like WR's it should be fine in the ole XR. Both the motul and yamalube I mention above are 10w40, I'm just unsure if they might make bad stuff or loose/gain viscosity when mixed.....

 

[Mr_Joe]

No problem in my experience. I do it to use up the last of any oil I have. If it was me I'd also find other alternatives than the expensive 'yama-lube'. If you want a synthetic how about one of the more common brands off the shelf, Mobile 1 & others like it?

 

[Mackelroy]

Can you use the motul as a top off oil over time?

While the mix probably wont be an issue, those two types of oils are Quite different. Id rather go with a full change, if going to do it.