Oil viscosity for summer?

My wife's owner's manual states 10W40 is required, which I've been using, but I was wondering if anyone here moves to a 20W50 during the hot summer months? I always have used a 20W50 in the cruisers during the summer, and the manual for my zx14 recommends the same.

Any thoughts?

 

Run the same year round. BC does not get that hot. Cruisers are (mostly) air-cooled, so they get hotter, thus requiring an oil with a higher viscosity.

Most important thing is to use a quality motorcycle specific oil and filter and change it on a regular basis.

 

Thanks.
I live in the Okanagan Valley, our daytime temps in July and August range from 100'F up to 115'F or so.
And we're heading out on a 2 week trip thru Montana in July and i want to make sure the bike is set up right.

Thanks again, I appreciate the info.

 

i would go with straight 5 wieght its the best.

 

I think you are misunderstanding something. Straight 5 weight oil would be a HORRIBLE choice.

Now, if you meant 5w-30 thats a little different.