canning in august

Can't be specific on temps, others will no doubt fill you in.
Just thinking of 1 vehicle brings to mind the following. The Canning would have to be the longest and most isolated track that I know of in Oz. If your vehicle breaks an axle, diff, or other major component then how are you going to get anyone out ? You have another 4 people depending upon that vehicle. It's unlikely that the bikes will be able to carry enough fuel and water to be of much value on their own.
Chances are that you'll have a great trip with no dramas. But it's prudent to ask what are the risks, and how would another vehicle make the possible risks lower ? I guess you could look at it from the perspective of one of the bikers. Would you rather travel with one vehicle or two ?
Yes, I'm an old worry wart I guess, but you know about Murphy no doubt :))

Sounds like a good trip. August September won't be hot, in fact nights can be bloody freezing...literally. Regarding gear, tyres vehicles etc try ringing Kev at K & B Auto electrical (08 91852070)in Karratha. He and his mates have done some big 4WD & bike trips in the Pilbara.

Hi , we travel the c,s,r,many times a year , September can be very hot out there and water can be hard to find , we run motorbike tour on the c,s,r but always run to 4x4s to carry alot of fuel, bikes use a lot (heavy sand)and cart a lot of water /food
two 4wds just in case (duty of care) also to tow one over the sand hills from time to time BUT I BELEIVE YOUR BIGEST PROBLEM IS OBTAINING A PERMIT TO TRAVEL THE C,S,R ON BIKES . if you need more ifo give me a call 0428930319