"Plastic" zip/cable ties should not be used in potentially high heat situations. Metal ones exist but I find them hard to get tight. It's easier and more secure if you do the safety wire double wrap & twist off .
Double wrap is used when securing to a hose, to give 360 degree pressure similar to a hose clamp (without the weight & cost).
I also use "preloved" hose cut to length, whole (ring) or split (sleeve) to protect against abrasion/rubbing.- not so much for heat.
Many (on this Forum) swear by firesleeve. Not cheap, for ease of application/removal best to have compressed air handy,
I hope you are aware of the Rotax recommended 5 year replacement interval for ALL rubber components.