I’d try TS flight lines, if you not already.

aircraftspecialty.com

Hi Robert,

Subject to your local regulations for your aircraft maintenance; You can reduce the 5 year "rubber" replacement cost significantly by using automotive hoses.

I use Gates products (there are other reputable hose suppliers). Gates automotive fuel & coolant hoses & Gates low pressure hydraulic oil return hose.

In every case the hose meet or exceeds the Rotax supplied hose specifications.😈

As Sean mentioned:

Local buys;  Gates Barricade hose for fuel 5/16" and 1/4". Use the carburation / vapor recovery hose from them. It's rated to 50 psi (carbed engine only) and is better suited to push over barbed fittings vs the fuel injection hose rated at 100 psi.

Just a note** The fuel injection hose has no give and you could strip out the inner lining forcing it over a barbed fitting.

Then get some Gates green stripe 1" (25mm) coolant hose.

If your carbs have never been overhauled then I would get those done too.

Rotax parts from a service center;

Get 3 meters of 17mm coolant hose, one pre-formed 90 degree 17mm hose two rubber carb sockets and "O" rings, Carb top rubber diaphragm's, the two rubber hoses sleeves on the carb balance tube,  Plus some Parker blue oil hose it's 12mm. California Power Systems sold this for a couple of decades and I've been using it for 25 years and it works well. More than enough temp and pressure rating. Buy it online. 

Parker High Temperature Multipurpose Hose 300-400 PSI – Blue 836-8 RL Hose

If you're changing the rubber engine mounts then you can get those online too.

I use Oetiker one eared clamps for all fuel 13.3 mm for 1/4" and either 14.5mm or 15.7mm for 5/16" hose depending on what the 5/16" is being installed on,  use the spring clamps on the 17mm coolant hose, you can use either Oetiker clamps or 19mm fuel injection clamps on the oil hose and for the 1" coolant hose I use Wurth Zebra clamps. These are by far better than the old style serrated worm drive clamps.

In 25 years I've never had a hose or clamp issue.

Additional note on 25mm (1") coolant hose.

Many applications require a significant bend in the hose. Using straight hose in these applications can put significant side load on the radiator spigots and has the potential to collapse the hose at the bend.

To overcome the above potential I cut to length Gates ;

Moulded 90 degree bend, in diffrent "Arm"  length options

• PN 03-0010 ID 25.4mm, Arm 1 125mm, Arm 2 125mm  
• PN 03-0011 ID 25.4mm, Arm 1 300mm,  Arm 2 300mm

Multi Fit Coolant Hose with two bends, a 135 & 90 degree

• PN01-007 ID 25mm Length 550 

Unfortunatly I must use one connector. You can choose from;

• Straight PN28606 
• Elbow PN28626 
• Tee PN28638 

My oil hose is Gates hydraulic 8GHT

I use Gates Barricade fuel injection hose, over automotive style spigots (without sharp multi barb grips). Not for its higher pressure rating but for its slightly higher temperature and vapour transmission rating.

The old style multi barb spigots are to be avoided and may as Roger suggests, cause damage to the inside of the hose.

As for clamps - all my fuel & oil hose clamps are multi use, smooth edged fuel injection style. My coolant hose clamps are the, now Rotax standard, spring clamps😈

If needed the 1" coolant hose can be purchased with a 90 degree bend. Some aircraft Mfg's put an aluminum tube in the hose at a bend or a spring. They all seem to work.