GSXR750L fuel hose routing

[Crass]

I'm posting this up in case it helps others in future.  As most will know there isn't much room under the tank of oil cooled bikes leading to issues with trapped and kinked fuel hoses. This is made worse when things are not laid out as standard. I've found my bike to be a PITA as the fuel hoses were so short it was a real struggle getting them on and off the fuel tap with the tank not lifting enough to get in. As I was rebuilding the carbs and replacing the hard hoses here's what I've done.

First thing to note which is probably part of the problem is that routing on the L model is different and the change came with the RK model. Originally the hose feeding carbs 1 & 2 connected to the fuel tap outlet which points backwards and the hose feeding carbs 3 & 4 connected to the tap outlet which points across the engine. This was reversed with the RK and the hose from 1 & 2 now went straight forward to connect with the tap outlet pointing across the engine with the hose from 3 & 4 running parallel with the rear of the carbs before turning 90 degrees to connect with the tap outlet pointing backwards. Owing to the extra plumbing under the tank if the hoses are not routed correctly you stand the risk of them becoming trapped. 

On my bike as it came to me the hoses were routed wrongly as per earlier models and were too short to be routed as per the service manual routing diagram. The associated anti-kink protection springs were also only long enough for these truncated hoses. Did it come like this from the factory, who knows?

So, the picture below should be self explanatory and show the correct revised arrangements which I have installed. For reference I have used 11mm OD hose and the one connecting carbs 1 & 2 is 38cm long, the one to carbs 3 & 4 is 35cm long. I bought another length of OEM anti-kink spring (still available) and snipped it into two 12 & 15cm lengths and added it to the extended hoses with the original springs. It fits just right to 11mm hose providing support against kinking and the combined lengths compress the springs slightly adding protection. Be aware that you will probably get a sharp burr when you snip the spring so smooth that off and to be extra safe position the cut spring so the snipped end is at the fuel tap end, so the smoothest as-supplied end is in the middle of the hose. Spring clips for 11mm OD hose will fit over the hose at the fuel tap outlets ok (not the case if you use bigger OD hose as there is limited clearance for a clip to slip on).

I find that with this arrangement the tank can be tilted plenty far enough up for easy access to the hoses, they fit in the space available without being trapped and they curve without kinking. The springs also provide protection against contact with hot surfaces, although as set out above they do not contact the engine (although it will still be a bit toasty under there).

 

 

Edited December 4, 2024 by Crass
Better photo