Throttle cuts out randomly at 4-5000rpm

[RickD.]

Hi all, I tried searching but didn't find anything on this topic, maybe I'm using the wrong search terms. Was out riding yesterday, and in 1st and 2nd gear under at least 50% throttle, the bike would cut out like it was starved for fuel. When I let off the throttle and gave it gas again it would act normally. It was fine in the morning, I made a stop for about an hour, and on the way home it was doing this. A friend said maybe there is a kink in a fuel line somewhere? About the bike:

2009 Gladius, 12,000km
Bought last year from a dealership, they performed a full service and the only fuel related things they did were to repair/replace the fuel gauge
Tank is about 1/2-1/3 full, low fuel light came on when I pulled into the garage.
Bike has been trouble free since I got it August 2024
This tank of gas has fuel stablizer in it, I haven't yet filled it with 'clean' gas.

I don't think this is a serious issue to remedy, but I'm not sure. Anyone have any thoughts? Thanks!

[Craig380]

Hi and welcome to the org.

Have you got an 'FI' warning in the dash? If so, you'll have a fault code / codes that could help diagnose the problem.

If you don't have an FI warning or check engine light, I would start by giving the bike a full check over. Check all 4 spark plugs are snug and not loose (new plugs can and do loosen themselves). Make sure all the spark plug caps are fitted correctly. Lift the fuel tank and check all the linkages for the main and secondary throttle valves, lubricate them with a teflon lube spray. Check for loose connectors, there are loads of them under the tank. Check the vacuum hoses around the throttle bodies for splits / holes. Use a torch to inspect the rubber vacuum caps on the throttle bodies. Are any split / dried out?

Any of the above could cause your symptoms, so take your time and look carefully. Good luck!

[admin]

Make sure your battery terminals are tight.

[Bibio]

Check your oil level. I hope your not doing wheelies as it kills the sv engines.

[Biker Biggles]

I'd look to putting fresh fuel in before getting too technical. You say there is fuel stabiliser in the tank so is the fuel old? Any chance there is water mixed in there? Used to be an issue with SV filler cap recess drains failing and letting rainwater into the tank.

[RickD.]

Originally Posted by Bibio

Check your oil level. I hope your not doing wheelies as it kills the sv engines.

Oil level is fine, no wheelies by me

[RickD.]

Originally Posted by Biker Biggles

I'd look to putting fresh fuel in before getting too technical. You say there is fuel stabiliser in the tank so is the fuel old? Any chance there is water mixed in there? Used to be an issue with SV filler cap recess drains failing and letting rainwater into the tank.

Fuel is maybe a few months old, no water in there as the bike is stored indoors and it's winter here in Berlin. I took it for its first long ride of the year this past weekend, and was able to replicate the problem when I leaned into a corner. This was before I filled the tank with fresh fuel, and since then I cannot replicate the problem so hopefully the problem is gone now.

I did also follow the above suggestions and made sure everything was tight, I could not find any obvious issues with vacuum lines, wires, etc. If the problem comes back I'll dig deeper into it, but hopefully it's gone. Thanks everyone for the help!

[garynortheast]

Great news! Let's hope the issue is permanently resolved then. Enjoy your riding.

[RickD.]

Originally Posted by Craig380

Hi and welcome to the org.

Have you got an 'FI' warning in the dash? If so, you'll have a fault code / codes that could help diagnose the problem.

If you don't have an FI warning or check engine light, I would start by giving the bike a full check over. Check all 4 spark plugs are snug and not loose (new plugs can and do loosen themselves). Make sure all the spark plug caps are fitted correctly. Lift the fuel tank and check all the linkages for the main and secondary throttle valves, lubricate them with a teflon lube spray. Check for loose connectors, there are loads of them under the tank. Check the vacuum hoses around the throttle bodies for splits / holes. Use a torch to inspect the rubber vacuum caps on the throttle bodies. Are any split / dried out?

Any of the above could cause your symptoms, so take your time and look carefully. Good luck!

No FI warning/check engine lights. I did give everything a quick look over and didn't see anything out of sorts. I filled the tank (about 2/3) with new fuel and am not able to replicate the problem right now, hopefully the issue was related to either quality/quantity of fuel, or when I checked it over I knocked something back where it needs to be. Hopefully this doesn't happen again, but if it does I'll take another closer look under the tank. Thanks for the help!

[Craig380]

Good stuff, hope it's sorted!