Recent problem since being the bike out over the winter. Bike sat with a full tank and fuel stabilizer in it. Starts great and haven’t had issues starting or at idle.

The problem occurs after riding for 10+ minutes. It’ll accelerate great once warmed up and within that 10 minutes. After that I start losing power with more throttle input and higher rpm. It gets progressively worse the longer I ride. At around 18/20 minutes of riding it gets so bad I can’t pull away from lights and have to shut the bike off. I wait 2-3 minutes. Starts right up and basically resets the entire process.

Wondering where to start. I know the fuel pumps might have issues, could be bad plugs but those were replaced 1 year ago and less than 1500 miles.

Any help appreciated

 

vent on tank isn't blocked by any chance? If you open the gas cap after 18mins, do you hear air rush in?

 

Does it vent through the gas cap right? I had replaced it in the fall with no problems after that.

 

Try riding with gas-cap open. See if it still dies after 10-minutes

 

So I didn’t ride with it open. But on my ride from work I started having the issue again, pulled over and opened the gas tank. Closed it and continued on after that (for like another mile till I got to my house) like it had reset itself.

When home I got the tank lifted up enough to see that on the right side was a nipple underneath that wasn’t attached to anything. There was a hose that also was attached to anything near to it. When blowing thru the hose it went around the front and out by the bottom left fairing. From my online searching this should be the breather/vent tube. So I had to pull a little more slack for the hose to reach the nipple and got the two put together.

Can’t test now as it’s late and my bike is pretty loud, but does this sound like it could be the problem??? And if this is the issue, why would it being disconnected make any difference if it’s still venting/overflowing etc etc ???

 

Vent hose connected or not won't change anything inside tank. Dripping petrol will just fall onto hot engine instead of going to ground.

 

So could the hose inside the tank be clogged. Or is it something else entirely?

 

That's just overflow drain from outside filler hole for water or when you over fill.

Actual vent to let air into tank when petrol leaves is in cap. If cap doesn't let air in fast enough, it causes vacuum in tank and prevents fuel from leaving. That's why you test by riding with cap open.

 

Not entirely sure that's correct - my CBR1000F uses that "overflow" tube for both - the gas-cap vents into the overflow space.

But in this case, with the overflow tube not connected, I do agree you are correct that it's the gas-cap not venting properly into the overflow space which is likely the problem.

 

So when test riding today I was having the cap open as much as i could. Roads are bumpy and with 3/4 a tank it was spilling out. I had to close it when doing anything other than cruising or sitting at lights. This should’ve been enough to never notice the issue if the tank was open for 75% of the ride today. Right?

It seemed to just delay the issue. I rode for around 30 minutes before starting to notice the problem come back. The only time I’m able to get it to work correctly it by shutting the bike off at stoplights and starting it again when it goes green. That seems to get rid of the issue like it did before.

I will note I have an aftermarket gas cap as well. I’ll attach a picture of the one I purchased.
A but I didn’t have issues with this in the fall. It was installed and rode for a good 2 months and 1000 miles with no problems