My motorcycle slowed down while I was giving it the throttle?

[Jack S]

I was on the highway going about 70, when I noticed that my bike started slowing down when I was still trying to increase the throttle. I thought I was running out of gas, so I changed the valve to reserve, which didn't help. I finally pulled off to the side of the road since i was going about 40 at that point.

The bike then also stopped running when I stopped.I checked my tank, and I still had gas. Then I couldn't start it back up again. I had to change the valve back to ON, and it started up after a few tries.

Anyone know whats wrong? I'm assuming its something with the fuel line, but Im inexperienced

[bikinkawboy]

So was the engine sputtering on all cylinders (assuming it's a multi cylinder engine) or did it seem to be missing on one or two cylinders? If the former, I'd be looking at fuel supply. As mentioned, it could be dirty filter, water in the fuel, clogged gas cap vent, old rubber hose getting hot and swelling shut, fuel pump going bad.

If the latter, I'd look at the magnetic pickup, the modern thing that replaced the old style points.

As far as taking a while to get going again, it could either have been fuel finally getting to the carbs or the pickup cooling off. Need more details as to brand, model, year, sounds it made or the way it acted, etc.

[Tibbsy!]

you might have blown your head gasket, i had a similar probelm with my bike as it lost power on full throttle and eventually cut out, after a few attempts it worked as normal but riding while this is blown can casue long term effects such as warped head and also lead to engine deteriation

[Bardic]

Could be dirt in the fuel. Could also be something as simple as dirt in the tank breather. Could also be that it was getting hot and tightening up, and when you'd stopped for a while it cooled down enough to slacken off. Did it turn over okay when you were trying to start it unsuccessfully? If so, it probably wasn't tightening up.

[750_Rider]

If it was a blown head gasket, you'd have milky oil in the bubble.
There should be a rubber tube from the tank to fuel cut off knob. Make sure it's not compromised and the clamps are good. There's another tube from the knob to the delivery. Inspect it as well. Make sure it's not burned or warped.
If your hoses are clean, I'd drain the gas, replace the fuel filter and fill it up with fresh 93 octane gas. (if it's 500cc or more)

A loose hand grip will allow the throttle to roll back during riding. Make sure the grip is holding.

Pay attention when draining the gas to see if there is any debris or rust in it. That would indicate the need to have your tank cleaned. I know of a guy who took his tank to a car wash and used the pressure hose to blow the gunk out.